Wednesday, December 30, 2009

Angora and a Little Rascal

With the flowering of each new cross, I get more and more excited about the potential for hybridizing within the genus Petrocosmea! I often think back to what it must have felt like for those very first hybridizers of African violets and then reflect upon the myriad of flower and foliage variations available today within that genus. Looking at a collection of species Saintpaulia, one might never imagine the variety that would have evolved from those charming, but fairly simple and uniform flowers and foliage types among the species in that genus. Oh, the things that are yet to be within the world of Petrocosmea!!!!! ( I can dream, can't I???)

The subject of my current adoration is the offspring from a cross between P. forrestii (as the seed parent) and the magnificent, and quite unique P. duclouxii. Both very different from each other in a number of ways. I was on Cloud Nine when I saw those seedpods developing! Now, ten months later, the babies have grown up and are showing first flowers. I've selected two from among the twenty that I flowered to name,and one other one which is remaining unnamed for the moment. P. duclouxii was clearly dominant form flower type in every seedling. P. forrestii was dominant for foliage type among all but one of the seedlings. Flower size was a mixed bag, with about nine having smaller flowers like forrestii and 11 having larger flowers like duclouxii. Peduncle length was clearly influenced more by forrestii...which I was not so happy about. Now, here are the "kids"........

Petrocosmea 'Keystone's Angora' was the first selected and named. It was chosen for it's magnificent foliage, which appears as a large P. forrestii, but the leaf texture is outstanding. I wish you could touch the screen and feel these leaves! They are literally as soft as angora! I HAVE to pet them everytime I see this plant. Hence, the name! The plant is showing more buds to come. I'm hoping for a bit more bloom with maturity, since both parents are quite floriferous.

The flower of P. 'Keystone's Angora' ...a smaller version of it's P. duclouxii parent, but a bit pinker, due to the influence of forrestii. Petals are rounder and more obtuse on the tip, making the flower less "starry" than those of P. duclouxii. Anthers are deformed, producing no pollen, but the pistil appears normal. I'm hoping it will be seed-fertile.

The second seedling names is P. 'Keystone's Little Rascal'. Leaves are more like duclouxii in shape and texture, with some veining, but size of the foliage is more like forrestii. It was chosen for it's heavy flower count and small size. It was the only seedling to inherit the shorter, sturdier peduncles of P. duclouxii. All other seedlings have the long, unruly peduncles of P. forrestii...and undesirable trait in my opinion. This plant did form two offsets, which I was not happy about, however, it's positive qualities of heavy bloom count, peloric flowers, most with extra petals, and the sturdier peduncles won out. The flowers on this plant are quite small, among the smallest of all it's siblings. I'm happy with it's reduced size and compact habit.

Most of the flowers (92% of them) were near-peloric and had extra petals. Again, as with all of the flowers in this cross, the anthers are deformed and produced no pollen. Pistils appear normal.

One other trait from this cross which I was very happy about, was that it produced three very small, almost "miniature" seedlings. This is the third Petrocosmea cross, involving larger parents that has show a tendency to produce a few "miniatures". My first cross, P. rosettifolia #3 x sericea produced one miniature plant, which pure white flowers (P. 'Keystone's Bantam'). By using P. 'Kesytone's Bantam' in a cross with P. forrestii (the most compact of the species), I got 100 miniature seedlings...all MUCH smaller then 'Keystone's Bantam'. None of these have flowered yet, after 11 months, and most all are producing HEAVY offsets, a trait which I am attempting to select out of the hybrids that I release, so I am not sure that I will ever release any of these. These miniatures do, however, give great hope to me that miniature Petrocosmeas are a real possibility and likely not too far in the future. Just one more exciting and mysterious trait tucked away within the genetics of this genus.

A photo showing the difference in the size of the flowers of P. 'Keystone's Little Rascal' (on the right) and one of it's siblings....(which I have not named so far). Both of these are smaller than the parent P. duclouxii. Petal shape, petal width and length all were quite variable, as can also be seen in the photo The petals of the larger flower on the left are more oblong and narrow, giving the flower a more "star-like" appearance. The petals on 'KLR' on the right are shorter and more ovoid in shape, making the flower appear rounder and fuller.
And, as must be done, the remaining 17 seedlings all went into the trash bin...... Rest In Peace!

Monday, December 28, 2009

A "Child" Grows Up... Petrocosmea 'Rosemary Platz'

In a recent post, I promised that I would post a photo of my first named hybrid P. 'Rosemary Platz' as it came into full bloom this season. This was the hybrid that heralded the beginning of what has been an incredibly rewarding, enjoyable, and educational experience for me. It happened by accident, really.

A couple of years ago, after having tried for nearly ten years to get Petrocosmeas to set seed, I made yet another attempt. Due to impending long days and heavy weeks ahead with my shifts at work, I had placed several of my Petrocosmeas that were showing buds underneath a humidity dome in my basement light stands. In early October, two species were sitting side by side underneath one of those domes, and both were in flower. P. rosettifolia #3 and P. sericea. So, on a whim, I took the pollen from both flowers and made reciprocal crosses between the two species. I then put it out of my mind, assuming, as had always been the case, that both would fail. A month or so later, when I had a chance to check on my plants in between shifts, I noticed seedpods forming on both species!!! WHAT?!! It couldn't be! But, yes, there they were...five seedpods... three on the rosettifolia and two on the sericea! I don't recall how many flowers on each species I had pollinated, but some had indeed worked. Sixty-seven days later, I harvested the seedpods from P. rosettifolia, and then about two weeks after that, the seedpods on P. sericea were harvested. There were seeds inside of all of them.

Eight months after sowing the seeds, the first seedling from the rosettifolia x sericea cross was on what had been the most vigourous seedling all along....that plant later was named P. 'Rosemary Platz' after a dear friend. That first year, the plant had five flowers, but the foliage was really nice, and it shaped up very nicely.

Petrocosmea 'Rosemary Platz' in it's third season of a mature plant. It has exceeded my hopes and represents three qualities that have now become standards that I select for in all of my Petrocosmea hybrids.....floriferousness, reluctance to form offsets, and attractive, ornamental foliage.

A mature plant of P. 'Rosemary Platz' just coming into flower. This hybrid has attractive foliage, showing the glossiness and lighter yellow veining of it's P. rosettifolia #3 parent. It gets it's leaf shape and size from it's P. sericea parent. An additional plus is that after three seasons of bloom, the original plant has never yet formed a single offset...a trait that I select for in my hybrids. The tendency to offset at flowering ruins many showplants...and is a nasty trait of the P. rosettifolia species used as a parent. P. rosettifolia #3 is the form with yellow veining that is least likely to offset. Form #4 offsets very heavily and is the form of this species that, for me, is the most reluctant to flower. By chance, I used form #3 in this cross.....that was purely an "accident"...but was a happy "accident".

My friend and hybridizing mentor, Dale Martens, took this photograph of a dissected flower of P. 'Rosemary Platz'. This photo shows the attractive purple stigma at the tip of the pistil, and the feathery white furriness of the filaments supporting the anthers.... both traits that neither of this hybrid's parents have. SO where did these traits come from???? ("Thank you" Dale, for allowing me to use your photograph!)
As my third year of Petrocosmea hybridizing comes to a close, I've been very happy with my first hybrid. I've been delighted at the response I've gotten from Petrocosmea growers and gesneriad enthusiasts in general about this hybrid and I hope that it will become a welcomed addition to the world of gesneriad hybrids. This year, I've attempted to take things to the next generation, as I've begun using P. 'Rosemary Platz' and it's siblings, as parents in new crosses. They are now forming seedpods....indications that they may be both pollen and seedpod fertile. I'm excitedly looking forward to the future to see how my "child" behaves as a "parent".

Monday, December 21, 2009

The Winter Solstice

Today marks the Winter Solstice in the Northern Hemisphere. That means that beginning tomorrow, the days will grow longer. Even though I grow my Petrocosmeas primarily in a basement room with no windows, and the lights are timed the same year round, the plants always have a way of sensing this natural cycle. It always amazes me that they know, but somehow they do.

Some species of Petrocosmea have an annual growth cycle that involves what I have come to term a "semi-dormancy". Right after the autumn and winter flowering period, the plants begin to decline. The outer leaves begin to yellow and will eventually wither. In the center of the plant, the crown of new leaves become thickened and tight...almost as if the plants have an infestation of cyclamen mites. They don't. This cycle repeats every year for some species, and they always burst into rapid, lush growth each spring. The species that exhibit this pattern of growth, for me, are: P. nervosa, P. sp. 'vittatae', P. barbata, P. formosa, P. flaccida, and P. rosettifolia forms #1 and #2. Some hybrids involving these species in their parentage will also show a modified "semi-dormancy". The hybrids exhibiting this modified semi-dormancy are: P. 'Momo', P. 'Asa Blue', P. 'Imperial Butterflies', P. 'Short'nin' Bread', and P. 'Fluffer Nutter'.

One of my two mature plants of P. sp. 'vittatae' after a heavy flowering period. I allow the plant to dry out more between waterings and keep the plant cool. I will groom the dead leaves and flower peduncles off the plant, and will not fertilize it again until I begin to see new growth from the tight silvery center crown of the plant next spring.

The tight, silvery crown of P. sp. 'vittatae' as it retreats into it's annual semi-dormancy. I allow the plant to 'rest' until this center crown begins to expand with lush new growth next spring.

A mature plant of P. barbata 'Keystone'. This plant has been a workhorse of bloom all summer and was the parent of two hybrid crosses when it produced seven full seedpods. It's is deserving of a winter rest. Note how the outer leaves are beginning to yellow. The center crown is taking on the tight, gnarled appearance of it's semi-dormancy. This plant is NOT dying, but resting. Allow it to stay cool, drier, and give it no fertilizer over it's rest. When the new growth begins to emerge next spring, it will make rapid, lush growth. By keeping the roots drier, you avoid rot and root loss. This preserves that large, mature root system, which will support a large, full head of leaves next season. This large rosette of leaves, will nourish a heavy bud and bloom set next season.

The tight, silvery center crown of a P. barbata that is entering it's annual semi-dormancy. The plant is not dying, merely resting.
As the Petrocosmeas wind down from a heavy season of bloom and enter this annual semi-dormancy, it is important to realize that they are not dying. This is a nature response to the changing seasons, shorter days and cooler temperatures of winter. The key to saving these plants is to recognize what is happening and to provide the proper care when this occurs. It is easy to rot the root system if watering is not adjusted. As the plant drops it's leaves, it requires much less water and nutrients to support life. Watering schedules should be adjusted to allow the plants to remain drier, with only enough water to support the very tiny center crown which remains. If done correctly, the mature rootmass will be preserved. This larger mass of roots, next spring, will support a much more lush, and rapid return to full growth. The rosette will be renewed in a shockingly rapid growth spurt. Once growth resumes, I remove any additional offsets or crowns and repot if needed. I DO NOT repot all plants. If a single crown remains and the plant is otherwise happy, I will simply remove the top quarter inch or so of soil and replenish it, add systemic pesticide granules and give the plant a weak fertilizer until new growth is well advanced. Then, I resume my normal care patterns.
Lastly, I will mention that plants grown on reserviors of fertilizer water using the wick watering method, and plants that are kept in a constantly warm environment may not experience this semi-dormancy as markedly as my plants. I attempt to grow my plants as close to what I think their natural habitat provides as possible, so I allow my plants to get quite cool, even cold by some people's standards. I also allow plants to dry out between watering and reduce fertilizers to the point that I am using only plain water for non-blooming plants at this time of year. This is why, I feel, my plants exhibit this pattern.

The Rosettifolia group - Part IV - Still One More!

In this post of the series on The P. rosettifolia Group from my collection, I will discuss the most reluctant to bloom of the four forms I grow. This form of P. rosettifolia is the one that I label #4 in my collection. It is most similar to form #3 in several ways, but is easily distinguished from form #3 when the two are compared side by side. This form has a tendency to form offsets more than any other form of the species. It's foliage can be the most ornamental, however it's reluctance to bloom and it's tendency to form offsets can make it a challenge to produce a beautiful, blooming plant of this form. In fact, this form never flowered at all for me last year. I had three mature, large plants in my collection and not one flower. They were all grown on the same shelf as the other three forms, all of which flowered heavily. This makes it unlikely that I will use it much in hybridizing. I maintain it in the collection for it's genetic diversity and scientific value.

The flowers of this form of P. rosettifolia have curled petals, deep green "hoods" formed by the upper lip of the corolla and a slight purplish blush to the lower petals.
The flowers of P. rosettifolia #4 have pistils that point upward, due to a curve at the midpoint of the pistil. All other forms of P. rosettifolia present the pistils horizontally and straight.

While the ligthing in this photo is too bright, one can still see the shape of the leaves of P. rosettifolia #4. In this form, the leaves have the attractive yellow central and lateral veining, however, the green is deeper, almost black with good lighting. Leaves are more narrow and the teeth along the margins are present only along the distal half of the leaf. The lower portion of the leaf at the base has smooth margins, without the teeth.

The pistil of the flowers of P. rosettifolia #4 has a curve at the midpoint. This causes the tip of the pistil to be pointed upright, looking almost like the horn of a unicorn emerging from the flowers. The pistil on the other three forms of P. rosettifolia in my collection have straight pistils, which present horizontally from the base of the flower.
The cymes of P. rosettifolia #4 have three bracts, as does form #3. Forms #1 and #2 have only two bracts. The bracts on form #4 are longer and more linear than those of the other three forms.

So there are at least four distinct forms of the species labeled P. rosettifolia in cultivation. I have also seen photos that may indicate there are still other forms of this species out there also. Each species has distinct morphological differences, and DNA testing done on the four forms in my collection does confirm that they are unique individuals within the same species. Judges should keep this in mind when judging this species, as the size and ornamental value of each form can be quite different, as can the propensity towards forming offsets. The amount of bloom for each form can also vary quite a bit.

I will likely be making a couple more posts in this series in the near future. As additional plants that I lump into this group come into flower, I'll review them. The "P. rosettifolia Group", so far, promises to be the largest grouping of individual clones of species and close relatives, that my, with time, be shown to be additional forms or varieties of this species. I place them all within this "group" due to morphological and DNA data. Admittedly, this is a group the I alone, have created, and more learned minds than mine may have different opinions on the subject. Still, other species being grown currently under other names, such as P. sp. 'Chinese #2' , sp. 'China 2005', and the species 'Yumebutai' are the current focus of some study in an attempt to identify proper placement of these individuals within the genus.

Wednesday, December 9, 2009

Looking Back and Looking Ahead... Hybridizing Petrocosmea

If you will allow me to deviate from the thread on P. rosettifolia and it's variations, I had to take a few minutes to update you on the seedlings that are flowering now from last year's crosses and the seedpods that are forming on this years new crosses.

With the year 2009 quickly winding down to it's end, I had to take time today to go back and take another long, careful look at the batches of seedlings that are still flowering in the basement plant room. I've spent the entire year nurturing these precious little plants as they went from seedpod to flowering plants. What great fun this journey has been. I've been priveleged to see some seedlings that no one else has seen and evaluated. That's one of the exciting things about hybridizing in general and hybridizing a largely unexplored genus such as Petrocosmea in particular. I've filled my lightstands, my notebooks, my computer (with notes and photographs) and my trashcan as these seedlings matured, some to reveal "keepers" and some to reveal plants that lacked anything new, attractive, novel, or better than the parents. It is a heartbreaking task, to destroy a seedling that is the result of one's own efforts, but it must be done, and I'm proud to say, I've done it. In the end, I've selected some exciting and promising new hybrids for further evaluation.

I'm enjoying the results of two crosses that are now reaching the peak of bloom. The seedlings are the results of crosses between P. sericea x P. minor veined leaf form, and P. forrestii x duclouxii. Both of these crosses have produced variation in both foliage and flowers.

I've snapped some photos this evening of three of the most desireable from the P. sericea x minor seedlings. Foliage on these three is pretty much intermediate between both parents, but the flowers are showing some nice variation in size and coloration.

Three seedlings I'm keeping for further evaluation from a cross between P. sericea x minor veined leaf form. Note in the photo the variations in color of the petals, and the markings in the throat. The seedling in the middle has a clear demarcation between the clear white throat and the medium purple petals. All three flowers have a deep blackish purple dot in the base of the throat. The one on the right is a dark bluish purple, which the camera did not capture accurately. It is darker and more blue than the photo shows. Also note the large leafy bracts on the flower on the right, compared to the tiny bracts on the other two...this is consistent on all peduncles on this seedlings.

This seedling, the one on the right in the first photo, was the only seedling out of twenty to develop large leafy bracts on the peduncle. The hairs on the calyx lobes are also denser and longer than on other seedlings. It's color is the darkest of all of the seedlings in the batch although this photo makes the flower look much lighter in color than it really is.

This seedling has flowers with a clear, clean white throat that is nicely demarcated from the purple in the petals.

The flower on this seedlings is the largest of the batch of seedlings, and consistently has six petals while most of the other seedlings have five. Peduncles are nice and dark in color and are strong enough to support the large flowers. Bud and bloom count was also high for the parentage of the cross. Both parents are not usually heavy bloomers.

The second cross in flower now is P. forrestii x duclouxii. I have selected two seedlings so far, one of which I have named P. 'Keystone's Angora' due to it's soft, silvery furry leaves...the softest of any Petrocosmea that I have in my collection! Of the three seedlings selected, two have been in flower for a couple of months now and are continuing to produce buds...which bodes well for the flower count. The flowers of these two are quite different in size and show a variation in flower shape each taking after a different parent. See the photo below....
Flowers from two selected seedlings from a cross between P. forrestii and P. duclouxii. The flowers are quite different from each other in size. The flower on the left is from an as yet unnamed seedling that is taking it's plant/leaf size and flower shape and size from the P. duclouxii parent. The flower on the right is from a seedling named P. 'Keystone's Angora'. It's flower size and shape is more like it's P. forrestii parent, although both flower size and plant size is larger than P. forrestii. I attempted to pollinate the flower of P. 'Keystone's Angora' with pollen from P. begoniifolia and have several seedpods. You can see inside the throat of the flower in this photo that a small green seedpod is beginning to enlarge....indicating that it may indeed be fertile as a seed parent. Neither flower produces pollen so cannot be used for further breeding as a pollen parent.
While looking back at the past year's successes and failures is fun, rewarding and educational, I am also quite excited to see many seedpods forming on crosses I've made this flowering season. I noted seedpods forming this evening on the following crosses:
P. forrestii x formosa
P. rosettifolia #3 x minor veined leaf form
P. menglianensis x begoniifolia
P. 'Keystone's Angora' x begoniifolia and
P. 'Rosemary Platz' x (Asa Blue x begoniifolia)
I am transplanting small seedlings from crosses of P. forrestii x minor smooth leaf form and P. forrestii x sericea.
With all of these new crosses forming seedpods, and more plants still to bloom, there are still many exciting possibilities still ahead for the year to come. Wish me luck!

The Rosettifolia group - Part III - Yet Another One!

Certainly my favorite in the "Rosettifolia Group" is this species, P. sp. 'China 2005' The flowers are a lovely purple and the plant is literally loaded with buds and flowers. Easily the most floriferous species of the grouping.

A photo of one of my three plants of P. sp. 'China 2005' just coming into flower this week. This plant is three years old. Maturity of at least three years on Petrocosmea plants is proving to be a factor in heavy bloomset. Most Petrocosmea seen in shows, I suspect, are less mature at one to two years, and therefore often don't show a heavy display of bloom.
Here is yet another plant which I feel based on both morphology and DNA studies,belongs in the the "Rosettifolia Group". It is either another clone of the plants currently labeled P. rosettifolia in the USA, or at the very least, is a close relative or variety of that species. This plant was imported, by myself, as a wild collected plant in the year 2005. In the catalog from which it was purchased, it was labeled P. forrestii... it clearly is not. It shows no similarities with that species. In morphology, it is most similar to the P. rosettifolias, however neither it, nor any of the other plants currently labeled P. rosettifolia match the published description of P. rosettifolia in the Flora of China. AAahh, yes, yet another identification issue with our beloved genus Petrocosmea!
Recent DNA work is showing that P. sp. 'China 2005' is very closely related to the Rosettifolia grouping of species. It may turn out to be another clone of that species, (whatever it is) or at least a variety of that species. The only morphological difference that I can see is that the corolla color is deep purple, whereas the corollas on the other individuals in this grouping are white to very pale lavendar at best. The flower structure and plant structure and habit all match, however. This bloom cycle, I hope to try crossing it with my P. rosettifolias to see if they cross with each other.

The leaves of this species are plain, deep green and have a rough texture due to the short hairs. Leaf size, shape and plant size and habit all very closely resemble P. rosettifolia #1 and #2. This form is a very heavy bloomer...producing waves of buds over a period of four to five months in my conditions. Flowers are a lovely deep purple with a striking, purest white throat, which is slightly green at the very base of the tube. Petals most always number five...two up and three down, with the upper petals fused and bending forward to form a green "hood" as all of the other P. rosettifolias do. The flower morphology places the plant in Section - Anisochilus of the genus.

I have distributed leaves to a number of Petrocosmea growers over the past four years, and hope that this species will get into wider cultivation. It is a lovely plant in flower, and deserves a safe place in cultivation. Since it's place of collection is not known, and with the rate of destruction of habitat in China, it is a constant fear that this species and other plant species will be or may already be lost to nature forever. Keeping them alive in our collections and our hearts and hands is one way to ensure that they continue to amaze and delight us and future generations for years to come.

In bloom, this is one of my most favorite of all Petrocosmeas! Really! The masses of violet purple flowers on wiry peduncles are a lovely, charming gift each December, and they often last four or five months in my basement growing area. No other species has flowers this small and of this shape and color. Most others with this size and shape of flower have pale lavendar or white flowers, so this species is unique in that regard. Out of flower, however, this species is admittedly a bit lackluster in appearance.

Compare the form of this species with that of P. rosettifolia #1 and #2, and perhaps even P. menglianensis in my previous posts. It is hard to tell them apart. The key difference, for me, is that the leaves of this species feel "rough" when compared to those of the other species. Very "sandpaper-like" in texture.

One of the features of this species, which in my opinion detracts, is it's pesky tendency to form offsets when mature. Maturity brings a very heavy budset and flower count, but with the nuisance of offsets which spoil the flat, symmetrical shape of the plant's rosette, which it has to perfection as a younger plant. As can be seen here, even the offset if putting up a few buds.... This little species just loves to bloom!

So, to recap this thread of posts, so far, we have P. menglianensis, P. rosettifolia #1, P. rosettifolia #2, P. rosettifolia #3, and now P. sp. 'China 2005'. There are still others to come! While these plants as labeled, are called by various names at present, they may all turn out to be mislabeled. That is why I refrained from applying a species name to the species covered in today's post, and chose instead to just call it P. sp. 'China 2005'. Such labeling will indicate it's genus, place of origin and the year it was collected.

Saturday, November 28, 2009

The Rosettifolia group - Part II

The next form of "the Rosettifolias" is perhaps the most ornate of them all. The foliage on P. rosettifolia #3 is very showy indeed. It is often a winner at shows when out of bloom due to the light yellow veination along the central and lateral veins of the deep almost black-green leaves.

Petrocosmea rosettifolia #3 is also sometimes labeled P. sp. 'G25KC00'. It was brought into cultivation around the year 2000, after being imported from Chen Yi Nursery (or Kaichen Nursery) in China as a wild collected plant. This form produces the largest rosette of any of the forms. Leaves are more elliptical in shape, forming a sharp point, with teethed or serrate margins. The leaf is very deep glossy green, almost black in the right light. The centers show a bright yellow veination along the central and lateral veins. Leaves are covered in a course hair and have a rough texture. The rosette tends to be very symmetrical naturally. This form does produce offsets quite readily as it approaches flowering, which unfortunately, often ruins the flat rosette. Flowers are produce singly, on stout light green peduncles, with three bracts. Flowers on this form are clear, bright white, with a yellow throat, and often have four or five lower petals.

A flowering plant of P. rosettifolia #3 showing it's white flowers over the striking dark foliage.

The clear white flowers of P. rosettifolia #3 have a lemon yellow center and usually extra petals. Note how the two upper petals are fused into a green hood on the top of the flower. These petals, if measured from base to tip are about one half the length of the lower petals...a characteristic which places this species within Section Anisochilus of the genus Petrocosmea.

My show plant of P. rosettifolia #3 entered in the July 2009 annual convention show of the Gesneriad Society in Silver Spring, MD. The plant won both a first place in it's class and Best Petrocosmea in the show....likely due to the extra ornamental value added by the yellow center veining of the glossy leaves. The contrast is quite showy. The plant was seven inches in diameter.

This photo shows the peduncles on P. rosettifolia #3 which have three bracts, instead of the two bracts found on forms #1 and #2. This form's flowers also have extra lower petals. This photo also shows the rough texture to the glossy leaves and the teeth along the leaf's margins. (The white tag is marking the parentage of a seedpod on the peduncle on the left.) The more compact rosette of P. rosettifolia #2 is in the background. Note that it does not reach the margins of the 5" pot, while the leaves on the larger rosette of #3 are extending over the pot's edge.

A favorite shot of the center of the rosette of P. rosettifolia #3, shows the nice yellow veination forming a yellow feather pattern in the center of the leaves. Even without flowers, this form is a showy plant.

The Rosettifolia group - Part I

When I first began to assemble a collection of every known Petrocosmea species in cultivation, about five years ago, I noticed that I had two different plant labeled as Petrocosmea rosettifolia. They looked different in several ways. Then as time went on, I began to notice that some of the P. rosettifolias entered in shows were different from the two plants I had. I decided to get leaves of all the various forms I could find and conduct an experiment. I put leaves of all four forms that I had collected down to root on the same day. I treated them identically in every way. When they had formed plantlets, I divided and potted up the plantlets on the same day, using the same soil, pots, fertilizer, etc. I grew them on the same shelf of my lightstand. The culture was identical in every way, at least as much as I could make it so.

As these four individuals matured, I could easily see the differences. I decided to label them P. rosettifolia #1, #2, #3, and #4 so that I could keep them seperately identified and kept records of each form.

Were they different species, or just different clones of the same species, perhaps from different collections or populations in nature? Those questions are still being answered, but with time, based on morphology and now some new DNA analysis, I am convinced that they are indeed four unique individuals within the same species. I do, however, have real doubts that they are indeed the true P. rosettifolia, but I am leaving them labeled as such for the timebeing.

I feel that it is important to both Petrocosmea admirers as well as AV and gesneriad judges and exhibitors to know that there are four different clones of this species in cultivation and they grow and perform differently. Furthermore, I believe that the plants now being grown as P. menglianensis and P. sp. 'China 2005' may also be two additional clones of this same species, based on the DNA analysis which is being done as well as morphological characteristics of these plants. Two others, P. sp. 'Chinese #2' and P. sp. 'Yumebutai' is also very closely related to this group and may be two additional forms of the same species. I refer to all of these collectively as the "Rosettifolia group".

I decided to review the four forms that I have identified here.

The first is of course, P. rosettifolia #1. My plant was labeled as coming from the collection of the late Maryjane Evans, and it is believed to have been a plant collected in China around 1998-2000. This form is the smallest of the four clones in plant size. It has never reached the edges of the 5 inch pan pot in which I have grown it for the past three years. It's rosette is rather tight, and leaves are the smallest of the four clones, and are nearly plain dark green, with only a slight gloss to them. The yellow center vein coloration so prominent in the leaves of some other forms of this species, is very faint in the leaves of this form. Leaf margins are entire, or smooth, showing no teeth as some forms do. The flowers of this form are produced on single-flowered peduncles, with two bracts, which tend to be the shortest peduncles of the four forms and the most often curve gracefully at the tip, causing the open flowers to "nod" downward slightly. The flower form shows two fused upper petals forming an hooded lip, which is green in color and only half the length of the lower three petals, which are a pinkish lavender in color. It forms a rather charming little rosette when in flower. It is a favorite of mine for it's simple charm.

A blooming P. rosettifolia #1, showing it's charming simplistic habit.

The flowers of P. rosettifolia #1 are the closest to pink of any Petrocosmea species in my collection. The subtle coloration of pink, lavender, white, creamy yellow and green is lovely.
The next is P. rosettifolia #2. The origin of this plant is unclear, but it was believed to have been brought into cultivation via a purchase from Chen Yi Nursery, in China. My plant was purchased from a commercial vendor here in the USA four years ago. This plant is very similar to #1, but grows a bit larger in all it's parts. Leaves are larger and the rosette just reaches 5 inches in diameter. Leaves are a bit glossier than #1, and the rosette is slightly more open in form. Flowers are nearly twice the size of the flowers on P. rosettifolia #1. The peduncles are single flowered, with two bracts and are very straight, with little or no curvature at the apex once the flower buds open. Flowers are presented facing outward and upward. Coloration on these is more lavendar, with little to no pink coloration. Flower form is identical to form #1 and very similar to P. menglianensis. This form appears identical in all respects to the plants now being grown here in the USA as P. sp. 'Chinese #2'.

A blooming plant of P. rosettifolia #2. A bit larger than form #1, again without the yellow central veining that some forms show. Leaf margins are entire, showing no teeth. This form bear two bracts on each peduncle.

The flowers of P. rosettifolia #2 are twice the size of those on P. rosettifolia #1.

This photo shows P. rosettifolia #1 on the lower left, with P. rosettifolia #3 above. You can just see the leaves of P. menglianensis to the right of P. rosettifolia #1.. Note the difference in the rosettes of each species, along wit the leaf margins and the yellow veination of the leaves on #3. I believe P. menglianensis to be the same species as the rosettifolias. It's leaves are quite large, and show the yellow veination that form #3 does, but have a smooth or entire margin, whereas form #3 had a serrate leaf margin and a narrower, more pointed leaf shape.

By growing the various forms side by side, it becomes easy to note the similarities and differences in the plants. The photo above shows how they were grown on the lightstand. Note the white acrylic blanket matting in the bottom of the nursery tray, which is used to maintain higher humidity around the plants.

A couple of additional points I'd like to make about the various forms of P. rosettifolia. Forms #1 and #2 have smaller habits, which judges should take into account when judging these species. The leaves are less ornate, having plain green coloration. The leaf margins are smooth, or entire on the forms #1 and #2 and are serrated, with teeth on forms #3 and #4 which will be discussed in the next post. The peduncles of forms #1 and #2 consistently have two bracts, while those of forms #3 and #4 consistently have three bracts per peduncle. Last, I would like to state again, that these plants are labeled P. rosettifolia, but I believe they are NOT the true P. rosettifolia as described in the Flora of China. I believe they may indeed be an undescribed species. DNA evidence being finalized now, shows that the four forms of P. rosettifolia that I am describing here are very closely related, so closely that they are likely all the same species.

Thursday, November 12, 2009

Petrocosmea menglianensis - Or NOT?

I've posted previously about the maddening problem with Petrocosmea species having been introduced under erroneous names. This misidentification or mislabeling, or whatever we choose to call it is a mess now to sort out. I'm excited that there may be some hope towards correcting at least some of the names in the near future.

I've written and spoken for some time now about the particular problem with those plants currently labeled as P. "rosettifolia" and/or P. sp. 'G25KC00'. (Honestly, in my opinion, the label 'G25KC00' is probably the most responsible labeling we could apply to this group of plants right now.) Over time, I have collected at least four different individuals (clones) with these labels. These plants all show similar, but individual characteristics. In my opinion, after growing them all side by side, and conducting a little research of my own, I feel they are all seperate individuals of the same species. Now, I have yet another plant that I would like to add to this grouping - Petrocosmea "menglianensis".

A young, flowering plant that I acquired as P. "menglingensis" (there is no such species with that spelling, I feel it was supposed to have been labeled P. menglianensis (the published spelling of a species). I now feel this plant is NOT P. menglianensis either, but another clone of the grouping currently knows as P. "rosettifolia".

The flower of P. "menglianensis" is almost identical to the flowers of the four individuals that I have acquired as P. "rosettifolia". The flower on this plant is a bit more lavender in color, but morphologically is identical to P. "rosettifolia" flowers.

A side view of a flower of P. menglianensis shows the upper lip, which is the fused upper two petals. The upper lip of the flower is roughly one-half the length of the lower petals, a trait that likely puts this species in Section - Anisochilus of the genus Petrocosmea.

A flowering plant of P. "rosettifolia" #2, the plant is almost identical to the plant labeled P. "menglingensis" when I acquired the former. The plants have near identical flowers and the leaves are identical except that the leaves of the plant labeled P. "menglingensis" are nearly twice the size of the leaves of P. "rosettifolia" #2. I feel they are two seperate clones of the same species.

A flower of P. "rosettifolia" #1, again, nearly identical to the flowers of P. "menglianensis". This form of "rosettifolia" is the smallest of the now five forms of the species that I have. The cymes on this form are darker purple in color, shorter, and tend to curve, causing the flowers to "nod".

I realize this is all very confusing. Here's the breakdown of what I am attempting to say here:
#1 There are at least four different individuals of the same species all labeled as P. "rosettifolia". I feel that this new plant, which I acquired as P. "menglingensis" is yet another form of the same species.
#2 All four (now five) plants in this grouping all likely NOT the true P. rosettifolia. None of them match the published description of that species in the Flora of China.
#3 The plant which is the subject of this post originally came to me, and is still being sold and distributed as P. "menglingensis"...which is an erroneous spelling of P. menglianensis (the published species name). I feel that this plant is NOT P. menglianensis, and is yet another different clone of the plants all now being grown as P. rosettifolia. It is NOT P. rosettifolia either, but is almost identical to all of the other plants being grown under the erroneous labeling of P. rosettifolia.
#4 If my hunch is true, there are now at least five different individual clones of this same species, which is not yet properly identified.
#5 If you have this plant, I would recommend continuing to keep it labeled as it is, in order to identify it seperately from the other "P. rosettifolia" clones....BUT with the knowledge that it is likely not either P. menglianensis OR P. rosettifolia....we simply don't have a proper identification on any of these plants at present.
WHEW!!! I hope this is all as clear as mud, at least. Either way, the plant is still lovely, and a welcome addition to the genus in my plantroom. It does grow much larger than any of the other forms of the species (whatever species that is?) and should be grown in for no other reason than to preserve it's genetics. The leaves on this form get quite large on a mature plant and with maturity, in it's third of fourth year, it can bloom quite heavily.

Wednesday, November 11, 2009

Petrocosmea 'Keystone's Harvest Moon' - A Petrocosmea For Autumn

Sometimes, one of the toughest things about hybridizing gesneriads is selecting a name for the hybrids. (the second toughest thing is the selection process where most of the seedlings to flower must be thrown into the garbage bin!) I was surprised a couple of years ago, while looking at a batch of hybrid Petrocosmea seedlings to note that one of them had leaves that were yellow...definately more yellow or golden than all of it's siblings. My first thought was that the plant was just chlorotic, so I repotted it and gave it a heatlthy dose of fertilizer. It only became more yellow! As the plant matured, I had removed some of the leaves to test whether the propagations from the leaf cutting would show the same trait. They do!

This seedling was eventually selected due to the unique trait of the golden yellow overlay of color on the leaves. I noted that various exposures to light produced slightly different degrees of intensity in the yellow coloration, but this plant always remained more yellow than all the other Pets. I suspect that it's parent, P. rosettifolia #3 which was used due to it's deep yellow veining in the leaves is the contributor to this trait. The flowers, being light lavendar, make a lovely color contrast to the yellow foliage.

So, what to name it? The yellow color appears to be overlaid upon the green leaves underneath, like the glow of a full moon upon an object, so I was inspired to name the plant 'Keystone's Harvest Moon'. The cross is P. rosettifolia #3 x sericea.

A young blooming plant of P. 'Keystone's Harvest Moon'. While the flowers are produced on long pedicels, a trait I normally wound have culled out in a seedling, the yellow pigmentation of the leaves promises the beginning of some interesting foliar characteristics if I can get the plant to hybridize. One of my goals for hybridizing Petrocosmea is to introduce new, more ornamental foliage, since often Pets are entered in shows as "non-flowering" entries.

A close up shot showing the lavendar flowers of P. 'Keystone's Harvest Moon'. This color makes a lovely contrast with the yellow foliage which can be seen in the background.

A photo showing P. 'Keystone's Harvest Moon' on the right, beside a young plant of P. menglienensis, to show the yellow foliage color of 'Keystone's Harvest Moon'. The plant is NOT chlorotic. I have tested it with a number of leaf propagated plants and all show the yellow leaf color even in various conditions. Light intensity tends to affect the degree of yellow coloration, with higher light producing the most intense yellow coloring.

Thursday, November 5, 2009

The Three Petrocosmea minors - Part 3

A flowering plant of Petrocosmea minor veined leaf form. This form grows larger than any of the other forms, with heavier substance. Leaves and even flower petals show deeply incised veining along the central veins, lateral veins and even in between the lateral veins.

A close up photo the foliage of P. minor veined leaf form. Very glossy and bubbly in appearance, making quite an attractive plant in or out of flower. This form also seems to propagate the most quickly and readily from leaf cuttings and has the fastest growth rate of all the forms.

A close-up shot of the flower of P. minor veined leaf form, shows the recurved petals with the deep veining of the lower petals. Cymes are single to multiple flowered, with more branching of cymes on more mature plants. Cymes of this form have a sturydy, heavy substance.
The third form of P. minor in cultivation is the form now called P. minor veined leaf form. This form has been distributed as P. sp. '#5', P. sp. 'Chinese #5', and simply P. minor. It differs from the other forms most obviously in the deep veining of the large, heavy, glossy orbicular leaves. The petiole often has dense, quite long silvery hairs covering it, with these hairs being golden amber to brown near the base of the petiole. This form did succeed in a cross with P. sericea, using sericea as the pod parent. Seedlings of the cross can be seen in an earlier post on here a few days ago. The leaves of the seedlings do show the influence of P. minor veined leaf form, as they are all deeply veined even as small plants.

As new Petrocosmea species are collected and brought into cultivation, additional forms of P. minor are showing up. The plant pictured above was just collected and imported from China in late 2008 and appears to be another clone of, or at least very closely related to P. minor. I have small seedlings of this new form in my collection and am anxiously awaiting first flowers.
I hope that this discussion of the various forms of Petrocosmea minor is informative and helpful to enthusiasts and judges. Further study of these plants are causing me to be more and more certain that all of these plants are NOT truly P. minor. They differ from the published description in many significant ways. I feel more and more that these represent an undescribed species or "new" species to cultivation. Until this is confirmed, however, I recommend that plants be grown and labeled as we describe them here. Retaining the source of your plants is important. I try to keep records of the original labeling and source of all of my Petrocosmeas in the hopes that soon a taxonomist will provide come clarity to the labeling of these spectacular gesneriads.

Monday, November 2, 2009

The Three Petrocosmea minors - Part 2

A flowering plant of Petrocosmea minor pointed leaf form shows the smaller flowers, branched cymes or peduncles and smaller rosette size. Note the tips of the leaves on the leaves in the middle of the rosette have a pointed tip due to the margin of the leaf "rolling under" on each side. Once the leaves age, this tends to flatten out and the leaves take on a more rounded or orbicular shape.

The second form of P. minor to show up in cultivation in the US was the form now called "pointed leaf form". This name refers to a characteristic of the younger leaves to roll under at the margins near the apex of the leaf, causing a point to form at the tip. This form is often still exhibited as P. minor without any designation of the variety or form. This form differs from the smooth leaf form in several ways. The rosette tends to stay more compact or smaller in size. The growth rate is slower, for me. The color of the leaves is deeper green and the veining is slightly more prominently incised or "deeper" than with the smooth leaf form. Leaves are not as glossy as on the other two forms. Flowers are smaller, more cupped and have a large white throat. They are bluer in color than the more purple or violet color of the smooth leaf form. Petals are smooth with slight veining, although not as deeply veined as seen in the flowers of the veined leaf form. Lastly, the inflorescences, or peduncles are branched, with primary and secondary bracts. Calyx lobes are longer, there are still six of them, however, being longer, they form a "bell" around the bud, which in this form, tends to hang downward or droop on the inflorescence until just prior to opening.

Judges should note which form they are judging as the different characteristics might be viewed as culture flaws by the inexperienced judge. The pointed leaf form is the smallest of the three forms, is significantly slower to mature for me, and is not as glossy and shiny as the smooth leaf and veined leaf form. Also, in this form, the leaves do not lay as flat on the rosette, causing a more open and upright form to the rosette. These points could easily be attributed to poor or inconsistent culture resulting in a "stressed" plant by a judge, and therefore marked down in the scoring.

A flower of P. minor pointed leaf form.....note that it is smaller, and more cupped, with the calyx extending farther onto the upper lip. The white throat is more pronounced.

A cyme or peduncle from P. minor pointed leaf form. Not that there are primary bracts at the base of the first two branches and secondary bracts at the base of each calyx. The buds hang downward and the calyx lobes are longer forming a cup around the buds. Cymes are rarely ever single flowered, most always they are branched with three to five buds being typical.

Note the secondary bracts at the base of the calyx. This is the only form of P. minor to have this trait.

A close up of the center leaves of the rosette of P. minor pointed leaf form. In the early stages, leaves are more cordate in shape, with a pointed apex, but as they mature, they become more circular or orbicular in shape near the outer rows of the rosette. Leaves show deeply incised veins along the midvein and the lateral veins only.