Monday, February 8, 2010

A Silky Haired Trio - The Petrocosmea sericea Group - II

In the last installment, I discussed the foliar characteristics of the trio of plants I call the "Sericea Group" due to the fact that they all share very similar foliar and floral characteristics. In addition, recent DNA data shows all three plants to be closely related to each other, so close, in fact, that they may be simply three unique individuals within the same species.

In this post, I would like to focus on the characteristics of the floral morphology. I'll start with the first plant to come into culitivation... the plant we currently grow as P. sericea.

The flower of P. sericea shows characteristics which clearly place the plant within Section Anisochilus, having shorter upper petals, one half the length of the lower petals. The flowers typically have five petals, with the shorter upper two petals being fused into a two lobed "hood" which bend forward over the pistil. The anthers cup together to form a "beak" with the pollen ejecting from the pointed tip of the "beak" when pressure is applied to the wider base of the anthers. P. sericea's flowers are usually born singly on the cyme, with a nice bluish lavendar color. At the base of the tube inside, is a darker purple spot. The petals on P. sericea are a bit longer and narrower in the lower portion of the corolla.
The cymes of P. sp. 'HT-2' are often multi-flowered...having from 1 to five flowers...most commonly two or three flowers. The petals on the flowers of this form are shorter and rounder at the lower portion of the corolla, giving a "fuller, rounder" look to the flowers when compared to P. sericea's flowers. Coloration is identical on the two forms.

The lower three petals of the flowers of P. sp. 'HT-2' are rounder and shorter than those of P. sericea, giving the flowers a fuller appearance. In this photo, you can barely see the darker purple spot at the base of the corolla around the ovary of the pistil.

While my own plant of P. sp. ? 'JR2008-1' has not yet flowered, this photo shows the plant from which my plant was propogated. The calyx lobes on this form appear hairier and more silvery, when compared to P. sericea and P. sp. 'HT-2', but the flowers otherwise appear nearly identical. Like P. sp.' HT-2' this plant appears to have multiple flowers on each cyme. This photo also shows the more open form of the rosette on this form and also that the leaves are softer adn have a less succulent nature than the other two forms in this group. The leaves are more pliable and softer to the touch.

A close up shot of the cyme and flower of P. sp. ? 'JR2008-1' shows the longer, more silvery calyx and cymes on this attractive feature in my opinion. I look forward to the flowering of my plant, which so far, has been slow to flower.
While the flowers are very similar, there are key differences which allow each form to be identified as unique in it's own right. Still, I feel these are all representative of the same species. Time will tell.
There is one last installment in this series....... Should Petrocosmea cavaleriei be included in the "Sericea Group"?