Very close isn't it? I think so. Morphologically, the flowers and foliage of the plant I acquired last year labeled P. cavaleriei are so very close. I have sent plant material to have it's DNA studied in relation to the DNA of the other three, but do not yet have results. Hopefully those will come soon. But, independent of the DNA data, I feel this plant belongs to the same group as the other three. It does not totally match the published description of P. cavaleriei, but then neither does P. sericea.....or most other Petrocosmeas which currently bear a name. Again, the identity crisis for this genus.
The flowers of P. cavaleriei closely match those of P. sericea and the others in the "Sericea Group". It clearly fits within the Section Anisochilus, as do the other three plants. Other than form of the petals, it is identical. 
Petrocosmea cavaleriei pictured above, looks very much like P. sericea, and P. sp. 'HT-2'...especially the latter. It differs only in it's small stature. This plant stays small, after two years, this plant still remains in a three inch pot. Cymes are single flowered. I'm anxiously awaiting the DNA results to see how closely it is related to the others in this group.
I thought I would conclude by showing a bit of what P. sericea is capable of as a parent in hybridizing. My very first hybrid, pictured above, is the result of a cross using P. sericea as the pollen parent with P. rosettifolia #3. The hybrid was named for a dear friend, P. 'Rosemary Platz'. It inherited a heavier leaf substance, the leaf shape, and size from P. sericea. Flower size and coloration on this hybrid also show the influence of P. sericea. The serrated leaf edges, the glossy green leaf color with lighter yellowish veins clearly came from the P. rosettifolia parent. 
A close up of the flower of P. 'Rosemary Platz' shows a nice lavendar color from P. sericea, while the absence of the dark purple blotch at the base of the tube, along with the two yellow stipes are from the P. rosettifolia parent. Flower size is similar to P. sericea.
A trio of first flowers from three seedlings resulting in my second P. sericea cross. This time P. sericea was the seed parent with pollen coming from P. minor veined leaf form. The variation in the purple color of the flowers shows the lightest being the color of P. sericea and the darkest coming from the deep purplle of P. minor. Two flowers have the white throat of P. minor, while the one on the left has no white in the throat...which is most like P. serice. All three inherited the deep purple blotch at the base of the corolla, which both parent have. Genetically, P. minor and P. sericea are closely related to each other. None of these seedlings have been named as yet, but the three pictured are held for another years growth to evaluate their perfomance as they mature. While P. sericea can be slow to mature, these three all bloomed as tiny plants in one ounce pots.... each seedling flowered with fewer than ten leaves.
