Styrax rigidifolius forma yapobodensis Jdrobo 
& BR. Ie. Schultes forma nova. 
A Styrace rigidifolo foliis majoribus, marginibus rev- 
olutioribus, cum apice acuto non longe acuminato, supra 
opacioribus, subtus rufioribus ; alabastris minoribus ; caly- 
cibus grossiuscule quinque-sinuato-denticulatis; atque 
foliorum et calycum indumento asperiorio et rufiore 
differt. 
This forma appears to be an ecological adaptation to 
the extreme xerophytism of the sandstone mesa at Yapo- 
boda. An examination of the interesting plants collected 
at Yapoboda by Allen and a comparison of them with 
those of Mount Chiribiquete indicates that an even more 
severe xerophytism exists at the former than at the latter 
locality. As an example, the collection Allen 3190, ref- 
erable to Bombax coriaceum Mart. & Zuce. but with ex- 
traordinarily reduced leaves, may be cited. 
The differences enumerated above in the description 
of the form would, for the most part, seem to be related 
to adaptation to extreme xerophytism and radiation. 
Cotomata : Comisaria del Vaupés, | Cuduyari River], Yapobod4. ““Tree 
5m. Flowers white.’’ December 10, 1943, Paul H. Allen 8232 (Tyrr 
in U.S. Nat. Herb. 1951983). 
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