rigidifolius. Styrax rigidifolius would not seem to be 
closely allied to any known species, but it approaches 
most closely 8. ambiguus Seub. of southeastern Brazil. If 
we are to judge from the description and a photograph 
of the type, Styrax ambiguus is very similar vegetatively 
to S. rigidifolius in having rather coriaceous or thick- 
papyraceous leaves of a small size with revolute margins, 
characters not common in the genus. There are, how- 
ever, very appreciable differences in the size of the flower, 
the texture and indumentum of the calyx, the shape and 
size of the corolla lobes, the shape and size of the sta- 
mens, the pilosity at the point of union of the filaments 
with the corolla tube, and the form and pilosity of the 
ovary. 
Styrax rigidifolus belongs to the section Mustyraa, 
series Valvatae. In the key to the species in Perkins’ 
monograph (Pflanzenr. [V, 241 (1907) ), the specimen 
which is here described as new traced out to the vicinity 
of Styrax calvescens Perk., an East Indian species with 
no relationship to S. rigidifolius. 
Styrax rigidifolius [drobo & R. I. Schultes sp. nov. 
Frutex parvus, usque ad octo pedes altus. Rami te- 
retes, cortice griseo, Juniores fusco-pulverulenti, demum 
glabrescentes, usque ad 5-6 mm. in diametro. Folia peti- 
olata, oblongo-elliptica, longe acuminata, apice ipso acu- 
ta, basi subrotundata vel saepe rotundato-cuneata, rigide 
coriacea, integra, fusco-pulverulenta, maturitate 6-7 cm. 
longa, 2.3-8 cm. lata, margine valde revoluta, supra gla- 
bra (ochraceo-viridia in siccitate) vel in nervo centrali 
basim versus paulo sordide pulverulenta, nitida, subtus 
cinnamomea, juniora rufidula, dense et molliter praecipue 
nervos versus tomentosa, pilis albis minutissimis stellatis 
remotius brunneis cum pilis aloéformibus intermixtis ves- 
tita, supra nervo centrali immerso, subtus valde elevato, 
[ 328 ] 
