310 PLANTS NOV^ THUBBERIAN^. 



HOLACANTHA, Nov. Gen. Simarubacearum. 



Flores abortu dioici. Masc. Calyx brevis, 7-8-partitus, lobis in alabastro juniore 

 imbricatis. Petala 7-8, hypogyna, oblonga, concava, sestivatione imbricata, cito de- 

 cidua. Stamina 12-16, ssepius numero petalorum dupla, margini 12- 16-crenato 

 disci clypeati vel subcyathiformis inserta, brevia: filamenta inappendiculata, crassa, 

 fusiformia, gibbosa, villosissima : antherse oblongse, biloculares, basifixse, introrsse, mox 

 deciduse, loculis longitudinaliter dehiscentibus. Ovarii abortivi vestigium parvum in 

 fundo disci. Foem. Calyx et corolla % maris. Stamina abortiva 7-8, filamentis subu- 

 latis villosis, antheris inanibus. Ovaria ssepius 6, gynophoro brevissimo imposita, 

 conniventia, basi tantum mediante columna centrali brevissima connata, uniovulata : 

 styli totidem terminales, ima basi subcoaliti, deinde radiato-divergentes, intus prorsus 

 stigmatosi. Ovulum semianatropum, sutura ventrali infra medium insertum, adscen- 

 dens, micropyle tenui supera, Drupse siccee 4-6, sessiles, stellatse, ovatse, demum e 

 carpophoro brevi 4 - 6-fido secedentes ; epicarpio tenui ; putamine crustaceo Isevi. 

 Semen ovatum, acuminatum ; testa tenui ; rhaphe brevissima. Embryo intra albumen 

 carnosum parcum ; cotyledonibus obovatis planis subfoliaceis ; radicula breviuscula 

 supera. — Frutex orgyalis, aphyllus, spinis validis horridus ;, ramis adscendentibus ; 

 floribus parvis secus ramulos spinescentes glomeratis. 



HoLACANTHA Emoryi. — On the desert between the Gila Eiver. and Tucson ; and on 

 the table-lands near the river Salinas, north of the Gila (the latter in July, 1852, in 

 flower.) — Shrub 5 to 8 feet high, leafless, so far as known ; but the ascending branch- 

 lets furnished with a few small and alternate, oblong or linear, entire scales or bracts, 

 of a line or two in length, which are soon deciduous. The wood of the branches is 

 moderately hard ; the bark smooth and light green, on the younger parts cinereous 

 with a close and soft pubescence. The alternate, terete, and rigid branehlets are all 

 produced into stout and sharp thorns. Flowers apparently dioecious (at least the male 

 and female flowers occur on different specimens in the collection), glomerate on the 

 sides of the branehlets, which they sometimes nearly cover, so as to form a kind of 

 spike or spiciform thyrsus, subsessile or occasionally on short pedicels. Male. Flower- 

 buds globose-oblong, a line and a half in diameter ; both the calyx and the corolla ca- 

 nescently pubescent externally. Sepals 7 or 8, about half the length of the corolla in 

 the full-grown flower-bud, triangular-ovate, united at the base. Petals as many as the 

 sepals and alternate with them, imbricated in the bud, when they are concave and 

 somewhat carinate, their margins and inner surface apparently greenish-white, inserted 



