;^70 NATURAL HISTORY OF PLANTS. 



nate, stipulate, i^laiidular, tripinnatisect, with very numerous 

 j)innules, t^'landular at their apices. The flowers, accompanied by 

 ^,'landular bracts, are collected into little cymes terminating the 

 branches. 



Pi/rshia' in habit and foliage nearly resembles Coioania, and not 

 certain species oi Pol en fill as as is the case with Chamoihatia ; still the 

 flowers are very like those of the last-named genus : the same 

 perianth, the same external capitate hairs, the same gynseceum, with 

 its peculiar stigma formed of papillse scattered over the everted 

 lips of the longitudinal groove of the style, the same ovule with 

 its ventral raphe and its interior dorsal micropyle. The sepals 

 and petals are imbricated in the bud, and the dry fruit, partly sur- 

 rounded by the hardened receptacle, contains a single seed with 

 thin albumen and an erect embryo whose radicle is inferior/ But 

 the androceum of PursUa contains a far lower number of stamens ; 

 there are usually only from twenty to thirty ; the receptacle on 

 whose edges they are seated is much more elongated, like a cornet 

 or a narrow funnel ; and the alternate leaves are small, serrate, 

 simple, and cuneiform, or tridentate, trifid, or even pinnatifid, with 

 two little adnate stipules at the base of the petiole. The only known 

 species,^ which grows in the Eocky Mountains, has the appearance 

 of a little much-branched Cotoneaster. Its flowers are sessile, axillary 

 and terminal. 



Cercocarpns* (figs. 436, 437) also consists of shrubs or under- 

 shrubs, in habit and foliage recalling certain species of Coioania. 

 The hermaphrodite flowers are constructed on the same general 

 type as in the two preceding genera ; the gynseceum, too, is reduced 

 to a single carpel whose ovary contains a single nearly basilar ovule, 

 with its raphe ventral. But there are no petals, and the receptacle 

 presents considerable modifications in the conformation of its 

 ditk'vcnt parts. It is like a narrow vase, much elongated, and 



' DC, Tranx. Lhin. Soc, xii. 157 ; Prodr., ii. is exceptional in the FragariecE, would seem to 



541.— Hook., Fl. Bor.-Amer., i. 170, t. 58.— bring Purshia near certain Spireea. 



LiNOL., Bol. Reg., t. 1446.— Endl., Gen., n. 3 p tridentata DC, loc. eit. — Tigarea tri- 



6380.— ToRK. & Gn., Fl. N. Amer., i. 428.— dentata PtJESH. 



B. H., Oen., 617, n. 37.— Tigarea PuESH., Fl. * H. B. K., Nov. Gen. et Spec, vi. 183, t. 



.V. Amer.,\. 333, t. 15 (ncc Atjbl.).— iTwjjzJa 559.— DC, Prodr., ii. 589 — ToEK. & Ge., -FZ, 



Sl'KEXO., Syst. Veg., ii. 475 (nee Keich.). N. Amer., i. 427.— Hook., Icon., t. 322-324.— 



* The testa is thick, blackish, and shining, Enpl., Gen., n. 6381.— B. H., Gen., 618, n. 40. 



and almost 8iK)npy internally. Bentham k —Bertolonia Sess. & Mo<^., ex DC, loe. cit. 



HooKF.K remark that this organization, which (nee Speeng., nee Radd.). 



