368 



NATURAL HISTORY OF PLANTS. 



Dryaa 

 octopetala. 



calyx and corolla consist of eight or nine leaves apiece ; the achenes 

 are sessile, and the solitary flowers are borne on erect terminal 

 peduncles. Only two species are known, from arctic, 

 alpine and temperate districts of the northern hemi- 

 sphere ;' they are undershrubs, with pretty thick stems, 

 which rise to no great height, but are usually prostrate 

 and ramified, bearing short branches with alternate, 

 simple, very polymorphous leaves, possessing two lateral 

 petiolary stipules. 



Cowania and Fallugia have also the sessile achenes 

 surmounted by long feathery styles of Dryax or Sieversia ; 

 but have quite different vegetative organs. They are 

 true erect very bushy shrubs, found in North America, 

 Mexico, and California. Cowa/iia," of which three 

 species have been described, has hermaphrodite or poly- 

 gamous flowers with the receptacle of Jiosa, covered 

 externally, like the calyx, with capitate glandular hairs ; 

 five unequal quincuncially imbricated sepals, and five im- 

 bricated petals alternating with these; and a large number 

 of stamens inserted in the throat of the receptacle, 

 above the thick edge of a glandular disk lining the inside 

 of the sac. The carpels are five in number, or more 

 frequently indefinite, inserted in the bottom of the 

 receptacular sac, and each containing an erect ovule. 

 Each fruit contains a seed with a fleshy embryo, sur- 

 rounded by a thin layer of albumen. The flowers are 

 solitary and sessile, terminating the short branches 

 which are covered by numerous alternate leaves, each 

 of which possesses two lateral petiolary stipules entire, 

 or more or less deeply notched or lobed. FaUut/ia^ 

 of which only one species is known, has the calyx of Cowmna, 



ovary contaiim one ovuk' which \% incompletely 

 uiialrojwuH, no that its liiluiii is lii^lii-r u]) tliuii 

 it« inicropyle ; it Iki.h only one coat. TlicHtipnu- 

 tifonniH extremity of tliu Htylt- ih warcely diluted. 



' Hook., Kxut. Flur., t. T20 ; Jiut. Ma,/., t. 

 2i)72.-(JuE.v. & (JoDU., /v. ,lf Fr., 1. ^iH.— 

 Walp., Rep., ii. 49 ; Ann., i. im. 



^ Don, TranM. Linn. Sue, \\\. VI \, t. 22, 

 figH. ]-(>. — Km)I.., Gen., n. (JSR?. Swkict. 



Brit. Ft. Oard., sor. 2, vii. t. 400.- Tokk. A 

 Gu., ap. n'ippl. Erpi-d., l(Vt(2S). -I?. 11.. Om., 

 filH. n. ^\.— Oreggia E.nqklm., Hot. H'itliz. 

 Exped., 30, not. 



' Knui,., Gi-h., n. 0385.— ToKU., Emor. Sep., 

 t. 2. -Touu. & (}tt.,np. nippl. Exped., 164 (2«). 

 — H. H., Gen., (\\H, n. 43. — Sieversia para, 

 doxa Don, Tirana. Linn. Soc., xiv. 57G, t, 22, 

 fiff.7-10. 



