30 NATURAL HISTORY OF PLANTS. 



at their apices, surmount the ovaries. The fruit, accompanied 

 at its base by the persistent calyx, is composed of two orbicular 

 compressed achenes, smooth or rugose, touching each other 

 within by a flat surface, but separating easily. Their thick solid 

 pericarp hollowed by vacuoles, thinner within where there are 

 apertures (figs. 37,38), encloses a vertical seed (figs. 39, 40); 

 its membranous coats covering an annular embryo with inferior 

 radicle, enveloping a farinaceous albumen. Limeum consists of 

 annual or perennial herbs of Asia and tropical Africa, The 

 leaves are alternate, narrow, simple, entire or ciliate, and exstipulate. 

 The flowers are arranged in axillary or subterminal cymes some- 

 times united in racemes of terminal cymes, when bracts replace 

 the ordinary leaves at the apex of the branches. Ten species have 

 been described. 1 With the same vegetative organs and floral 

 organization, Semonvillea? of which one Cape species is known, and 

 another of Western Tropical Africa, has been taken for the type of 

 a particular genus, because the edges of the achenes expand into 

 an orbicular wing, transforming them into samaras. We only make 

 it a section of the genus Limeum. 



II. BAEBEUIA SEEIES. 



Barbaric? (figs. 41-43) has regular, hermaphrodite, apetalous 

 flowers. Upon the slightly convex receptacle are inserted five 

 sepals, a little unequal as to size and thickness, and arranged in 

 quincuncial prefloration in the bud. More internally, upon the 

 slightly projecting ring of the receptacle are inserted an indefinite 

 number of stamens, each formed of a free filament and a bilocular, 4 

 introrse, sagittate anther, dehiscing by two longitudinal clefts. The 

 gynseceum is free and superior, formed of a bilocular 5 ovary, sur- 



1 Fe>zl, in Ann. Wien. Mv.s., i. 341. — Hart. Gen., n. 6843. — H. Bn., in Adansonia, iii. 312 

 et Sond., Fl. Cap., i. 152. t. 6. 



2 J. Gat, in Bull. Feruss., xviii. 412. — Endl., a Its cells are independent at their two ex- 

 Gen., n. 5259. — Fenzl, in Dec. Mus. Vindob., n. tremities. 



48. — MOQ., Prodr., xiii.p. 2, 19. — Hook., Icon., 5 The separating partition of the cells dc- 



t. 587. — B. H., Gen., 859, n. 21. scending from the apex of the ovary to its hasp, 



3 Dtjp.-Th., Gen. Nov. Madag., 6. — Endl., does not here adhere to the ovary wall. 



