264 NATURAL HISTORY OF PLANTS. 



species, with unequal sepals/ of which the genus Mitracarpum has 

 heen made.^ But the transverse scission takes place at variable 

 heights according to the species, and in some near the middle ; the 

 upper portion of the membranous pericarp rises as a lid, bearing 

 the calyx on the top. In other American species, generically dis- 

 tinguished under the name of Staelia,^ the line along which the 

 carpels open at maturity is not transverse but more or less oblique 

 from within outwards and from above downwards ; these plants are 

 thus intermediate between Mitracarpum and Spermacoce proper. In 

 other American and African species of Spermacoce, the cocci once 

 separated remain indehiscent like achenes ; of these have been 

 made the genera JDiodia^ and Dasijcephala.^ The former has as 

 many as ten divisions in the calyx and little prominent obtuse lobes 

 at the stigmatiferous portion of the style ; the axillary flowers are 

 generally few. The latter has four calycinal divisions, the two 

 style branches bristling with papillae, and the floral glomerules not 

 unfrequently disposed in spikes. S. filifolia, from western tropical 

 Africa, and a neighbouring species have been raised to the rank of a 

 genus (Octodon^), because the flowers united in false capitules of 

 glomerules, most frequently at the ends of the branches, are sur- 

 rounded by a pair of leaves forming an involucre to the inflorescence, 

 with connate stipules constituting a sort of dilated sheath ; w^hence 

 these annuals present a peculiar habit. 



Thus defined,^ this genus comprises about two hundred species.* 



* The largest are the lateral, described, in wide ciliate sheathlike stipules, and " solitary, 

 certain species, as lateral bracteoles of the flower axilate " flowers which we have not seen, 

 borne on its receptacle. ^ DC. Frodr. iv. 565 {Diodia sect. 2). — B. H. 



2 Zucc. Schult. Mant. iii. 210.— DC. Pvodr. iv. Ge)i. ii. 143, n. 315. 



571.— Endl. Gen. n. 3127.— B. H. Gen. ii. 146, o Thonn. et Schum. BesJcr. 74.- DC. Prodr, 



n. 323. — Staurospermtdn Thonn. et Schum. iv. 540.— Endl. Oen. n. 3119. — B. H. Gen. ii. 



Beskr. Guin. 73. 145, n. 320. 



3 Cham, et Schlchtl, Linncea, iii. 364, t. 3, ? Sect. 7 : 1. Euspermacoce (incl. Borreria) ; 

 fig. 3.— Rich. Rub. 71.— Endl. Gen. n. 3129. — 2. Staelia ; 3. Mitracarpum; 4. Diodia ; 5. Da- 

 B. H. Gen. ii. 148, n. 326. sycephala i 6. Octodon ; 7. Hypodematium. 



* L. Gen. n. 122.— J. Gen. 197.— G^rtn. Fr. » R. et Pav. FL Per. t. 91, 92.— H.B.K. Nov. 

 i. t. 121.— DC. Prodr. iv. 561.— Endl. Gen. n. Gen. et Sp. t. 278.— Miq. St. Surin. t. 51 {Bor- 

 3123.— B. H. Gen. ii. 143, n. 314. We refer, reria); FL Ind.-Bdt. ii. 330, 333 {Bigehvia) ; 

 with doubt, to Diodia, Hexasepalum (Bartl. ex Suppl. 550.— Benth. Fl. Hongk. 162; FL Aus- 

 DC. Prodr. iv. 561 ;— Endl. Gen. n. 3122 ;— B. traL iii. 438.— Harv. and Sond. FL Cap. iii. 25 

 H. Gen. ii. 145, n. 318), which has the narrow {Mitracarpum).— B\^. FL Maur. 158.— Thw. 

 (and still more elongate) leaves of IHodiay with Emm. Fl ZeijL 151.— Griseb. FL Brit. W.-Ind. 



