264 NATURAL HISTORY OF PLANTS. 



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

 been 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 obUque 

 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 Diodia^ and Dasycephala.^ 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 ; whence 

 these annuals present a peculiar habit. 



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



' The largest are the lateral, defcrlbed, in wide ciliate sheatMike stipules, and " solitary, 



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



home on its receptacle. = DC. Piodi: iv. 665 (Diodia sect. 2). — B. H. 



^ Zdoc. Schult. Mant. iii. 210.— DC. Prodr. iv. Gen. ii. 143, n. 315. 



671.— Endl. Gen. n. 3127.— B. H. Gen. ii. 146, « Thonn. et Schdm. Seslcr. 74.— DO. Prodr. 



n. 323. — Stnurospermmn Thonn. et Sohum. iv. 540.— Endl. Gen. n. 3119. — B. H. Gen. ii. 



Beshr. Guin. 73. 14,5, n. 320. 



3 Cham, et Schlchtl, Limaia, iii. 364, t. 3, ? Sect. 7 : '1. Euspermaeoce (incl. Bor^eria) ; 

 fig. 3.— Rich. Hub. 71.— Endl. Gen. n. 3129. — 2. Staelia ; 3. Mitracarpum; 4. Diodia ; 6. Da- 

 's. H. Gen. ii. 148, n. 326. sycepTiala; 6. Octodon ; 7. Sypodonatium. 



* L. Gen. n. 122.— J. Gen. 197.— Gjektn. Fr. » E. et Pav. Fl. Per. t. 91, 92.— H.B.K. Nov. 



i. t. 121.— DC. Prodr. iv. 661.— Endl. Gen. n. Gen. et Sp. t. 278.— Mia. St. Surin. t. 61 (Bor- 



3123.— B. H. Gen. ii. 143, n. 314. We refer, reria); Fl. Ind.-Bat. ii. 330, 333 [Bigelovia) ; 



with douht, to JDiodia, Hexasepalum (Baktl. ex Suppl. 660.— Benth. PI. Hongk. 162; Fl. Aus- 



DC. Prodr. iv. 561 ;— Endl. Gen. n. 3122 ;— B. tral. iii. 438.— Harv. and Sond. Fl. Cap. iii. 26 



H. Gct. ii. 146, n. 318), which has the narrow {Mitracarpum). — Bak. Fl. Maur. 168. Thw. 



(and still more elongate) leaves of Diodia, with JS«m;«. PI. Zeyl. 151.— Grisee. Fl. Brit. W.-Ind. 



