142 



NATURAL HISTORY OF PLANTS. 



Trachymene (fig. 162-164) belongs to a sub-series in which the 

 fruit is also compressed perpendicular to the partition, but differs 

 widely from Hydrocotyle in habit, and the leaves are without stipules. 

 The flowers of Trachymene are in simple umbels (more or less capituh- 



Trachymene carulea. 



Fig. 162. Flower (4). 



Fig. 163. Long. sect, of flower. 



Fig. 164. Fruit. 



Xanthosia rotundifolia. 



form) and with an involucre of numerous bracts free or united at the 

 base. The calyx is wanting, or the five sepals or some of them are 



more or less developed, and the petals, en- 

 tire, unequal, are imbricate in vexiUary 

 prefloration. The fruit is much flattened 

 laterally and the two mericarps are rarely 

 equal. The anterior may be almost entirely 

 . aborted and remain sterile ; or rather it 

 differs in form, appearance and superficial 

 condition from the posterior carpel which 

 contains first an ovule, then a seed with 

 narrow aliform raphe. Trachymene inhabits 

 Oceania, especially Australia, and consists of 

 herbs often annual, with branches sometimes 

 leafiike. Xanthosia and Siehera, also Austra- 

 lian, resemble the above especially in the flattened fruit. In the 

 former (fig. 165) the sepals are well developed, wide, cordate, bilobed 



Fig. 165. Flower (|). 



7c. Fl. Germ, t.- 1 842.— Harv. et Sond. Fl. Cap. 

 ii. 526.— Hook. p. Fl. Tasm. 32, 33; Handb. 

 N.-Zeal. Fl. 85.— Benth. Fl. Austral, iii. 337. 

 — Wedd. Chlor. And. ii. 188. — A. Gkay, Man. 

 (ed. 5) 189.-CHAPM. Fl. S. Unit. St. 158.— 

 MoLKB. Fl. Jungh. i. 89.— Thw. Enum. PI. Zeijl. 



130.— 0. Gay, Fl. GUI. iii. 62, 69 {UwropUurd). 

 — MiQ. Ann. Mus. Lugd.-Bat. iii. 55. — Boiss. 

 Fl. Or. ii. 820.— Gren. et Godr. Fl. de Fr. i. 

 751.— Walp. Sep. ii. 381 ; v. 838 ; Ann. i. 339, 

 977 ; ii. 690 ; v. 58. 



