684 SYSTEMATIC EOTANY. 



Virginia. Mayaca is the only genus, of which there are 4 

 species. Their properties and uses are unknown. 



Natural Order 264. CoMMELYNACEiE. — The Spider- Wort 

 Order. — Character. — Herbs with flattened narrow usually 

 sheathing leaves. Perianth inferior, more or less irregular, in 6 

 parts arranged in two whorls ; the outer parts being green, per- 

 sistent, and opposite to the carpels ; the inner petaloid. Stamens 

 3 or 6, some generally abortive, hypogynous ; anthers 2-celled, 

 introrse. Ovary 3-celled, superior; style 1. Capsule 2 — 3- 

 celled, 2 — 3 valved, with loculicidal dehiscence and axile pla- 

 centation. Seeds few, with a linear hilum ; embryo shaped like 

 a pulley, remote from the hilum, in dense fleshy albumen. 



Distribution, cfr. — They are chiefly natives of India, Africa, 

 Australia, and the West Indies. Examples of the Genera : — 

 Commelyna, Tradescantia. There are above 260 species. 



Properties and Uses. — Their properties are unimportant. The 

 rhizomes of some species, as those of the Commelyna tuberosa, 

 C. angustifolia. and C. striata, contain much starch, and when 

 cooked are edible. Some species have been reputed astringent 

 and vulnerary, and others emmenagogue, &c. 



Natural Order 265. Xyridace^I!;. — The Xyris Order. — 

 Character. — Sedge-like herbaceous plants. Leaves radical, 

 sheathing, ensiform or flliform. Flowers perfect, in scaly heads. 

 Perianth inferior, of 6 parts arranged in two whorls, — tlae outer 

 glumaceous, distinct, and opposite the carpels ; the inner peta- 

 loid, and united. Stamens, 6, 3 being fertile and inserted on the 

 petaloid perianth ; anthers extrorse. Ovary superior, 1 -celled, 

 with parietal placentas. Capsule 1 -celled, 3 -valved. Seeds 

 numerous, orthotropous ; embryo minute, on the outside of fleshy 

 albumen. 



Distribution, <^-c. — Exclusively natives of tropical and sub- 

 tropical regions. Examples of the Genera: — Xyris, Kapatea. 

 There are about 70 species. 



Properties and Uses. — Unimportant. The leaves and roots of 

 some species of Xyris have been employed in cutaneoiis affections. 



Natural Order 266. Philydeace^. — The Water-wort Order. 

 — Character. — Herbs with fibrous roots. Leaves equitant, 

 ensiform, sheathing. Flowers surrounded by spathaceous per- 

 sistent bracts, solitary. Perianth inferior, in 1 whorl, 2-leaved, 

 petaloid. Stamens 3, 2 of which are abortive ; filaments united. 

 Ovary superior, 3-celled, with axile placentas. Fruit a loculi- 

 cidal capsule. Seeds numerous, with an embryo in the axis of 

 fleshy albumen. 



Distribution, cfc. — They are natives of China, Cochin China, 

 and New Holland. There are 2 genera, Philydrum and Hetaeria, 

 and 2 species. Their properties and uses are unknown. 



Natural Order 267. Jtjkcacbje. — The Eush Order {figs. 

 1053 and 1054). — Sedge or grass-like herbs, with tufted or 



