The Natural System of Botany. 363 



gens by their herbaceous green sepals. Ex. : Tradescantia 

 (Spider-wort), Commelyna. 



Xyridace^e. The Xyris Tribe. Resembling the rushes 

 m aspect. Flowers, capitate. Ex. : Xyris (Yellow-eyed grass.) 



Eriocaulonace,e. The Pipe-wort Tribe. Aquatic herbs, 

 with cellular leaves, and heads of minute flowers. Ex. : Erio- 

 caulon (Pipe- wort.) 



Division IT. — Glumace-s:. 



Flowers, destitute of a true calyx and corolla, but enveloped 

 in scales or chaffy bracts. This division comprehends the 

 grasses and sedges. 



Cyperace.e. The Sedge Tribe. This is a large order of 

 coarse, grass-like plants, with fibrous roots, stems without joints, 

 and solid. They are natives of nearly all countries, but in 

 general possess few useful properties. The ancient papyrus 

 was made of the pith of Cyperus Papyrus. Ex. : Scirpus 

 (Club-rush, &c), Carex, Eriophorum. 



Gramine^. The Grass Tribe. One of the largest, most 

 common, and most important orders. The stems are hollow, 

 and jointed ; the leaves entire, parallel veined, sheathed at 

 base ; flowers in spikelets, racemes, or panicles. The grasses 

 undoubtedly contribute more sustenance for both men and 

 animals than all the rest of the vegetable kingdom. With a 

 single exception, no poisonous plant is known to be contained 

 in the order. The stems often contain sugar, and the fruits 

 are the common grains, as wheat, rye, oats, barley, &c. Ex. : 

 Poa, Alopecurus, Festuca Panicum, Phleumi Agrostis, &c, 

 which are among the most common pasture grasses ; Triti- 

 cum (Wheat), Zea (Maize), Avena (Oat), Hordeum (Barley), 

 Secale (Rye), &c, which afford the staple food of men ; Sac- 

 charum (Sugar-cane), Sorghum (Broom-corn), &c. 



Flowerless, or Cryptogamous Plants.' 



Plants chiefly composed of cellular tissue, destitute of spiral 

 vessels, having no flowers, and instead of seeds, producing 

 spores. 



The flowerless plants are divided into the following orders, 



