ORDER 138—THE ORCHIDS. 285 
veined, entire, on long petioles. Scape 1-2f. high, branching in whorls, bearing nu- 
merous purplish-white flowers, in July. 
2. SAGITTA’RIA. Arrow-head. 
Flowers monecious, rarely dicecious, the ¢ with about 24 stamens, 
the ¢ with numerous ovaries crowded in a head, and becoming in fruit as 
many compressed, margined achenia.—2 Stemless plants, leaves radical, 
generally arrow-shaped. Flowers in whorls of 3's, the sterile ones above 
the fertile. 
S. variab’ilis. A curious plant, conspicuous with its large white flowers among the 
rushes and sedges of sluggish waters. The petals are wholly white, and the 
scape simple, with the stalks l-flowered. The leaves are generally arrow- 
shaped (as seen in the figure), but exceedinuly variable, sometimes lanceolate, 
and sometimes even consisting ofa petiole only. About lf. high. July. 
Orver CXXXVIII. ORCHIDACEH. The Orchids, 
Herbs perennial, with thick, fleshy roots; entire, parallel-veined leaves ; 
flowers very irregular, but the perianth consisting always of 6 parts, viz., of 3 
sepals and 8 petals, all usually colored, the lower petal called the 
lip differing in form from the others, and frequently spurred at base ; 
stamens 8, but only 1 or rarely 2 of them perfect, united with the 
style and forming what is called the column ; anthers 2, 4 or 8-celled; 
pollen powdery, or waxy, or granulated ; ovary 1-celled, many-seeded. 
Analysis of the Genera. 
* Stems green, furnished with one or more leaves....2 
* Stems green, furnished with sheaths instead of leaves.... 
* Stems brownish, furnished with sheaths and no leaves, or a late one....¢ ‘ 
2 Corolla lip very large, inflated and sack-like....a 
2 Corolla lip of various forms, but neither very large nor sack-like....8 
8 Corolla produced into a spur behind....b 
8 Corolla destitute of aspur....4 
4 Flowers small, many, in a loose raceme, beardless....¢ 
4 Flowers small, many, in a close, twisted spike, beardless....f 
4 Flowers showy, purple or yellow, few or 1 only....g 
a Root fibrous. Lip obtuse, spurless. Anthers2. Lady’s-siipper. Cyprire’prum. 1 
a Roota corm. Lip 8-lobed, 2-spurred. Anther 1. Calypso. CaLye’so. 
