ORCHID ACE^I. 515 



Some are mucilaginous and astringent. Vallisneiia spiraUs (fig. 228) 

 is a dioecious plant, the male flowers of which, at the time of flower- 

 ing, are said to be detached from the mud of the water in which 

 they grow, and to float on the surface. At the same time the female 

 flower developes a long spiral peduncle, by .means of which it reaches 

 the surface of the water, so as to allow the application of the pollen 

 (T 496). The order has been divided into two sections: 1. Vallis- 

 neriea3, ovary 1 -celled. 2. Stratioteae, ovary many-celled. There are 

 12 known genera, according to Lindley, including 20 species. Exam- 

 ples Vallisneria, Udora, Anacharis, Stratiotes, Hydrocharis. 



1056. Order 185. Orchidacete, the Orchis Family. (Mono-epigyn.) 

 Flowers bisexual. Perianth adherent, herbaceous, or coloured, with a 

 6-partite limb (fig. 736 pe, pi), the segments being arranged in 2 

 rows; exterior row (fig. 735 ce), called the calyx (although Lindley 

 says it is more properly the corolla, the true calyx or calyculus being 

 usually abortive), consisting of 3 segments (rarely 2 by adhesion), the 

 odd one of which is often next the axis by a twisting of the ovary ; 

 interior row (fig. 735 c z), called the corolla (regarded by Lindley 

 as petaloid stamens), consisting usually of 3 segments (very rarely 1), 

 the odd one of which is called the labellum or lip. This labellum 

 (figs. 735, 736, 737 /) frequently differs from the other divisions of the 

 perianth, assuming remarkable forms, being lobed, spurred at the 

 base, or furnished with peculiar appendages, which are sometimes 

 derived from the stigma. It is sometimes divided by contraction, so 

 as to exhibit three distinct portions, the lowest being the hypochilium 

 (tfTt-o, under, and %ifaos, lip); the middle, mesochilium (fttao;, middle); 

 and the upper, the epichUium (l?r<, upon or above). Stamens 3, epi- 

 gynous, united in a central column along with the style; jthe two 

 lateral stamens are usually abortive (fig. 736 ss), the central one oppo- 

 site the odd exterior segment being fertile (fig. 736 e); but at times 

 the two lateral are fertile, and the central one is abortive; anthers 1-2- 

 4-celled (fig. 738); pollen powdery or cohering in definite (fig. 744) 

 or indefinite waxy masses (pollinia) (figs. 739, 743), which often ad- 

 here by a caudicle (fig. 743 c) to a gland connected with the beak 

 (rostellum) of the stigma. This gland is sometimes naked, at other 

 times in a sac or pouch (bursicula). Ovary adherent, 1-celled (fig. 

 740), composed of 6 carpels, of which 3 only are placentiferous (Lind- 

 ley); style incorporated with the column (gynostemium, -/wn, pistil, 

 and artifcav, stamen); stigmas a viscid hollow space in front of the 

 column (fig. 737 s), communicating directly with the ovary by an open 

 canal. The upper part of the united stigmas is often extended into a 

 beak-like process (rostellum). Placentas 3, parietal (figs. 457, 740). 

 Fruit a capsule, opening by 3 or 6 valves, rarely fleshy, and indehis- 

 cent. Seeds 00, very minute, with a loose reticulated spermoderm 

 (fig. 741), exalbuminous ; embryo solid, fleshy (fig. 742); large radicle 



