t 

 Anacharis. HYDROCHARIDACEJC. 129 



CLASS II. MONOCOTYLEDONOUS OR ENDOGENOUS PLANTS. 



Stems with the woody fibres scattered irregularly, not forming a separate zone 

 of annual woody layers between the bark and pith. Embryo with one cotyledon. 

 Leaves mostly parallel-veined, alternate, entire, and sheathing at base. Floral 

 whorls usually in threes. 



ORDER CIV. HYDROCHARIDACE-E!. 



Aquatic herbs, with dioecious or polygamous flowers in membranous spathes ; 

 regular 6-parted perianth, in two series (calyx and corolla), more or less tubular at 

 base; stamens 3 to 12 ; ovary inferior, 1 several-celled, with ascending ovules on 

 parietal placentae ; fruit indehiscent ; and seed without albumen. Distinguished 

 from the N~aiadacece and allied orders mainly by the inferior ovary. Perianth more 

 or less tubular at base. Staminate flowers usually several and pedicelled : stamens 

 distinct or united, the 2-celled anthers mostly introrse. Pistillate flowers usually 

 solitary : style single : stigmas 3 to 6, more or less deeply bifid. Fruit submerged, 

 a utricle or berry, usually many-seeded. Mostly perennials, with radical or in our 

 species opposite or whorled leaves. 



A widely distributed order, of a dozen genera and perhaps 30 species, very sparingly repre- 

 sented in North America, and especially so on the western coast. 



1. ANACHAKIS, Richard. WATER-WEED. 



Flowers polygarno-dioecious, solitary and sessile in an axillary sessile tubular 

 2-cleft spathe. Perianth small, in the sterile flowers with 3 scarcely united greenish 

 sepals and as many narrower petals ; in the pistillate flowers with a greatly elon- 

 gated filiform tube and a 6-parted spreading limb. Stamens 3 to 9, with short 

 filaments united at base ; anthers oval, or in the pistillate flowers oblong or want- 

 ing. Ovary 1 -celled, with 3 parietal placentae, few-ovuled. Style coherent with 

 the perianth-tube : stigmas 3, bifid or emarginate. Fruit a subglobose utricle. 

 Slender perennials, with elongated leafy branching stems, and numerous opposite or 

 whorled sessile thin 1 -nerved leaves; two or three temperate or tropical species. 



1. A. Canadensis, Planchon. Stems very slender and brittle, 1 to 4 feet 

 long, terete, rooting at the nodes : leaves dark green and pellucid, in threes or fours, 

 or the lower opposite, linear- or lanceolate-oblong, 3 to 6 lines long, acute, minutely 

 serrulate, sessile : tube of the perianth in the pistillate flowers 2 to 8 inches long ; 

 limb 1|> to 2 lines in diameter, greenish-purple; sepals concave; petals recurved: 

 stigmas long, terete, emarginate: utricle included within the small membranous 

 spathe, nearly a line in diameter, 4 - 6-seeded. Ann. & Mag. Nat. Hist. 2 ser. 

 i. 86. Elodea Canadensis, Michx. ; Caspary, Hydrill. 86 & 123. Udora, Nutt. 



In Mendocino County (Vasey) ; Oregon (Hall, Howcll) ; common in the Atlantic States, in 

 ponds and slow streams, and naturalized extensively in Europe. The staminate flowers, which 

 have rarely been noticed, are described as breaking from the stem and discharging their pollen 

 upon the surface of the water, to which the pistillate are raised by the elongated perianth-tube. 



