IlYDltoCHAinDACK.i:. ( KI{( m;'.S-I5IT FAMILY.) 41)') 



Class II. MOXOCOTYLEDOXOUS ok ENDOGENOUS 



PLANTS. 



Stems with no manifest distinction into bark, wood, and 

 pitli, but the woody fibre and vessels in bundles or threads 

 whicli are irregularly imbedded in the cellular tissue; pcrcii 

 nial trunks destitute of annual layers. Leaves mostly parallel- 

 veined (nerved) and slieathing at the base, seld(jm separatinL,^ 

 by an articulation, almost always alternate or scattered and 

 not toothed. Parts of the Howler commonly in threes. Em- 

 bryo with a single cotyledon, and the leaves of the plumule 

 alternate. 



Order 108. HYDROCHARIDACE^li:. (Froo's-bit Family.) 



Aquatic herbs, with dioecious or jfoli/f/amons regular Jlotcers, sessile or on 

 scape-like peduncles from a spat/ie, and simple or double Jiorul envelopes, 

 which in the fertile flowers are united into a tube and coherent icitli the 1 - 

 ^-celled ovary. Stamens 3-1 2, distinct or monadelplious ; anthers 2-eelled. 

 Stigmas 3 or 6. Fruit ripening under water, indehiscent, many-seeded. 

 Seeds ascending, without albumen ; embryo straight. 

 Tribe I. HYDKILLK^. Stem elongated, submerged, leafy. Spathes small, sessile. 



1. Klodea. Leaves verticillate (rarely oiiposite). Perianth-tube long-filil'orm. 



Tribe II. VALLISNEKIE^. Stemless. Leaves elongated. Spathes pedunculate. 



2. Vanisneria. Submerged ; grass-like. Fertile flower solitary on a verj' long scape. 

 Tribe III. STKATIOTE^E. Stem very short, with crowded leaves. Spathes pe- 

 dunculate. Ovary 6-9-cell<Ml. 



3. Liiunobium. Stemless, floating; broad leaves long-petioled. 



1. ELODEA, Michx. Water-weed. 



Flowers polygamo-dioecious, solitary and sessile from a sessile tabular 2-cleft 

 axillary spathe. Sterile flowers small or minute, with 3 sepals barely united 

 at base, and usually 3 similar or narrower petals; filaments short and unitcl 

 at base, or none; anthers 3-9, oval. Fertile flowers pistillate or apparently 

 perfect; perianth extended into an extremely long capillary tube; the liml) 

 G-parted; the small lobes ohovate, spreading. Stamens 3-9, often with im- 

 perfect anthers or none. Ovary l-celle»l, with 3 parietal placentse, each bear- 

 ing a few orthotropous ovules ; the capillary style coherent with the tube of 

 tlie perianth ; stigmas 3, large, 2-lobed or notched, exscrted. Fruit oblong, 

 coriaceous, few-seeded. — Perennial slen<ler submerged herbs, with elongated 

 branching stems, thickly beset with pellucid and veinless, 1 -nerved, sessile, 

 whorled or op])osite leaves. The staminate flowers (rarely seen) commonlv 

 break off, as in Vallisneria, and float on tlie surface, where thev expand and 

 shed their pollen around the stigmas of the fertile flowers, raised to the surface 



