252 NAJADACEiE. Ruppia. 



3. RUPPIA. Linn. ; Endl. gen. 1661. DITCH-GRASS. 



[Named in honor of Henry Bernard Ruppids, a German botanist.] 



Flowers perfect, 2 or more on a spadix, naked. Stamens 2, opposite : anthers large, peltate, 

 clasping the spadix, 2-celled ; the cells parallel, disjointed, opening horizontally by two 

 valves : pollen elongated, curved, with three protuberances. Ovaries mostly 4, at first 

 sessile, stipitate in fruit : stigma sessile, peltate. Ovule pendulous, campulitropous. Fruit 

 drupaceous, on long pedicels, obliquely ovoid, more or less beaked ; the endocarp thin and 

 crustaceous. — A floating herb, growing in salt or brackish water, with slender branching 

 stems and linear entire leaves. Flowers on a spadix, which is at first short and included in 

 the sheathing spathe-like base of a leaf, but finally becomes much elongated. 



1. Ruppia maritima, Linn. Ditch-grass. 



Linn. sp. 1. p. 127 ; Hook, in fl. Lond. t. 50 ; Michx. Jl. 1. p. 102 ; Pursh, fl. \. p. \2\ ; 

 Ell. sk. 1. p. 581 ; Bigel.ji. Bost. p. 64 ; Torr. compend. p. 89 ; Beck, hot. p. 385 ; Hook. 

 Jl. Bor.-Am. 2. p. 170 ; Kunih, enwn. 3. p. 123. 



Perennial. Stems of variable length. Leaves linear-setaceous, alternate, 1-3 inches 

 long, much dilated and sheathing at the base. Spadix included in the transparent sheath, at 

 first sessile, but in fruit elevated on a filiform peduncle which is from 2-6 inches long. 

 Flowers 2 on each spadix, consisting of 2 sessile anthers each of which is 2-celled, or, 

 according to others, of 4 one-celled anthers, surrounding 4 minute sessile ovaries. Anther- 

 cells roundish, opening transversely by 2 hemispherical valves. Ovaries very minute, usually 

 4, but sometimes 3 or 5. After flowering, the base of the spadix elongates, and supports the 

 fruit on slender pedicels. Drupes olive-green, smooth, acuminate with a siiort oblique beak. 

 Epicarp thick and crustaceous, black. 



In saltwater bays and ditches : common in tlie neighborhood of New-York and on Long 

 Island. June - August. 



4. ZANNICHELLIA. Michx. ; Endl. gen. 1662. HORNED pondwebd. 



[In honor of John Jerome Zannichelli, a Venetian botauist.] 



Flowers monoecious, naked, without bracts. Sterile flowers consisting of a single stamen : 

 filament slender : antlier of 2 oblong parallel cells ; tlie connective produced at tlie summit. 

 Fertile flowers consisting of 2 - 4 sessile jiisvils, arising from a cnpshaped sheath, tapering 

 upward into a short style : stigma large and disk-form. Ovule pendulous, orthotropous. 

 Fruit on a short stipe, obliquely oblong, rostrate, somewhat coriaceous. — A submersed 

 aquatic herb, with a branching slender stem, narrow linear entire leaves, and solitary 

 axillary flowers. 



