JUXCAGINACEAE (ARROW GRASS FAMILY) 79 



and contai.-I.ig a tuft of threads in place of ordinary pollen ; the fertile of single 

 ovate-oblong ovaries attached near their apex, tapering upward into an awl- 

 siiaped siylf, and containing a pendulous orthotr()i)Ous ovule ; stigmas 2, long 

 and bristie-form. deciduous. Utricle bursting irregularly, inclosing an oblong 

 iongitudinally ribbed seed (or nutlet). Embryo short and thick (proper cotyle- 

 don almost obsolete), with an open chink or cleft its whole length, from which 

 protruiies a doublj'^ curved slender plumule. — Grass-like marine herbs, growing 

 wluilly under water, from a jointed creeping stem or rootstock, sheathed by the 

 bases of the very long and linear obtuse entire gras.s-like ribbon-shaped leaves 

 (wiience the name, from ^cjaTrjp, a belt). 



1. Z. marina L. Leaves obscurely 3-5-nerved. — Shoal water of bays along 

 the coast, Nfd. to Fla. ; Pacitic coast. (Eurasia.) 



6. NAJAS L. Naiad 



Flowere dioecious or monoecious, axillary, solitary, and sessile ; the sterile 

 consisting of a single stamen inclosed in a little membranous spathe ; anther at 

 first nearly sessile, the filament at length elongated. Fertile flowers consisting 

 of a single ovary tapering into a short style ; stigmas 2-4, awl-shaped ; ovule 

 erect, anatropous. Fruit a little seed-like nutlet, inclosed in a loose and sepa- 

 rable membranous epicarp. Embryo straight, the radicular end downward. — 

 Slender branching herbs, growing under water, with opposite and linear leaves, 

 somewhat crowded into whorls, spinulose-toothed, sessile and dilated at base. 

 Flowers very small, solitary, but often clustered with the branch-leaves in the 

 axils; in summer. (Xalds, a water-nymph.) 



1. N. marina L. iStem rather ^totit and often armed with broad prickles ; 

 leaves broadly linear (2 mm. broad), coarsely and sharply toothed, the dilated 

 base eniire ; truit 4— j mm. long; seed very finely lineate, oblong, slightly com- 

 pressed. — Marshes and salt springs of w. N.Y., Mich., and Minn.; Fla.; Utah to 

 Mex. — Teeth of one or more brownish cells upon a many-celled base. (W. I., 

 Eurasia, Austr.) 



Var. gracilis Morong. Internodes long (5-8 cm.) and nearly naked, with 

 only a few teeth above ; leaves very narrow (0.5 mm. wide) with 8-12 teeth 

 on each marsrin, the dilated base also toothed ; fruit smaller. — Canoga marshes, 

 w. N. v.; Fla. 



Var. recurvata Dudley. Stems short, inclined to be dichotomously branched, 

 recurved-spreading ; leaves usually recurved, the teeth prominent, 2-7 on each 

 margin, the dilated base with a projecting tooth each side. — N. Y. ; Utah and Ariz. 



2. N. flexilis (Willd.) Rostk. & Schmidt. Sterns nsually very slender ; leaves 

 very narroidy linear (less than 1 mm. wide), very minutely serrulate, tapering 

 gradually to the seriulate base; fruit 2.5-3 mm. long, narrowly oblong; seeds 

 lance-oval, smooth and shining — Ponds and slow streams, Lab. to B. C s. to 

 S. C. and Mo. — Teeth on the margins of the leaves 1-celled. (Eu.) Var. 

 ROBusTA Morong. Stem stout, few-leaved, sparsely branching, elongated ; leaves 

 flat, strongly ascending, linear-tapering. — Mass. to Mich, and Tex. 



3. N. guadalupensis (Spreng.) Morong. Similar; leaves with 20-45 very 

 minute teeth on each margin ; fruit 2 mm. long ; seeds dull, conspicuously 

 reticulate. (JV. microdon A. Br.) — Pa. to Neb., and southw. (Trop. Am.) 



4. N. gracillima (A. Br.) Magnus. Branches alternate; leaves very nar- 

 rowly linear, nearly capillary, straight, serrate, the rounded lobes of the sheath- 

 ing base spinnlose-ciliate ; fruit linear, impressed-dotted beticeen the numerous 

 ribs. {N. indica, var. A. Br.) — Local, e. Mass. toe. N. Y., N. J., and Pa. ; Mo. 

 — Teeth of 3 cells each. 



JUNCAGINACEAE (Arrow Grass Family) • 



Marsh plants, with terete bladeless leaves. Flowers perfect, spicate or 

 racemose, with herbaceous ^(rarely '^)-lobed perianth. Carpels 3 or 6, more 

 or less united, separating at maturity. Seeds anatropous; embryo straight. 

 Fruit follicular or capsular. 



