NAIADACE^E. 385 



simple. Fruit a little nut or indehiscent capsule. Seed with- 

 out albumen. Water plants, with simple cellular leaves and 

 membranous stipules. Flowers inconspicuous, often in termi- 

 nal spikes. 



1. ZOSTERA. Linn. Grasswrack. 



(From the Greek &><"/{>, a girdle or ribbon, which the leaves sometimes re- 

 semble.) 



Stamens and pistils separated, seated in 2 rows upon one 

 side of a flat spadix. Anthers ovate, sessile. Pistils alterna- 

 ting with the anthers, ovate. Style subulate. Stigmas 2. Utri- 

 cle with 1 seed, bursting irregularly. 



Z. marina Linn. : stem roundish ; leaves entire, somewhat 3-nerved. 



Muddy shores. Mass, and N. Y. to Car. Aug. '4-. Stem terete, flexuous, 

 throwing out roots from the joints. Leaves very long and narrow. Spadix 

 linear, arising from a sheathing portion of the leaf. Flowers green ; pistils and 

 anthers alternate. This plant is used in Europe for packing glass and earthen- 

 ware. Beds are also sometimes made of it. Common Grasswrack. 



2. CAULINIA. Wild. Caulinia. 

 (In honor of F. Cavolini ; a Neapolitan botanist.) 

 Monoecious. Perianth none. STERILE FL. Anther nearly 

 sessile. FERTILE FL. Style filiform. Stigmas 2. Fruit capsu- 

 lar, 1 -seeded. 



1. C. fragilis Willd.: leaves ternate or opposite, linear-subulate, re- 

 curved, aculeate-dentate, rigid. 



In water. Penn. Aug. . Stem long, submerged. Flowers small. 



Brittle Caulinia. 



2. C.flexilis Willd.: leaves whorled in sixes, linear, denticulate near 

 the apex, spreading. Najas Canadensis Mich. 



Ponds and ditches. Can. to Car. July, Aug. .Stem 618 inches long, 

 submerged, dichotomously branched, jointed. Flower solitary, axillary, sessile. 



Bending Caulinia. 



3. ZANNICHELLIA. Linn. Horned Pondweed. 

 (In honor of John Jerome Zannichelli ; a Venetian apothecary and botanist.) 



Monoecious. STERILE FL. Perianth none. Stamen 1. Fila- 

 ment slender. FERTILE FL. Perianth cup-shaped. Pistils 

 2 4, tapering into a short style. Stigma large and peltate. 

 Fruit on a short stipe, coriaceous. 



Z. paluslris Linn. Z. intermedia Torr. Comp. 



Ditches and stagnant waters. Can. to Virg. July, Aug. (T). Stem long, 

 filiform, much branched. Leaves opposite, linear, entire. Flowers axillary, 

 from a membranaceous cup-shaped perianth or involucre, small. Stamen 

 longer than the pistils. Anther large, 4-celled, (Hook.) 2-celled, (Torr.') Stig- 

 ma entire. Fruit a little incurved, sometimes toothed on the back. 



Horn Pondweed. 

 1Y 



