HAIADACEf. S68 ZANNICHELLIA. 



1. ZOSTE'RA. 



Spadix linear, bearing Ihe separated flowers in 2 rows on 

 one side; perianth 0. Sterile Jl. — Anther ovoid, sessile, par- 

 allel to the ovary. Fertile Jl. — Ovaries 2, ovoid ; style bifid ; 

 utricle 1 -seeded. 



Gr. ^uc-rtiS^, a girdle ; alluding to its ribbon-like leaves. 

 Z. mari'na. 



S^ew trailing, throwing out tufts of fibrous roots at the joints; hranchts 

 floating, simple ; tcaves alternate, linear, entire, sheathing at base, 1 — several 

 feet in length; receptacle or spadix linear, flat, pale green, 2 inches long, 

 issuing from a cleft in the base of the leaf, covered in front with a double 

 series of naked flowers. Habits aquatic, growing in the sea on sandy banks 

 and shallows, and is thence washed upon the shore by tlie waves. Like other 

 sea-weeds, it is gathered for manure. Aug. Per. Sea Wrack- grass. Eel-grass. 



2. NAJAS. 



Flowers often dioecious. Sterile. — Calyx cylindric, 2-cleft; 



stanaen 1 (rarely more) ; filament slender, often elongated; 



anther 4-valved, valves spreading. Fertile. — Perianlli 0; 



style filiform; stigma 2 — 3-fid ; capsule 1-sceded. 



Gr. vu(o, to flow ; hence Nats, or NaiSf«, Nymphs of the waters, after 

 whom these little plants, for their habit, were named. Fls. axillary. 



N. CaNADE'NSIS. L. Cauliniaflexilis. /FiW. Fluialis flexilis. Per5. 



Stems fiUform, caespitose, dicholomously branching; leaves opposite or 

 fasciculate in 3s, 4s or 6s, at the nodes, linear, obscurely denticulate, spread- 

 ing, l-nerved. A slender, flexible, rather erect, submersed aquatic, consisting 

 of tufts of thread-like, knotted stems, G — \2 inches long. Leaves i — 1 inch 

 long, ^ line wide, ses.'sile and sheathing at base. Flowers solitary, sessile, 

 axillary, very small, the fertile ones consisting of an oblong ovary tipped 

 with a filiform style, with 2 — 3 stigmas at summit. In stagnant waters. 

 August. Water Nymph. 



/3. (Caulinia fragilis. Willd.) ; stems and lca7:is rather rigid, the latter mostly 

 opposite and recurved. 



3. ZANNICHE'LLIA. 



Flowers monoecious. Sterile. — Stamen 1 ; filament elon- 

 gated. Fertile. — Calyx monophyllous ; corolla 0; ovaries 4 

 or more, each with a single style and stigma, and becoming in 

 fruit an oblong, incurved, subsessile achenium. 



In honor of Zannichelli, an eminent botanist of Venice. 



Z. PALU'STRIS. 



Sterns filiform, floating ; /rrrrrs opposite, linear ; fl7?///c7-s 4-celled ; stigmas 

 entire ; aclienia tootlied on tlie back. In pools and ditclies. Stem round, 

 smooth, 1 — 2 feet long, branching, leafy. Leaves grass-like, 2 — 3 inches long, 

 sessile. Flowers issuing from axillary brads, small, 2 together, a sterile and 

 fertile, the former consisting of a single, naked, erect, yellowish brown stamen, 

 the latter of 4 — 6 ovaries which are free from the inflated, one-sided, 

 2 — 3-toothed calyx. July, Aug. 



