506 NAJADEiE. 



CXXVI. HYDEOCHAEIDEJ;. 



Flowers corolkte, unisexual or polygamous. Ovary inferior : style divided. Seeds ex- 

 albuminous. Embryo straight : radicle large.— Aquatic, floating, or submersed herbs ; pe- 

 duncles supported by spathaceous bracts. 



1. LIMNOBIUM, Rich. 



Flowers unisexual. Sepals 3. Petals 3. Anthers 6-12, linear, inserted into a short 

 column. Ovary 6-9-celled: ovules " atropous ;" stigmas 3-partite. Berry many-seeded. 

 — Stoloniferous herbs ; leaves rosular, floating ; flowers small, whitish. 



1. Ii. stoloniferum, Or. Leaves oval-oblong or oval-roundish, subacute or roundish 

 at both ends, spongious beneath. — Hydromystria, Mey. Esseg. ! L. Spongia, Steud. ex 

 parte. — L. Bosci, Kich. [Hydroch. t. 8) is distinguished by much larger, subcordate-reni- 

 form leaves : our specimens are in fruit and admit of no further comparison with this species, 

 nor with the monoecious L. Sinclairii, Benth. Leaves 6"'-12"' long, 4"'-8"' broad.— Hab. 

 Trinidad !, Cr. ; [Guiana !]. 



CXXYII. NAJADE^. 



Flowers apetalous or nidced. Ovaries free, distinct, or solitary, 1-ovulate. Seeds ex- 

 albumin'ous : radicle mostly large. — Aquatic, floating, or submersed herbs ; spadix {or flower) 

 enclosed by or bursting from a spalhe. 



1. POTAMOGETON, L. 



Flowers spicate, hermaphrodite. Sepals 4 : anthers inserted into their claw. Ovaries 4, 

 becoming slightly succulent achenia. Embryo curved. — Leaves alternate (or opposite), 

 stipulate ; i-paia. peduncled, emersed. 

 ^y^ 1. P. fluitans, Rih. Stem cylindrical, proliferous; leaves chartaceoits, all long- 

 petioled, uppermost floating, oblong or lanceolate-oblong, tapering at the base: petiole 

 convex above : submersed ones persistent, narrower, alternate : stipules free, not keeled ; 

 spikes cylindrical : peduncles equally big ; carpids keeled. — Cham, in Linnaa, 2. t. 6./. 24 : 

 the fruit. — P. oecidentalis, Sieb. Mart. 275 ! — Hab. Jamaica!, March; Trinidad!, Or., in 

 rivers ; [Cuba ! to Martinique ! ; both temperate and tropical zones of the globe]. 



2. P. plantaginea, i)«(;r. Tar.^'aiK«we««V. Stem cylindrical, branched ; leaves mem- 

 branaceous, shortly petioled, lanceolate-oblong or uppermost oval, even at the margin : 

 stipules free, keeled; spikes cylindrical: peduncles equally big; carpids shaarply heeled. — 

 !Prom the European form this variety is only, distinguished by shorter petioles, and the 

 leaves narrower, all or the inferior long-tanraing at the base : from the, allied, often very 

 similar species, it is more distant, viz. fronTP. lucens, L. by the carpids half as large and 

 sharply keeled, by equal pedun«les, by the transverse veinlets of the leaves rarely divided 

 and the leaf-margin even, from P. preelongv.s, "Wulf. by the petioles, and from the large- 

 leaved forms of P. heterophiyllus, Schreb. (P. Zip.i, Kch.) by the carpids and the even 

 leaf-margin. — Hab. Jamaica !, ,/iA, Wils.: a form with all leaves submersed ; [o: western 

 and southern Europe 1]. 



2. ETJPPIA, L. 



Flowers nalced, hermaphrodite. Stamens 2 : anther-cells 2, distinct. Ovaries 4 (3-6), 



at length stalked by a long carpophore. Embryo " ovoid." — Stem submersed, filiform, 



branched ; leaves capillary, sheathing at the base ; flowers 2 or several near the summit 



of axillary peduncles. 



y 3. B. maritima, L. Anther-cells ovoid-oblong; carpids obliquely ovoid, shortly 



