430 NAIAD ACE &. [Triglochin 



1. T. palus'tre, L. ; leaves filiform ^-terete throughout, fruit clavate, 

 carpels 3 slender long attached to the axis by a point. 



Marshes and wet meadows, N. to Shetland ; ascends to 2,000 ft. in the High- 

 lands; Ireland; Channel Islands; fl. June- Aug. — Stem swollen at the base, 

 stoloniferous. Leaves 2-12 in., flaccid, upper surface faintly grooved. Scape 

 slender. Raceme elongating after flowering, pedicels short. Perianth purple- 

 edged. A nthers purple. Fruit appressed to the s ?ape. Carpels terete at 

 the back, narrowed below, axis 3-quetrous. — Distrib. Europe (Arctic) 

 (excl. Greece), N. Africa, N. Asia, N.W. Iadia, N. America. 



2. T. marit'imum, L. ; stems tufted thickened at the base, leaves 

 slightly flattened at the tip, fruit oblong of 6 separable carpels. 



Salt marshes, N. to Shetland ; Ireland ; Channel Islands ; fl. May-Sept. — Larger 

 and stouter tban T.palus'tre; scape curved; raceme longer, not dense-fld., 

 nor so long in fruit ; flowers larger ; fruit not appressed to the scape, and 

 carpels grooved at the back. — Distrib. Coasts of Europe (Arctic) (excl. 

 Greece, Turkey), N. Africa, salt districts of Asia, N. America. 



2. SCHEUCHZE'RIA, L. 



A small marsh herb. Rootstock creeping. Leaves erect, slender. Scape 

 leafy ; flowers racemose, bracteate. Perianth-segments 6, herbaceous, re- 

 flexed, connate at the base, persistent. Stamens 6, hypogynous, filaments 

 short ; anthers long, narrow, adnate to the filament, extrorse. Ovary of 3 

 carpels connate at the base, stigma sessile ; ovules 2-3 in each carpel, basi- 

 lar, anatropous. Fruit of 2-3 inflated spreading follicles. Seeds 1-2, erect, 

 ovoid, testa coriaceous. — Distrib. N. and Mid. Europe (Arctic), N. Asia, 

 Rocky Mts. — Etym. Two Scheuchzers, Swiss botanists. 



S. palus'tris, L. ; leaves ^-terete, sheaths turgid. 



Marshes, rare, Salop, Notts, Chester, York, Perth; fl. July.— Rootstock long, 

 slender, clothed with old leaf-sheaths. Leaves 6-10 in., with dilated brown 

 sheaths and a pore at the tip. Scape stout, curved. Raceme lax, few-fid. ; 

 pedicels much lengthened in fruit. Perianth-segments linear-oblong. Ripe 

 carpels large for the plant. 



3. POTAMOGE'TON, L. 



Aquatic herbs. Leaves submerged and translucent, or floating and 

 opaque, alternate or opposite ; stipules connate, membranous or 0. 

 Flowers 2-sexual, in axillary or terminal spikes, proterogynous. Perianth- 

 segments 4, small, herbaceous, clawed, persistent, valvate in bud. Stamens 

 4 ; anthers subsessile on the claw, 2-celled, extrorse. Carpels 4 (rarely 1) 

 free, sessile, stigma subsessile ; ovules solitary, ascending, campylotropous. 

 Drupelets 4 (rarely 1), small, green. Seed curved round a lateral process 

 from the cell, testa membranous ; radicular end of embryo inferior, large, 

 cotyledonary narrowed hooked or involute, plumule immersed. — Distrib. 

 Temp, regions, more rare in trop. ; species about 50. — Etym. irora^ios, a 

 river, and yelroDv, a neighbour. 



