514 



naiadacf.te 



combined carpels.^Salt marshes ; common.— Fl. Ma) Septem- 

 ber. Perennial. 



2. ScHEUCHZKRiA, represented by the" one species S. palustris, 

 has a long, creeping rhi-zonie ; leaves linear, semicylindric, with 

 swollen brown sheaths ; fivwers 4—6, in a loose, bracteate raceme, 

 perfect ; perianth of 6 similar, reflexed, green leaves ; stamens 6 ; 

 carpAs 3, united below.— Peaty bogs ; -very rare, found only in 

 the north. (Name from the Swiss naturalists, the Scheuchzers;. — 

 Fl. July. Perennial. 



3. PoTAMOGETON (Pond-weed).— Floating or submerged plants, 

 with translucent or opaque, leathery leaves, scattered or opposite, 

 generally stipulate ; flowers in a spike, perfect : perianth of 4 

 small, green, valvate, persistent leaves '; stamens 4 ; carpels 4, 



-tS^ Ss 



POTAMOGiiTOM nAt.\ns {Float'tft^ Pond-ivcid). 



sessile, free, i-seeded. (Name from the Greek pbtamos, a river, 

 and geitOH, a neighbour.) 



* Leaves scattered, or the upper opposite, oblongs ohovate or 

 lanceolate, involute ; stipules free 



1. P. ndtans (Floating Pond-weed). — An aquatic plant, with 

 cord-like stems, proportioned to the depth of the water in which 

 it grows ; upper leaves floating, on long stalks, smooth, leathery, 

 elliptical to lanceolate, 2—6 in. long, with small auricles and very 

 long, pointed stipules, lojoer not ahyays present, submersed, 

 reduced to very narrow linear phyllodes a foot long ; floicers 

 numerous, small, green, in dense cylindric spikes which rise 

 above the surface of the water on stout, axillary peJuncles ; carpels 

 rather large, keeled, with a short b^ak. — Ponds and ditches ; 

 common. — Fl. June — September. Perennial. 



2. P. polyu,onijolius. — A more membranous plant with long- 



