NATADACE^;. 51 



inucronntns. Sometimes, however, the two nrc extremely dillieult 

 to distiiiu'uisli in the dried state wlieii not in flower or Iruit, and they 

 arc probably distinct only as subspecies. 



. Small Pondweed. 



French, Potamot fluet. German, Kleines Samkraut. 



SPECIES XXI.-POTAMOGETON TRICHOIDES. Cham. 



Plate MCCCCXX. 



Ifdch. Ic. n. Germ, et Helv. Vol. VII. Tab. XXI. Fig. 34, and Tab. XXII. Fig. 35. 



IlUlot, Fl. Gall, et Germ. Exsicc. No. 654. 



P. monogynus. Gay in Coss. & Germ. Fl. Par. ed. i. p. 572. 



P. tuberculatum, " Ten. & Guss. in Act. Soc. Borb. Vol. V. p. 430" (^Coxs.). 



Stem subcylindrical, not compressed, filiform, repeatedly diehoto- 

 mous or trichotomous. Leaves all similai", sessile and semi-amplexicaul, 

 linear-seta'ceous, not narrowed towards the base, acute, with only 1 

 longidinal rib ; many of the leaves with 1 or 2 branches in their 

 axils. Stipules small, subacute, subscarious, with numerous slender 

 longitudinal fibres. Peduncles terminal from the forks of the stem, 

 much longer thann the spike (usually 6 or 8 times as long), filiform, 

 not thickened upwards. Sepals with their lamina suborbicular. 

 Pistil solitary. Fruiting-spike oblong-ovoid or subglobose, usually 

 slightly interrupted, very few-flowered. Fruit rather small, greenish- 

 olive, slightly compressed, not acuminated, nearly straight along the 

 upper margin, where there is a prominent tooth near the base, semi- 

 circular and bluntly keeled on the back, terminated by a very short 

 straight beak forming a continuation of the upper margin ; keel nearly 

 entire, subdenticulate or tuberculate. Plant deep dull green, becoming 

 much darker when dried. 



In ponds, ditches, and slow water, in muddy soils. Discovered by 

 the Rev. Kii-by Trimmer at Framingham Earl, Norfolk : the following 

 other stations are given in that gentleman's " Flora of Norfolk " : — 

 " Swardiston. Swanesthorpe. Alpington. Marlingford. Lyng. 

 Alburgh. PuUiam. St. ]\Iary the Virgin. In a slow water ditch near 

 the railway station, Tivetshall. Walpole St. Peter (Mr. Lowe)." 



England. Perennial. Summer. 



Very similar in habit to P. pusdlus, var. tenuissimus, but more 

 copiously branched, with the branches divaricate. The leaves narrower, 

 more slender and rigid, rarely above 1 to 1 J^ inch long: the peduncles 

 are much longer, frequently 2 inches lone:: the flowers are fewer, and 

 appear to have always only one pistil : the fruit is about j'j, inch long 



•an TJi JO '0 



