TETKANDBI A TETR AG YNI A. 4 1 



according to Dr CHANDLER, " houses were decked with 

 them, that the sylvan spirits might repair to them unnip- 

 ped by frost and cold winds, until a milder season had re- 

 newed the foliage of their darling abodes." 



53, POTAMOGETON. 



1. P. natans, upper leaves oblong-ovate, stalked, floating, co- 

 riaceous; lower ones linear, membranous, sessile. Broad-leaved 

 Pond-weed. 



Hab. Ponds and rivulets, common. July. If. 



2. P. perfoliatum, leaves heart-shaped, clasping the stem, uni- 

 form, all submersed. Perfoliate Pond-weed. ; - 



Hab. Tn the Tweed and Whiteadder, and in large ponds, 

 common. July. 11 



3. P. heterophyllum, upper leaves elliptical, stalked, floating, 

 slightly coriaceous ; lower ones lanceolate, membranous, sessile ; 

 flower-stalks swelling upward. Various-leaved Pond-weed. 



Hab. Coldingham Lough. July-Sept. If. 



Our specimens were imperfect, but the species was deter- 

 mined by Mr WINCH. The stems are long, slender, 

 round, sparingly and distantly branched. Lower leaves 

 alternate, distant, pointed, with spinous serrated edges. 

 They are beautifully ribbed, the ribs being connected by 

 regular parallel side-branches. 



4. P. lucens, leaves elliptic-lanceolate, very large, pointed, 

 membranous, stalked, repeatedly triple-ribbed, all submersed ; 

 spike dense, many.flowered. Shining Pond-weed. 



Hab. In the Tweed, above the Union Bridge, plentiful. 

 June, July, % 



5. P. crispum, leaves lanceolate, waved, serrated, alternate, the 

 upper ones opposite ; flowers in loose spikes. Curled Pond-weed. 



Hab. Ponds, common. J uly. If. 



6. P. pusillum, leaves linear, pointed, opposite or alternate, 

 3-ribbed ; stem compressed on one side ; flower- stalks axillary, 

 mostly lateral, many times longer than their spikes. Small Pond- 

 weed'. 



Hab. Ponds and slow streams, frequent. In the Tweed 

 and Whiteadder. Loch in Holy Island, and at Colding- 

 ham. July. If. 



