130 THE SAND STKAND FLOKA 



P. pectinatus L. 



Perennial marine plant, with threadlil\e stem, very narrow leaves, 

 5 — 8 cm. long, sheathing at base. 



On sulDmerged beaches of Europe and Xorth America. In some 

 cases in inland waters of the latter continent. 



Ruppia maritima L. 



Submerged aquatic herb, with 6 — 10 dm. long, filiform forking stems; 

 leaves 5 — 8 em. long, almost capillar}', with a broad sheathing base. 



In salt and brackish water over nearl}' the whole globe, excepting 

 South America. Also in the interior of North America. 



Verjr variable and divided into several species. 



Triglochin maritimum L. 



Perennial, with short rootstock, the terminal portion of which is 

 covered with the sheaths of old leaves; stem 15 — 45 cm. high; leaves 

 about 5 mm. -wide, fleshy with membranous sheaths. 



Coasts of Europe, Asia, and North America. Also in interior of 

 latter continent in saline situations. On Pacific coast from San Fran- 

 cisco northward to Arctic Ocean. 



T. striatum Euiz. & Pavon. 

 Eootstock small, stolonif erous ; leaves narrow-linear, shorter than the 

 scape; fruits nearly orbicular. 



Brackish water in North America, extratropical South America, New 

 Zealand, Tasmania, and Australia from Moreton Bay along south coast 

 to Fremantle. 



Zanichellia palustris L. 

 Inconspicuous submerged aquatic, with capillary stems and leaves; 

 these alternate or mostly opposite, 1 — 3 cm. long. 



"Widely spread over the whole globe. Often in ponds between dunes. 



Zoetera marina L. 

 Submerged maritime jDerennial, with elongated and very narrow 

 grass-like leaves, with sheathing bases, 3 — 7-nerved, 3 — 10 dm. long, 

 3 — 13 mm. broad, obtuse. 



In shallow water on submerged beach, especially on mud, on coasts 

 of Europe, North Eastern Asia, Arctic and North Atlantic coast of 

 North America, and on the Pacific coast at least as far south as San 

 Pedro, California (Dudley). 



