316 POTAMOGBTQNACE^. [Zanichellia. 



This is by far the more common form ; it is reported from 

 Cork, Dublin, and Belfast. The only specimen which we 

 have seen of the typical R. maritima is one preserved in the 

 Herbarium of the late Dr. Mackay, and labelled " near 

 Dublin, &c." 



ZANNICHELLIA Linn. 

 1. Z. palustris (Linn.) — Horned Pond-weed. 

 Districts 12-45-789 10- 12 

 Lat. 51°-56°. Throughout Ireland. 

 Type in Great Britain, British. 



Kivers, ditches, and pools ; frequent. Fl. June to August. 

 Chiefly in brackish ditches near the coast, but occurs also 

 in fresh-water not unfrequently. 



ZOSTERA Linn. 

 1. Z. marina (Linn.) — Common Grass-wrack, 

 Districts 12. -456-89- 11 12 

 Lat. 51°-56°. Coasts of all Ireland. 

 Type in Great Britain, British. 



Muddy estuaries and shallow sea-shores; common. Fl. 

 July, August. 



Very variable in size and in the breadth of the leaves. 



2. 2. nana (Roth) — Dwarf Grass-wrack. 

 District ____5--. — ---- 

 Lat. 53°-54°. East coast of Ireland. 

 Type in Great Britain, English. 



Muddy estuaries ; very rare. Fl. July to September. 



5. On mud in the creek close to the railway station at 

 Baldoyle, Dublin ; A. G. M. The transverse bands of the 

 spadix were well seen in the few specimens gathered. It 

 appears to flower very sparingly, and grows in company with 

 Z, marina, var. angustifolia. 



