386 BAKER’S NORTH YORKSHIRE. 
especially amongst the hills, ascending to the plateau of 
Cronkley Fell. 
Potamogeton plantagineus Ducr. English . type. 
Native. Area 8.4. Range o-150. Pond by the side of the 
railway between Sinderby and Melmerby ; Hebblethwaite! Bogs 
near the Black Beck in Baysdale ; W. Mudd! 
Zostera marina L. British type. Native. Maritime. 
Area 5. Range Coast-Level. In several places upon the shore 
of the Tees estuary. 
Ruppia maritima L. British type. Native. Maritime. 
Area 5. Range Coast-Level. Abundant in some of the salt- 
water ditches in Coatham marshes. Our plant is the true 
maritima. 
Zannichellia palustris L. British type. Native. Area 
S 607 3.2.1. Kange 0150: Frequent in ponds and ditches 
in the low country. Our inland plant is the Zannichellia repens 
Bonng., and Zannichellia pedicellata Fries grows in the salt-water 
ditches at Middlesbrotgh and Coatham. 
Lemna minor L. British type. Native. Area general. 
Range 0-300. Common in ponds and ditches throughout the 
lower zone. 
Lemna gibba L. English type. Native. Area 6. 1. 
Range o-100. In the Central Valley in Sheriff Hutton Carr and 
in the lower part of the Foss. Askham Bogs ; A. Lbbotson. 
Lemna polyrhiza L. English type. Native. Area 6. 3 
21. Range o-roo. Ponds and slow streams in the low 
country, rare. Askham Bogs. Newsham Carr, Raskelf, 
Sheriff Hutton Carr, Flaxton, Stockton Forest, Castle Howard, 
and in the lower part of the Foss. 
Lemna trisulca I. English type. Native. Area 8- 
65.321. Range oroo. Not unfrequent in ponds and ditches 
in the low country. Kirkby Wiske, Hob Moor brick-ponds, Ask- 
ham Bogs, Long Marston, Stokesley, Great Ayton, Coatham 
marshes, Thirsk, Bagby, Topcliffe, Crambeck, Scarborough, etc. 
pae 
