36 THE DISTRIBUTION OF EAST RIDING PLANTS. 



having the fleshiness of this class, e.g. Cochlearia officinalis, 

 Cerastium tetrandrum, an almost fleshy form of Anthyllis 

 vulneraria, and Matricaria maritima. 



The plants of (c), the sandy parts of the coast, form a 

 very distinct association, nearly all the members of vv^hich 

 show a characteristic succulency and a glaucous external 

 colouring. Take for example Crambe maritima, Cakile 

 maritima, Silene maritima, Hockyenia peploides, Eryngium 

 maritimum, Statice Limonium, Convolvulus (Volvulus) 

 Soldanella, Beta maritima, Atriplex litoralis, Salsola Kali, 

 Hippophae rhamnoides, Carex arenaria, Phleum arenarium, 

 Ammophila arundinacea, Triticum junceum, and Elymus 

 arenarius. The last three grasses, together with Hippophae, 

 sea buckthorn (the "dune-thorn" of the Dutch), are the 

 principal agents in binding together the sands of the 

 somewhat precarious spit of land forming Spurn peninsula 

 and headland. 



II. The Northern Bank of the Humber, whose 



tidal waters wash all three of the main physical divisions 

 from Goole to Spurn, bears another very well marked group 

 of plants. These are such as are usually found near an 

 estuary, and many of them are also of undoubted halophytic 

 tendency. Although they frequently bear the specific name, 

 "maritima," they are scarcely seaside plants with us; 

 indeed we rarely find any of them except along the estuary. 

 Of the estuarine association are Buda (Spergularia) marina 

 and B. media, Trifolium fragiferum, Bupleurum tenuissimum, 

 Apium graveolens (Celery, an exceedingly common estuarine 

 plant), Aster Tripolium, Artemisia maritima, Armeria 

 maritima, Glaux maritima, Atriplex Babingtonii, A. portu- 

 lacoides, Suaeda maritima, Rumex maritimus, Triglochin 

 maritimum, Ruppia spiralis, Juncus Gerardi, Scirpus 

 maritimus, Carex divisa, C. extensa, Glyceria maritima, 

 G. distans, Lepturus filiformis, and Hordeum marinum. 



III. Of Holderness and Derwentland we have next 



to consider the vegetation found in watery places, and as 

 these vary from. the stagnant to the flowing condition, and 

 also according to the subjacent rock, it is quite possible to 

 make out several very distinct associations. The habitats 

 we classify as under : — 



(«) Rivers, streams, larger drains and canals. 



[b) Dykes (narrow, sluggish, or stagnant open drains), 

 ponds, and meres (lakes). 



