194 HULL SCIENTIFIC AND FIELD NATURALISTS CLUB. 



surface of ponds and dykes in spring and early summer. 

 On the edges of the drains grow the great meadow rue 

 (Thalictrum flavum), mingling with the greatest dock (Rumex 

 hydrolapathum) the yellow iris and the largest of the sedge 

 family. On the water float the yellow, and occasionally also 

 the white water lily, whilst arrowhead, the rose-tinted 

 flowering-rush, handsomest plant in Holderness, rise above 

 the water level. The colour scheme of the marshy and 

 watery places is exceedingly fine ; add to the above- 

 mentioned masses of purple loosestrife {Lythrum), water 

 violet, bogbean, water forget-me-not, the orchids — latifolia, 

 incarnata and Epipactis palustris, and an idea of the gaiety 

 of the solitary place may be obtained. In one marshy spot 

 near the River Hull, the rambling lover of wild plants in 

 early July would have his vision cheered by the sight of 

 plant quintette of rare occurrence elsewhere. These are the 

 marsh pea (Lathyrus palustris) which is not now known in 

 any other Yorkshire situation, the great yellow loose-strife 

 (Lysiwachia vulgaris), the rare sedge (Carcx paradoxa), the fast 

 vanishing marsh buckler-fern (Lastraa Thelypteris), and waving 

 over all, the purple and silvery plumes of the small-reed 

 (Calamagrostis lanceolata). 



How completely dependent plants are on the special 

 geological and geographical conditions is clearly shown by 

 the quite different association of plants of the aquatic sort 

 that are found in damp places on the sandy tract called the 

 " Levels " (Derwentland). Here, and here only, the marsh 

 St. John's wort (Hypericum elodes), and the beautiful blue 

 gentian or " Calathian Violet" (Gentiana Pneumonanthe), 

 mudwort (Limosella), and pillwort, Pilularia, all grow in 

 profusion. This also is our best district for the plants who 

 make part of their food of insects for the capture of which 

 they are specially adapted. Such are the two sundews, the 

 butterwort and bladderwort ; whilst the chastely beautiful 

 "Grass Parnassus" with its large white flowers, so con- 

 spicuous in many a marshy place in early autumn, is a not 

 remote relative. 



Before leaving the sandy tract it may be observed that 

 it is the only part of the East Riding where heather and 

 the cross-leaved heath grow in abundance, and the rose bay 

 willow herb and many varieties of bramble and fern still 

 luxuriate. One plant of the orchidaceous type, Goodyera repens, 

 is found growing in a Scotch-fir wood on Houghton Moor, the 

 only place in England south of Northumberland. 



Of the fields and woods of the lower positions of the 



