Yorkshire Naturalists at Thornton Dale, 291 
fine example of the ‘ Vaccinium edge ’ described by Moss. Here occur 
Cornus suecica and Trientalis europea. 
A marked contrast to the oak woods was offered when the vegetation 
of the valley bottom was examined. An interesting alder wood ( A , 
microcarpa ) on alluvium just above the ‘ fish pond ’ seem to illustrate 
the primitive vegetation of these bottoms. Carex acutiformis, Spima, 
Caltha and J uncus sylvaticus were the most abundant species of the 
ground flora. Two possible lines of development seemed possible for 
this wood. Where the soil level is being raised by further silting, ash 
is frequent, and will probably finally become the dominant tree. Where 
the soil level is being raised by accumulation of organic matter, soil 
acidity is developing, with a transitional vegetation of Sphagnum, 
Molinia, Calluna and Erica tetralix. In several places, the influence of 
calcareous flush waters is shewn. These limey flushes are best seen on 
the eastern slopes of the valley. They produce a ‘ marly ’ soil (20-50% 
r of calcium carbonate) bearing a vegetation of Schoenus nigricans, Hypnum 
commutatum, Blysmus compressus, Eleocharis multicaulis , Carex dioica, 
Selaginella, etc. Associated with these, but apparently rooting in the 
humus above the marl, are heath species like Nardus, Molinia, Calluna, 
Dicranum scoparium and D. Borjeani. A curious feature of these flushes 
was the absence of all but the commonest mosses ; on the other hand 
±he alga Spirogyra variabilis was exceptionally plentiful. 
Flowering Plants (A. I. Burnley). — On Saturday morning the 
party explored the western side of the Ellerburn Valley. In the coralline 
oolite quarries the burnet rose was found in bloom. The members next 
investigated the beech wood close by, and saw the fly and greater butterfly 
orchids in plenty. This year the bird’s nest orchid was scarce. Near at 
hand, the sweet and hairy violets, and a hybrid between the two, were 
common. Cleistogamous flowers of the violets were plentiful. In the 
part of the wood nearer Ellerburn, where the beech is almost entirely 
replaced by poor ash, columbine, hairy Saint John’s wort, and plough- 
man’s spikenard were noted. On an open, dry limestone slope, the 
common rock rose and lesser burnet were common, as might be expected, 
and the pill-headed sedge was also there. 
At Ellerburn a large patch of monkshood (probably an escape) had 
found a habitat suitable to its liking by the stream side, and near at 
hand the common barberry was examined for the fungus causing ‘ rust ’ 
on wheat, but with no result. 
The most interesting feature of the day was the examination of the 
dry, treeless slopes west of Dalby Warren. The occurrence of wood 
anemone, fly orchid, ploughman’s spikenard, stone bramble, shade-loving 
ferns, etc., shows that probably a wood formerly occupied this locality, 
but not within the memory of Mr. J. Green, the keeper. White bryony 
was trailing about, and viper’s bugloss seems to be a recent invader. 
Dalby Wood was next visited for lilies-of-the valley, herb paris, 
spindle-tree columbine and baneberry. The place was remarkably rich 
in the two last-named plants, and it is unfortunate that the wood is being 
■cut down. 
A small party tramped to Crosscliff on Whit Sunday. On the way up 
the valley, the green -winged orchis and the dwarf orchis were growing 
in a meadow with the greater burnet not far away. The locality for the 
dwarf orchis ( Orchis ustulata) was by no means typical. 
At Crosscliff, at the upper edge of the escarpment, dwarf cornel, 
chickweed, winter-green, common cow-wheat, ling, crowberry, cowberry 
and bilberry seemed to be struggling for space above the wood clothing 
the scarp. The blooms of the cornel were less common than usual. The 
writer has found cornel on Blakey Topping. At the Hole of Horcum the 
cornel was seen at a considerable distance down the slope, and 
on the adjoining moor top specimens of the dwarf tway -blade were 
gathered . 
1922 Aug.-Sept. 
