TRANSACTIONS OF THE SECTIONS. 115 
BOTANY AND ZOOLOGY, inctupinc PHYSIOLOGY. 
Borany. 
Mr. Barnas, of York, exhibited a bunch of grapes, which presented the peculiarity 
of black and white grapes on the same bunch. 
On the Geological Distribution of Plants in some Districts of Yorkshire. 
By Dr. Carrincron. 
The chief tract taken for illustration was that part of Craven included between 
Gordale and Kingsdale, and cut off on the south by the magnificent line of scars 
known as the Craven fault. The physical and geological peculiarities of the district 
were minutely described. The origin of the present vegetation was referred to dif- 
ferent periods; the more ancient portion, including plants of boreal type, being 
probably a remnant of the Pre-Glacial Flora. The species found in Craven are 600 
flowering plants, and about 500 mosses and lichens. 
After considering the present state of our information as to the geognostic relations 
of plants, the following classification of strata was recommended, each group being 
characterized by a peculiar Flora :—ist, Calcareous formations, highly absorbent, 
acted on by the elements chemically rather than mechanically (the carbonic acid in 
water dissolving the lime), forming adry, scanty, but fertile soil; 2nd, arenaceous 
formations, disintegrating freely, and producing an abundant sandy deposit, on a 
large scale, forming absorbent, barren stations; 3rd, argillaceous formations, sub- 
ject to rapid abrasion, forming clayey deposits, comparatively impermeable and 
hygroscopic. In practice we find these often mingled together, e.g. shales with 
sandstones; and the soils frequently differ in nature from the rocks they cover, 
having been derived from distant sources. The practice of agriculture has especially 
tended to mingle and equalize the soils of various districts. 
The prevailing rock of Craven is the scar limestone. It supports the greenest of 
pasturage, and most of the rare species are found on it, e. g. Acta spicata, Draba 
incana and D. muralis, Cardamine impatiens, Hutchinsia petrea, Hippocrepis comosa, 
Dryas octopetala, Saxifraga oppositifolia, Hieracium Gibsoni, Bartsia alpina, Primula 
farinosa, Epipactis ovalis, Cypripedium calceolus, Lastrea rigida, and many character- 
istic mosses and lichens ; the latter deserving especial notice from growing directly 
on the rocks. The prevailing lichens are species of Collema, such as C. nigrum, 
stygium, fluviatile, &c., Parmelia crassa, P. calcarea, Lecidea lwrida, candida, im- 
mersa, saxatilis, calcarea, &c., Verrucaria immersa, Gagei, Dufourii, plumbea, and 
epipolea. 'The sandstones are restricted to the millstone-grit, capping Ingleborough 
and other summits, upwards of 2000 feet high. They are covered by a coarse brown 
vegetation of ling, heath, crowberry, bilberry, Juncus squarrosus, &c. The lichens 
are brown and golden coloured, e. g. species of Umbilicaria, Parmelia atra, olivacea, 
saxicola, badia, murorum, Lecidea lapicida, confluens, prominula, fusco-atra, and 
rupestris. The argillaceous rocks are represented by the Yoredale shales and Lower 
Silurian slates, exposed in Ribblesdale and Chapeldale. They afford damp, dripping 
stations, supporting a scanty glaucous vegetation of Equiseta, rushes, and Carices, 
e. g. Sedum Rhodiola and 8. Telephium, Saxifraga aizoides, Carduus heterophyllus, 
Equisetum hyemale and variegatum, Allosorus crispus, Hymenophyllum Wilsoni, Sco- 
lopendrum ramosum, &c. Lichens: Parmelia conspersa, P. sulphurea, Sticta herbacea, 
sylvatica, scrobiculata, Nephroma, Lecidea confervoides, yeoyraphica, polytropa, rivu- 
losa, and many others. 
Dr, Heaton exhibited to the Section a specimen of a plant, which bore on the 
same branches the characteristic leaves of two distinct species of Cytisus. 
Researches on the Colours of Leaves and Petals. 
By W. E. C. Nourse, F.R.C.S. 
In a paper published by the author in the ‘ Annals of Natural History’ for 1845, 
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