Fes. 1905. ] BOTANICAL SOCIETY OF EDINBURGH. 81 
be shown by injured parts, and by figures of the insects. 
The fungus parasites are not less important, including such 
forms as Plasmodiophora Brassice, Peronospora parasitica, 
Cystopus candidus, and others, and should be similarly 
noticed, as also the connection of both the insects and the 
fungi, with turnips, cabbage, and other cultivated species of 
Brassica, increasing the hurtfulness of charlock as a weed. 
The whin or gorse (Ulex europwus) may be treated from 
most of the points of view mentioned under charlock, but it 
exhibits certain features in addition, such as the marked 
fleshiness of cotyledons, the three-lobed early leaves, the 
adaptations of stems and leaves for defence and for special 
habitats, the influence on structure of a moist atmosphere, 
the woody stems, the symbiotic association with bacteria for 
nutrition in the root-tubercles, th highly specialised flowers 
and mode of pollination, among others less peculiar. 
The inseet-capturing plants, the mycorhiza-symbionts, the 
partial and the complete parasites, and many others, afford 
striking examples of other extremely curious types; but the 
charlock may suffice (as representative of the great majority 
of plants) to show in how many aspects each may and 
should be regarded. 
It may be objected that to commence a herbarium on so 
extensive a plan is to undertake a work impossible of 
completion. Ina sense that is true; and to me it appears 
a very real advantage that the herbarium should be planned 
to expand with each advance of our knowledge in botany, 
and also to give efficient aid in opening up new fields of 
inquiry. So planned, the motive to go on continues un- 
checked, for each step of progress only leads on to others 
not previously within sight. 
I venture to think that such a herbarium as that suggested 
will be found a most valuable instrument in promoting the 
study of diving plants, in its formation no less than in its 
constant usefulness. 
The PRESIDENT gave a communication on Saxifraga Grise- 
bachii and its allies, illustrated by both living and dried 
specimens. 
Mr. R. D. Cote forwarded for exhibition a specimen of 
Taxus baccata from a bog in Ireland. 
TRANS, BOT. SOC. EDIN. VOL. XXIII. 
6 
