BRITISH HAWKWEEDS. 195 
tration starts at the eyes; those nearest the diseased spot decay, and 
thence, mostly without perceptible alteration on the exterior, the 
disease passes inwards an becomes localised in pcm parts of the 
ich are ned the youn 
tubers, singly or often massed together in clusters, have their walls 
suberised, while the surface of the penetrating rp and tubers is 
protected in the same way. This occurs not only where, through 
formation of a a the interior becomes e spopd but right in the 
the former, with its young tubers, woh hoe rise 0 a mebllbel n pro- 
ducing layers of periderm, in the latter we find simply suberi ssc 
may be asked why the adventitious buds at their formation 
should not break out and grow freely in the air, rather than force 
their way through a resistent tissue. But we can understand that, 
dealing as we are here with shoots, which in the natural order of 
ESCRI Rings oF eae 336.—A. An old potato bringing forth young tubers 
origin at the = of an aérial shoot = indicated at x; «/ is near ns ae of 
another shoot. ©. Longitudinal section of the origin of an intraso: 
(a) ah the — of an aérial shoot (0d), at ing the arrangement of ae Lahtle 
BRITISH HAWKWEEDS. 
By Epwarp F. Seite Ach: anp Wm. R. Linton, M.A. 
(Concluded from p. 182.) 
eustales, n.sp. A plant gathered in Glen Derry, 
8. nye 1889, stood alone for some time, the eR ne — too 
sexfty to deal with. No name was even suggested. Dr. berg, 
to whom it was sent, observed on it, “Species pulchra, bene ut 
Perth, viz., on Meall Ghaordie, on the Glen Lyon side, and on 
Meall-na-Saone, 0 n rocky sides of the Allt Dubh Galair, of a plant 
which was pss found to be practically identical with the 
Glen Derry form. The latter, probably from growing on granite, 
0 2 
