EXHIBITION AND LECTURE MEETINGS, 1951 
59 
SESLEBIA IN N.W. Europe. 
Living plants were exhibited of the grass Sesleria, which consists of 
two distinct species in Europe (cf. Love, A., 1950, Bot. Notisei , 
1950 , 27-30). The true S. caerulea (L.) Ard. (which can be distin- 
guished readily by the easily-removed waxy covering to the upper leaf 
surface) is Scandinavian and E. European; our plant, which occuis 
also in Iceland and W. and C. Europe, is S. varia (Jacq.) Wettst. The 
two species differ remarkably in the appearance of the upper leaf epidei- 
mis, including the stomata; a slide of this w'as exhibited. 
S. M. Walters. 
IiITTLF.HKNOWN HaWKWEEDS 
The following eight species of Hawkweeds wmre exhibited: II 
macrocarpum, Pugsl., B. pseudo-repandum Pugsl., II. fratrum Pugsl., 
77. oxyodus W. R. Lint., 77. pollinarioides Pugsl., H. caliginosum 
(Dahlst.) Roffey, 77. dipteroides Dahlst. and 77. suhquercetorum Pugsl. 
They have the following four points in common: — all except B. caU- 
ginosum (Dahlst.) Roffey, are endemic; they are all confined to a re- 
stricted area; they are clearly separable from their allies; they were 
known only from the original collections until rediscovered in the past 
two years by O. D. Pigott, J. E. Raven, and C. West. All the above- 
mentioned species were found growing in their classic localities as cited 
by H. W. Pugsley in his ProdromAis of the British Bieracin, although 
sometimes sparingly. 77. suhquercetorum Pugsl. was found in an ad- 
ditional locality near York by Prof. C. E. Raven. 
P. D. Sell. 
rOA ANNUA L. AND BEBAGLEUM SPBONBYLIUM 
Live plants of an artificial hybrid between P. annua L. 9 and P. 
infirma. H.B.K. S were shown, together with a photograph showing the 
behaviour of the chromosomes of the hybrid at meiosis. 
Specimens of subspecies of Beracleum Bphondylivm L. were exhibited. 
T. G. Tutin. 
Some interesting British Grasses 
The exhibit included sheets and detailed illustrations of two British 
grasses, Phleum commutatum Gaud, and Sesleria varia (Jacq.) Wettst., 
and two related species, P. alpinum L. and S. caerulea (L.) Ard. emend. 
Wettst., with which they have been confused by earlier authors. The 
differences between the above-mentioned species of Phleum have been 
pointed out by Tutin (Watsonia, 1 (4), 226-7), and those of Sesleria by 
Walters (see above). In addition a specimen of an American species 
of Vulpia (V . megalura (Nutt.) Rydb.), recently collected by Mrs. B. 
Welch in W. Kent (Hoo), was shown (for a record from W. Norfolk see 
B.E.C. 191,6-1,7 Bep., 13 , 375: 1948). 
A. Melderis. 
