EXlliniTlON MEETING, 19o2 
IjIMON lU M Ili’MU.E AND THE Amekican Element in the British 
Flora 
The close relationship of L. humile Mill, with the nortli-east North 
American species (especially L. na^hii var. trichogonuin Blake) rather 
than with the European L. vulgure IMill. was illustrated by herbarium 
specimens. Maps showed that L. humile culminates a morphological and 
cytological series from Europe to the Ami'i’icas and back. Unlike all 
other Eurasian species of the subsection Genuinae, but like the North 
American species, L. humile is monomorphic (A / papillate) and self- 
compatible. Self-compatibility is of advantage to a species in establish- 
ment after an isolated disseminule has overcome the hazards of long- 
distance dispersal. 
Thus the evidence is that L. humile arrived in Europe relatively late 
in the history of this subsection. It is most common around Irish shores 
but is also found in England, south-western Scotland and Wales, occur- 
ring otherwise only around the mouth of tlie Baltic and in the north- 
western tip of France. The means of immigration is unknowm, but 
fruiting calyces of these salt-mai*sh species can stand prolonged immer- 
sion in sea-water and they could be carried by the Gulf Stream across 
the Atlantic Ocean. Alternatively, the hairs on the ribs of the calyces 
make it likely that fruiting-calyces will adhere to the feathers of birds 
frequenting salt-marshes, one possible carrier being the Greenland 
White-fronted Goose. 
L. humile occupies a pioneer position in the salt-marsh succession; 
an ecological niche in which competition would not be severe for a suit- 
able immigrant. 
H. G. Baker. 
Orchids from Guatemala and some Interesting Plants from Arizona. 
Miss F. M. Barton. 
ONONIS HKGLINA TA 
Specimens of 0. reclinata 1j. were exhibited from the Gower 
Peninsula, Glamorgan. The plant was discovered in June 1952 
near its old haunt, where according to information supplied by 
Mr. J. E. Lousley, it has apparently not been recorded since 1828. 
Only a small patch was located, and time unfortunately did not allow a 
more intensive search to be made. 
Miss M. H. Bigtvood. 
Distribution of ALOTIEMILLA Micro-species in the Teesdale Area 
The exhibit showed detailed dot-distribution maps, based on the 
1" O.S. (with National Grid), for five rare or local Alrhemilla micro- 
species in the Teesdale area. The work, though naturally incomplete, 
is revealing interesting differences in detailed distribution, and should 
provide a sound basis for any speculation on the significance of the 
Teesdale AlchemiUa concentration. 
It is hoped eventually to publish the maps in suitable form. 
Miss M. E. Bradshaw & S. M. Walters. 
