Critical Plants noticed on the Excursion. 403 
Rouy FI. France, iv, 96 (1897); but the position and the characters 
of the plant suggested that it might have had a hybrid origin. 
However, other of the forms in question may he good species or 
varieties, for it seems certain that forms may arise either as true 
varieties or by hybridisation, and yet closely resemble each other. 
As Professor Drude truly states (p. 237 (1912) ), “the complexity of 
the subject has naturally been increased by new phylogenetic and 
ecological studies ”; and this complexity seems more likely to be 
increased than diminished as time goes on. There is certainly need 
here, as in many similar cases, for experimental work. 
Ulex Gallii Planchon Ann. Sci. Nat. ser. 3, xi, 207, t. 9 (1849). 
It will come as a shock to British botanists to know that this plant 
is, in Ascherson and Graebner’s Syn. vi, pt. ii, 288 (1907), reduced 
to a hybrid of U. europceus and U. nanus (or U. minor). Of course, 
the distribution in this country of our three species of Ulex is wholly 
against such a view; and I am sure that no British botanist will 
agree with or sympathise with the hypothesis of the hybrid-nature 
of U. gallii. Rouy et Foucaud (FI. France, iv, 243 (1897) also 
definitely reject the theory that U. gallii is a hybrid. As the plant 
is confined to France and the British Isles, the deliberate and 
unanimous verdict of French and British botanists should surely be 
accepted. However the plant was seen in many places on the 
excursion, so that the members had an opportunity of arriving at an 
independent conclusion. 
I may add that U. europceus occurs throughout Great Britain, 
usually at altitudes below about 250 metres ; that U. gallii gets no 
further north than southern Scotland, and usually ascends 100-200 
metres higher than U. europceus; and that U. nanus is decidedly 
rare and local north of the Thames valley, has its northern limit in 
central England, and is a more pronounced lowland species than 
even U. europceus. In Ireland, both U. eicropceus and U. gallii 
are widespread and locally abundant; and U. gallii usually occupies 
a higher zone than U. europceus, U. nanus is unknown in Ireland. 
It will be seen that the distribution of the three species gives no 
support whatever to the view that U. gallii is a hybrid. 
Pyrus aucuparia L. [. Pyrus aucuparia “var. (orforma )” jlava 
Druce in New Phyt. x, 312 (1911) nomen; Sorbus aucuparia 
xav.jlava Ostenfeld op. cit. xi, 120 (1912) nomen.] Pale-fruited forms 
are very interesting from the standpoint of the study of evolutionary 
variation; but it is a question whether they, and also the colour- 
variations in petals, should receive formal systematic names. 
