34 
its junction with the Airyholme branch, in company with S. alba and 
other species. The third station is on the bank of the same stream, 
considerably nearer the village of Great Ayton, and has been noted 
for the last thirty or forty years as producing the “ black sallow.” 
Previously to 1840, three well-grown trees were in existence in this 
locality ; but about that date they were each cut down to the ground, 
by a resident labourer, who was, doubtless, unaware of the damage 
he was committing. But, fortunately, from the remains of one of 
them a sucker sprung up, which has by this time grown into a tall 
bush, which flowers periodically ; so that the station was not entirely 
destroyed. From this alone, a staminate plant, have flowering speci- 
mens been procured. 
Almost all diversified and intricate genera appear to subdivide 
themselves into groups or sections, each composed of species more 
intimately allied to each other than to the members of any other 
group, which, as it were, radiate from primary or typical species as 
from acentre. Being natural in their character, these may usually 
be understood without difficulty ; and when once appreciated they 
are of infinite assistance in gaining a correct idea of species. But, 
when the species possess a wide range of variation, it is almost impos- 
sible to decide with certainty how many each group contains; or 
whether a series of forms comprises a group of species, or a single 
species only. This is eminently the case with the genus Salix. The 
group to which the Cleveland willow belongs (Pruinose, Koch) may 
easily be distinguished. The plants which it comprises are charac- 
terized by sessile lateral catkins, the scales of which are discoloured 
at the tip, by yellow anthers, by the pale yellowish hue of their inner 
bark in the summer and autumn, and by the glaucous bloom which 
usually covers their branches, especially in a dried state. They are 
trees, or tall shrubs, with long, wand-like glabrous or hairy branches ; 
lanceolate-acuminate, glanduloso-serrate leaves, usually downy when 
young, but invariably glabrous and indurated when fully matured ; 
narrow female catkins, with subsessile ovaries, elongate styles, and 
linear-oblong stigmas ; and broad, blunt male aments, the flowers of 
which each possess two free filaments. By Koch this group is placed 
third in order, between the Amygdaline and Purpuree. In the 
arrangement of Fries it composes, with S. lanata, S. Lapponum, and 
other species which do not inhabit Britain, the second section of his 
subgenus Vetrix, which also includes the Viminales with S. acumi- 
nata and S. holosericea, Willd. In the Willdenovian ‘ Species Plan- 
