ON THE GENUS RUBUS. 49] 
distinct line to separate the aculei and aciculi. In some Rubi we 
find very small prickles, proportionally as much expanded at the 
base as the larger ones: these I should not call aciculi. For the 
most part the prickles of the flowering-branches are smaller than 
those of the barren shoot. The stems are also often free from 
prickles ; but sometimes these organs extend into the panicle, and 
are even very stout and large on the flower-stalks and calyx, much 
stronger even than on the other parts of the plant, in proportion 
to the solidity of the parts on which they grow: those on the 
leafstalk are usually more hooked and proportionally larger than 
those on the stem, and these extend more or less on the midribs 
of the leafits. 
Besides prickles, aciculi, and setz, we find on some Brambles 
a few sessile glands; but these seem rather to occur accidentally 
in many species than to form a peculiarity in one, and no use of 
them has been made in forming specific characters; they are 
rarely even mentioned in the more detailed descriptions. 
The hairs on the stem are of two sorts. In some plants they 
are short, stellate, nearly adpressed to the stem, and forming to 
it a close greyish covering. In others they are longer, single, and 
spreading, often horizontally. This latter sort seems more vari- 
able than the other, but they are neither of them so constant as 
to be depended on as marks of species. We sometimes find both 
on the same stem. The sepals are usually covered with hairs of 
the first sort. 
On the leaves we find the same difference in the disposition of 
the hairs,—a very close, stellate, penicillate, or at least entangled 
pubescence of very fine hairs, and larger and spreading hairs. In 
R.tomentosus the former is observable on the upper side of the 
leaf, forming an even, grey covering, but in general the upper 
side of the leaf in Brambles has only a few scattered hairs along 
the midribs and primary veins, and no general covering. On the 
other hand, the under side is, I believe, always hairy. The shorter 
hairs occur in some species, and not in others; sometimes show- 
ing the under side of the leaf as quite white, sometimes as grey, 
and sometimes as pale green. ‘This difference depends partly on 
the covering over the greenish surface of the leaf beg more or 
less dense, but partly, I believe, on the colour of the hairs them- 
selves. The longer hairs are hardly ever entirely wanting. They 
rise from the ribs and veins, rarely from the surface of the leaf, 
