162 Mr. Woops on the British Species of Rosa. 
his having used the words aculeatus, setosus, and hispidus, as applied 
to the fruit and peduncle; but he extends the difference no 
further, and has given no explanation of the particular meaning 
he attaches to these terms. © = = on 15 
Roses are furnished with aculei, sete, glands, hairs, chaff, and 
pubescence. Aculei or prickles are sometimes hooked, and gene- 
. rally more or less curved; but in some species they are quite 
Straight. They have an expanded oblong base, and occuron the 
stems, petioles and nerves of the leaves, and perhaps in one or 
two instances on the fruit and fruit-stalk ; at least one variety of 
R. spinosissima is either furnished with aculei, or with setze so strong 
that they are very liable to be mistaken for aculei. 
Acute are either straight, as in R. spinosissima ; straightish, 
with a very slight curve downwards, as in R.villosa ; falcate, or 
bent as a scythe, as in the large prickles of R. gracilis, and in 
some varieties of R. tomentosa ; and hooked or uncinate, like a — 
claw or sickle, as in R. canina. : Those of R: arvensis and of some 
neighbouring species are frequently a sort of obtuse elliptical cone, 
with a straight or curved mucro. This peculiarity of form is not 
found in R. systyla, and is no where sufficiently constant to enter 
into the character of any species. In the descriptions of the species, 
the form of the aculei must be taken from those which grow on 
the strong parts of the plant, and from those which are largest 
and with the most extended base. Ha raf 
‘Ser# are always straight, and tipped with a gland ; this gland 
sometimes falls off, but vestiges of it can generally be perceived. 
Setæ are always smaller than aculei occupying the same situa- 
tion; that is, the sete of the stem are smaller than the aculei of 
the stem ; the sete of the petioles are smaller than the aculei of 
the petioles; but the sete: of the stem are often larger than the 
„aculei 
