THEIR FORM AND FUNCTION. 241 
sheaths may perhaps be regarded as adnate stipules, and the tips 
are often more or less free. 
ARALIACER. 
In the Ivy (Hedera) stipules are present, but small. In 
conjunction with the dilated and amplexicaul bases of the 
petioles they cover the young leaf. The winter-buds are pro- 
tected by scales, consisting of the base of the petiole with its 
stipules. 
In Acanthopanax (A. spinosum) the stipules consist of a 
narrow, membranous, colourless margin to the petiole, and this is 
cut up into brown fringes. The winter-bud is protected by 
scales as in Hedera. The petioles are subterete. In Helwingia 
also the stipules are filamentous, often irregularly laciniate. 
CORNACER. 
In Griselinia (G. lucida) the stipules form an intrapetiolar 
sheath, somewhat resembling the ligule of grasses. The petiole 
is subterete, or slightly dilated at the base. 
CAPRIFOLIACES. 
I have dealt with the interesting stipuliform appendages of 
Viburnum Opulus and some of its congeners in a separate paper 
(infra, p. 244). In Sambucus also (S. nigra) the stipuliform 
appendages are semiterete, and glandular at the tip. The winter- 
bud is protected by scales. 
APOCYNACER. 
The Apocynacex are generally described as exstipulate, but 
Strophanthus (S. dichotoma) has rather large stipular processes. 
The petioles are slightly grooved above, united by a ridge crossing 
the stem horizontally, which appears to form a small socket 
into which the next joint of the axis fits. Within the petioles 
this ridge is continued and becomes there drawn out into a 
triangular acute stipuliform process. The function of these 
intrapetiolar processes is evident on examination of the terminal 
bud which they protect in the early stages, gradually opening as 
by two valves. The next younger pair of leaves decussating with 
those bearing the stipular processes have their sides protected 
for some time by the latter, their stout midribs becoming first 
exposed. The stipular processes are persistent and ultimately 
become brown. 
