THEIR FORMS AND FUNCTIONS. 465 
secondary stipular sheaths are much smaller than in 7. aquilegi- 
Solium. 
Ranunculus aquatilis, Linn., var. pseudo-fluitans, Syme.—The 
aquatic Ranunculi, of which the above may be taken as a type, 
differ from the land-forms as regards the arrangement of the 
stipules, which are adnate to the petioles, with ovate or triangular, 
obtuse, free auricles or tips. They are membranous and attached 
all round the axis, so as to form a sheath. The terminal bud is 
enclosed by the stipules of the two uppermost expanded leaves. 
The developing leaves push their way out at the apex of the 
stipular sheath. Similarity of conditions have therefore developed 
in the aquatic Ranunculacee an arrangement very similar to that 
of the Potamogetons. 
DILLENIACEE. 
Hibbertia volubilis, Andr.—The leaves are exstipulate and 
shortly petiolate; the petiole is winged, articulated with a pedestal 
which is dilated, carried round the stem, and connate, forming a 
cup, which is obliquely one-sided, being very shallow at the point 
of union of the posterior edges. The leaf is conduplicate in bud, 
and the lamina unfolds first. The terminal bud is protected by 
two leaves; mainly by the oldest unexpanded, but partly by the 
youngest expanded leaf. The pedestal protects the base and the 
axillary buds; it persists a long time, even for years, after the 
leaf has fallen. In H. dentata, R. Br., the petiole is deeply 
channelled, but not winged. 
In Dillenia indica, Linn., the terminal bud is surrounded by the 
concave and sheathing petiole of the last developed leaf, or that 
of one in the process of expansion. A small portion of one other 
leaf is exposed, but all are densely silky, attaining considerable 
size before expansion, and each in turn clasps and covers the next 
younger leaf more or less completely. 
Axillary buds are seldom developed, although they form under 
the sheath of the petiole and are densely clothed with glossy pale 
brown hairs. The tree is therefore but sparingly branched. 
Groom (Trans. Linn. Soc. ser. 2, Bot. vol. iii. p. 263) describes 
and figures bud-protection in Wormia Burbidget, Hook. f., where 
the leaf-sheath (? adnate stipules) forms a cylindrical chamber 
enclosing the bud. 
Potter (Journ. Linn. Soc., Bot. vol. XXViii. p. 346) describes and 
figures the bud-protection in Wormia triquetra, Rottb., by the 
adnate stipules. 
