On Stipules, their Forms and Functions.-Part II

John Lubbock
1895 Journal of the Linnean Society of London Botany  
fringed at the margin and traversed by branching veins. The THEIR EOBMS AND FUNCTIONS. 465 secondary stipular sheaths are much smaller than in T. apuilegifolium. Ranunculus apatilis, Linn., var. pseudo-fuitans, 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,
more » ... as t o 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 Ranunculaces an arrangement very similar to that Qf the Potarnogetons. DILLENIACEB. Bibbertia volubilis, Andr.-Tbe 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 j 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 corers 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. Groom ( Trans. Linn. SOC. ser. 2, Bot. vol. iii. p. 263) describes and figures bud-protection in Wormia Burbidgei, 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 triyuetra, Rottb., by the adnate stipules. The tree is therefore but sparingly branched. 466 SIR JOIiN LUBBOCK ON STIPULES, MAGXOLIACEB,. This order is one of those in which some species have, and others have not, stipules. As already mentioned (Journ. Linn. SOC. vol. xxviii. p. 223) the winter-buds in Xadszlra are protected by the outer leaves, which are reduced to scales. In Drimys a few of the outer leaves of the resting-bud are reduced to small bractlike fleshy organs, which become green or red on the resumption of growth. The leaves i n bud are convolute, two of the outer ones enclosing the rest. I n Magmolia acu!tizinata, Linn., the stipules are adnate to the petiole for only half its length, and in M. grandgora, Linn., at the very base only, connate at both edges, forming a cylindrical sheath, which encloses the bud, gradually splitting as the latter develops. The interesting case of Liriodendron I have already described (Journ. Linn. Soc., Bot. vol. xxiv. p. 84). I n Maspaolia glauca, Linn., the winter-bud is covered by a pair of connate stipules adnate t o a petiole that is less than half their Lactoris is included 'by Bentham in Piperaces. BERBERIDEB. I n Lardizabala hiternata, Ruiz et Pav., stipules are absent, but the leaves of axillary shoots appear like Btipules. When the shoots with their evergreen and leathery leaves are fully matured, the buds in the axils of the leaves swell up and produce a small, simple, obliquely-ovate or cordate leaf ripht and left of the axis. LINN. J0URN.-BOTANY, VOL. XXX. 2 1,
doi:10.1111/j.1095-8339.1895.tb02421.x fatcat:qjjqt5myjnfjtkx7vi6ncjuwqe