THEIR FORM AND FUNCTION. 243 
on the function of the leaves themselves, sometimes they become 
spiny and serve as a general protection to the plant, sometimes 
they are glandular, &e. 
The view here suggested seems to apply well both to the 
cases where the stipules are very short-lived, and also to those in 
which they are very persistent. When they serve, and serve 
only, to protect the leaves to which they themselves belong, they 
often fall off when the leaves themselves expand. On the other 
hand, there are cases where they protect the following leaf or 
leaves, as for instance in Magnolia, Liriodendron, and other 
Magnoliaceæ. When the stipules of the terminal leaves of one 
year protect the next leaves, which do not emerge till the 
following year, they are much more persistent than the leaves 
themselves. Both cases sometimes occur in the same family. 
This, then, is the answer I should give to M. Vaucher’s 
question, and the presence or absence of stipules is not deter- 
mined I think, as suggested by DeCandolle, by any question of 
general symmetry, but rather by practical considerations con- 
nected with the wants and requirements of the plants.* 
LIST OF FIGURES. 
Fig. 1. Shoot of Helianthemum vulgare. 
Fig. 2. Shoot of Helianthemum ælandicum. 
Fig. 3. Shoot of Cistus cyprius. S, S. Connate sheaths of leaves. 4, 4. Axil- 
lary shoots. 
Fig. 4. Shoot of Leea coccinea. P. Petiole of leaf, the lamina being cut off. 
S. Stipule. L. Young leaf emerging from stipules. 
Fig. 5. Shoot of Spartium junceum. A. Nat. size; B. More magnified to show 
the bud protected by the pedestal of the fallen leaf. 
Fig. 6. Shoot of Acacia verticillata. S, S. Stipules. 
Fig. 7 a. Leaf of Nuttallia cerasiformis, with entire sheath. 
Fig. 7 b. Leaf of Nuttallia cerasiformis, higher up, showing indications of stipules 
Fig. T c. Leaf of Nuttallia cerasiformis, with stipules in ultimate form. 
Fig. 8 A. Ribes sanguineum. Outer bud-scale with 3 vascular bundles ; stipules 
indicated by lateral teeth at the tip. 
Fig.8 B. Ribessanguineum. Yurer bud-seale, with broader membranous margin. 
Fig. 8C. Ribes sanguineum. Intermediate form between bud-scale and leaf. 
Fig. 9. Ribes sanguineum. Leaf higher up. S. Stipule. 
Fig. 10. Ribes sanguineum. A third stage, showing stipules reduced to an 
adnate sheath, S. 
Fig. 11. Shoot of Bucklandia populnea. S, S. Stipules. P. Petiole. 
* In the preparation of this paper I have relied mainly on the facilities 
afforded by Kew Gardens, and I desire to express my thanks to the late and 
present Directors, Sir J. Hooker and Mr. Thiselton Dyer, and indeed to the 
Staff generally. 
