A REVIEW OF IMPORTANT LITERATURE PERTAINING TO STIPULES.
Owing to the fact that a large part of the literature pertaining to stipules is inaccessible to the majority of botanical students, scattered as it is, for the most part, in the journals of various scientific bodies, it has seemed desirable to preface the considera tion of the results of Iny research on the question of the Nature and Origin of Stipules with a brief summary, iu chronological order, of the publications having reference to the general subject of stipules. .1 have, however, omitted mention of their consideration in systematic works and the general allusions and definitions as they occur in most general works on the Spermatophyta together with their special consideration in individual species and groups except in the most important eases.
Stipules have not received a very large degree of attention from botanists apart from their morphology as used in classification and the publications to be considered are not very numerous, but it is thought that a review of those following will be profita ble and of general interest : Malpighi, Marcello.—Opera (mania, 22-39. 1686.
This is one of the earliest works in which stipules are treated. A considerable number are figured and described under the name of foliola caduca.
A. general definition is given of stipules as scales borne at the base of the petiole. Buds are spoken of as formed by stipules, by petioles, or by rudiments of leaves.
The stipule is defined as a foliaceous appendage or accessory leaf situated at the base of certain leaves: The stipel, first so named by De Candolle, is defined as a stipule placed on the com mon petiole at the base of the leaflets.
De Candolle's views as here expressed may he outlined as fol lows : " Stipules do not exist in any monocotyledonous plant,* nor in any dicotyledons in which the petiole has a sheathing base ; among dicotyledons with leaves not sheathing, stipules are fre quently wanting, especially in plants with opposite leaves. Their existence is intimately connected with the general symmetry of plants, and they occur or are wanting in all the species of a family.
" The only essential character of stipules is their lateral position at the base of the leaves, and it is not impossible that we confound under a common name objects really distinct. Their texture is, in many plants, perfectly foliaceous and in these cases they ex hibit so exactly the character of leaves that we can say that they are small accessory leaves.
" The natural use of stipules seems to be the protection of the leaves during their development, but we must admit that in many cases their smallness or their nature or form make them inappro priate to this use, though we cannot well assign another to them, those which are foliaceous assist in the elaboration of the sap, those which are changed into spines serve for the defense of the plant.
" The tendril in the Cucurbitacem is perhaps a modified stipule. The ochrea of Polygonums is a prolongation of the base of the petiole into connate stipules." In volume 2, pages 213 and 214, De Candolle says in treating of buds, " They have received particular names according as they are formed by different parts of the foliar organs, and according to the degree of their degeneration and adnation.