4 The Nature and Origin of Stipules. 



De Candolle, A ugustin P. — Organographie Vegetale, 1 ; 334-341. 



1827. 



De Candolle's views as here expressed may be 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 exactty the character of leaves that we can saj r that they 

 are small accessory leaves. 



" In certain verticillate leaves, such as those of Galium, it is 

 noticeable that the buds and young branches are not produced in 

 the axils of all the leaves, but only of two among them which are 

 opposite to one another. I presume that these two leaves 

 furnished with buds are the true leaves and that the others should 

 be considered as foliaceous stipules. 



" The natural use of stipules seems to be the protection of the 

 leaves during their development, but we must admit that in man}' 

 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 Cucurbitacese 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 saj^s 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. 



" 1. Buds are called foliar when, the leaves being sessile, the 

 blade itself, reduced to the form of a scale, forms the buds, as in 

 Daphne mezereum L. 



" 2. They are called petiolar when the bases of the petioles dila- 



* See also A. Richard. Precis de Bot., 126. 



