STRUCTURE.] ORIGIN OF STIPULES. 277 



lateral lobes continuous with the lamina, which is as yet 

 without a petiole. 



In these two, as well as in all other cases, the stipules of 

 the rudimentary leaf appear as portions of the blade ; and it 

 is not till later, in consequence of the development and 

 elongation of the petiole, that they are at a sufficient distance 

 to be considered as distinct organs. 



In all simple leaves, stipules never appear with the first 

 rudiments of the blade ; they are developed with the lower 

 parts of the blade which generally contain the petiole. . 



In compound leaves, stipules are found on the youngest 

 part of all the leaf. 



In Melianthus major, the stipules do not appear before the 

 leaf forms a distinctly lobed organ. They are first seen as 

 an annular rim between the axis and the base of the leaf. 



In Leguminous plants (Lathyrus venosus, Pisum sativum, 

 Medicago sativa, &c.) the stipules are originally found 

 situated in a point nearly vertically below the top of the 

 axis -j and it is only later that they are found pushed towards 

 the edges. All leaflets otherwise situated never become 

 stipules. So long as the leaflets of a leaf are not evident as 

 lobes or toothings, no trace of stipules can be found, but in 

 time they appear on the axis as projecting points. In 

 certain cases they do not appear, until the lobes, which 

 eventually become leaflets, begin to form laminse. 



In Roses, no stipules appear until the leaf is sufficiently 

 developed so as to look like a simple crenated leaf. The edges 

 of the basal toothings extend on the periphery of the axis, 

 they then rise into rims which become in their turn toothings 

 and attach themselves on each side to the old ones. Later, 

 and in consequence of the development of the petiole, these 

 lower toothings, which are gradually being transformed into 

 lobes, become separated from the upper ones, and it is not 

 until then that they constitute stipules. 



The leaves of Costus speciosus are composed of a blade, a 

 short petiole, and a closed sheath, crowned on its upper edge 

 with a membranous, lacerated pellicle analogous to a ligula. 

 On examining its buds and removing five or six rudimentary 

 leaves, the nucleus of the axis is found to be surrounded by 



