The Nature and Origin of Stipules. 9 



JiiSSieu, Adrien. — Cours d'Histoire Naturelle: Botanique. 108-111. 

 1852. 



Speaking of the leaf-sheath, Jussieu sa} r s that " sometimes the 

 vascular bundles converge little by little, and there is a gradual 

 transition from the sheath to the petiole ; sometimes the marginal 

 bundles stop after a course varying in length, or are prolonged 

 in another plane than that of the petiole, and then there is a clear 

 distinction of petiole and sheath. Often, however, the paren- 

 chyma does not unite the lateral bundles to the central ones 

 which continue in the petiole, and this is the probable origin of 

 many stipules." 



Trecul, A. — Sur la Formation des Feuilles. Ann. Sci. Nat. (Ill), 20 : 

 288-299. 1853. 



The usual classification of stipules is given with the addition 

 of extra-foliar stipules to include those of Nelumbium. The au- 

 thor says, " In all adnate stipules that I have seen, they do not 

 envelop the leaf to which they belong, but that which comes next 

 after them, and their own leaf is protected by the stipules of the 

 leaf preceding. Under these circumstances the stipules play the 

 same role as the sheath, from which they differ very little. We 

 see thus clearly that there is the closest analogy between the for- 

 mation of adnate stipules and that of a sheath ; the analogy is 

 such that it is impossible to distinguish between them in princi- 

 ple." All the forms of stipules, the ochrea, the tendrils of Smi- 

 lax and the ligule of grasses are classed together. 



Among the conclusions those relating to stipules are as follows : 

 In basifugal leaf-formation all the parts are formed from below 

 upward, the stipules first of all. In leaves with basipetal forma- 

 tion, the stipules have their origin earlier than the lower parts of 

 the blade and sometimes even before the upper. 



Trecul, A. — Vegetation du Nelumbium codophyllum. Ann. Sci. Nat. 

 (IV), 1: 291-298. 1854. 



In the seedling of this plant the leaves are in two ranks on the 

 upper and lower sides of the rhizome and each of them is pro- 

 vided with an axillary stipule. In its later stages the leaves of 

 the lower rank are aborted with the exception of the stipule of 

 every second one and in the upper rank every second leaf is rep- 

 resented by the stipule onty. The internodes above the stipules 

 which stand alone remain undeveloped so that three stipules are 

 associated with each leaf, one axillary and two extra-axillary. 



