Jussien, d'Histoire Naturelle: Botanique. 10-111. 1852.
Speaking of the leaf-sheath, Jussien says 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, la Formation des Feuilles. Ann. Sci. Nat. (III), 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 oehrea, 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.
Treen1, 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 tipper rank every second leaf is rep resented by the stipule only. 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.
One of these last is on the upper side of the rhizome external to the leaf, the other on the lower side.
This paper was presented before the Botanical Society of France, May 24, 1854. M. Ad. Brongniart took part in the dis cussion which followed. He agreed with Trecul in his conclu sions and closed with the statement that " this arrangement re calls that of certain buds in which the scales result from the stipules of leaves of which the petiole and blade are alike aborted." M. F. J. Lestiboudois remarked that " to decide whether stipules are an integral part of the leaf, it is necessary to study them anatomically. In other plants the same fibro-vas cular bundles are distributed to the leaf and stipules. Stipules should therefore be regarded as appendages of the leaf." Clos, D.—Considerations sur la Nature du praendu Calicule ou involucre des Malvacees. Bull. Soc. Bot. Fr. 1: 289-303. 1854.
The stipular nature of the parts of the involucre or exterior calyx in the Malvacete is asserted contrary to the views of Aug. St. Hilaire (Lecons de Bot. 372. 1840) and the term stipulium is suggested as applicable to it.
The term stipulium is applied to the exterior calyx of the Mal vace.e and the involucre of the umbel of some Geraniacete. In the Cistace2e the bractlets of the calyx are wanting in exstipnlate species.* In many of the Leguminoste and the bracts are evidently formed by stipules.
The different theories regarding the tendril in the Cucurbitacete are briefly stated. They have been considered to be roots ; abor tive peduncles by Tassi ; stipules by De Candolle, Stoks and Aug. St. Hilaire; leaves by Gasparini, Seringe and Braun ; degenerate branches by Meneghini ; superfluous branches by Link; terminal branches of the axis as in Vitacete by Fabre ; partly leaf, partly branch by Naudin. Clos concludes that the tendril arises by a division of the leaf, three fibrovasenlar bundles entering the leaf when there is no tendril and two when the tendril is present and receives the third bundle.