In individual leaf development in the Stellatre, the whorl originates in a uniform ring about the growing point. Then arise two opposite prominences in the ring. These develop into the true leaves. After them appear two smaller prominences on each side of the stem between the first. These are the stipules. Ac cording to the species they develop separately, forming six-leaved whorls, or grow together giving origin to four-leaved whorls.* *With this view Gael agrees (Schenk's Handbuch der Botanik 3 : 230. 1884), except that he does not distinguish the time of appearance of the differ ent parts of the whorl.
Where a larger number of leaves occurs, au additional prominence for each arises between the original stipnlar prominences.* Ca uvet, de la Presence des Stipules dans quelques Mono cotyedones. Bull. Soo. Bot. Fr. 12 : 241. 1865.
A number of cases are considered and the conclusion drawn that very probably some Monocotyledones are provided with stipules, but the difference in their form and position has caused them to be considered as another kind of organ.
Mr. Meehan argues for the origin of the stipules of Magnolia as lobes of the lamina similar to the auricles which occur in M. Fraseri Walt. by a union of the auricles with the upper surface of the petiole, and a subsequent actuation of their margins and separation from the lamina. He says, " It is scarcely possible to avoid the suspicion that the stipules of Magnolia are not formed like the stipules of most plants which are perhaps leaf portions which have never been well developed, but rather are the tolera bly well developed side pinnules of a trifoliate or deeply auricled leaf." Speaking of observations upon the flowers of M. fuscata Andr., of East India, the following interesting statement is made : " This observation confirms the views of some botanists as 1 have learned from Professor Asa Gray, that it is by metamorphosis of the petiolar and stipular parts, rather than by modifications of the leaf-blade, that petals are formed." quelques tissues de Joncks, etc. Bull. Soc. Bot. Fr. 18 : 231-239. 1871.
The presence of the ligule in the Jimca.cea. is treated of. To quote the author, " If in certain species the ligule is so reduced that it appears to be lacking between the separated auricles at the apex of the sheath, in most others these auricles are united by a true ligule, as pronounced as that of grasses, either entire or cleft at the middle."
Detail)', les variations de structure de la ligule des Graminks. Bull. de la Soc. Linneene, 170. 1878.
*F. Pax (Allgemeine Morph. der Pflanzen, 100. 1890) says, when there are more than six parts to the whorl, the additional parts must have their origin in a division of the blades of the stipules.
It is argued from the presence of a median vein in the ligule of some of the grasses in which this organ is supplied with vascular support that it cannot be formed of two stipules grown together.
The functions of stipules as protecting organs are discussed. They are considered under the heads of (1) those protecting the buds in winter, (2) those protecting the growing parts in the spring, (3) those which serve as protection against insects and other animals, (4) those which serve as well the function of as similation.
The adaptation of most stipules in their form and manner of growth to the special function they are intended to fulfill and the apparent lack of function in others is remarked upon.
This paper is the first part of an extended consideration of the subject of stipules. It deals with their occurrence in the families of plants and their importance in classification on account of the great variety of their characteristics.
Clos, D.—De la part des Stipules a l'infloresence et dans la Fleur. Comptes Rendus, 87: 305-306. 1878.
The stipular nature of the sepals in Geranium, Helianthemum, Begonia, Oxalis, Alehimilla, Viola and many other genera in dif ferent families is maintained.
Attention is called to the anomalous connation of the stipules of Spergularia marina Griseb. exterior to the petioles of the opposite leaves.