990 SUMMARY OF CUUKENT RESEARCHES RELATING TO 



((•) In species of Salix, in Viburnum Opulus and V. opulifolium, tlic first 

 pair of leaves grow together to form a completely inclosed iirotcctivo 

 sbeatb. (<?) A similar sbeatli, mor[tli(>liigically referable bowcver to tbo 

 stipules, is exbibitcd by tbc buds of Platanus and Magiioliaceae. Tbis 

 ocbrca arises by true fusion of tbc stipules of aborted main leaves in 

 riatauus, by apparent fusion in MagnoUa and LiriodemJron. (e) In 

 stipulate plants tbo stipules usually share in the equipment of tbo 

 buds. Exceptions are found in trees with very much reduced stipules, 

 as Euonymns, Ailanthus, and Vibuynum Lantann. In the si)ecie8 of 

 Jhnis, the protection is essentially restricted to tbo stipules of a 

 developed main leaf of the daughter-bud. Petteria ramentacea exhibits 

 another modification of stipular protection. 



II. As a summer protection, some plants have utilized the leaf-base, 

 which either incloses tbc axial bud like a cap, or covers it like a 

 cushion. The first mode is seen in Virgilia lulea, Bhus glabra, Robinia 

 viscosa, It. hispida, li. Pseudacacia, Platanus, and some of the Pbiladel- 

 ])hace£e. The hitter is exhibited in the species of Gleditschia, Sophora 

 japouica, Ptelea mollis and trifoliata, Menispermum canadensc, Aristo- 

 lo:hia )<iplio, Negundo aceroides, CalycanOius floridus and occidentalis. 



The separation of the subtending leaf takes place in llobinia, Meni- 

 spermum, most Pbiladelpbacejc, and in Gleditschia, in such a way that 

 the many-layered leaf-base covers the bud in winter. 



An effective winter and summer protection is afforded in Kahnia 

 latifoUa and Spartianthus junceus, by a leaf-stalk which completely 

 conceals the resting buds. In many plants (Papilionaccjc, Amygdalaceaj, 

 Eosaceai), the leaf when it falls leaves an articulation behind. 



III. The bark may also function in preserving the buds. This pro- 

 tection may be a summer one, produced by the leaf-base, as in 

 Xanthoxylon Bungei, Sopliora, SJcimmia, Gleditschia, Phellodcndron 

 amurense. When the cortical tissue protects the buds also during 

 development, the modification occurs in very young stages when the 

 subtending leaf is still in the byponastic state. This is seen in Aclinidia 

 colomicta and A. polygama, Cephalanthus occidentalis, and Gi/mnocladus 

 canadensis. 



IV. Finally, the hairs furnish effective protection. They serve 

 either to augment protective modifications of another nature, or they 

 may by themselves discharge the greater part of this function. Hairy 

 protections may be well seen in Virgilia lutea, Gymnocladus, Viburnum, 

 Lentago, Pterocarya, &c. 



Development of the Flowers of the Mistletoe.* — Herr L. Jost has 

 minutely followed out the development of both male and female flowers 

 in Viscum album, comparing it with what is known in other species be- 

 longing to the Loranthacefe. The general results arrived at are that the 

 organs of reproduction of both kinds are greatly reduced in structui-e. 

 The ovules are reduced to single macrospores or embryo-sacs which are 

 formed at the end of the axis of the flower ; the anthers or microspor- 

 angia arc not placed on special staminal leaves, but on the perianth. In 

 their structure they bear a closer resemblance to those of some Vascular 

 Cryptogams than to the androecium of most Angiosperms. 



In the development of the female flowers, the mother-cells of the 

 embryo-sacs are produced in considerable numbers, a common number 



* Bot. Zrg., slvi. (1888) pp. 357-68, 373-87 (1 pi.)- 



