GIO SUMMARY OF CURRENT RESEARCHES RELATING TO 



Embryo-sac of Rosacese.* — M. F. Went states that the study of the 

 embryo-sac of the EosacciX3 is iutcrcstiug, as it leads cue to the opinion 

 that cither the Eosacena and Saxifragaccas have a common origin, or that 

 the Eosacc.TB have descended from the fc^axifragaceaj. The chief difference 

 between these two families is the fact that the Saxifragaccae possess 

 endosperm; but if one examines the Spira3ca>, certain rudimentary traces 

 of endosperm will be found when the seeds arc ripe. The Spiraeeso then 

 form the point of transition between Saxifragaccfc and Rosaceae. The 

 author then, beginning with Prnmis, describes the form of the embryo- 

 sac in various members of the Rosacea;, especially pointing out to what 

 extent endosperm is present. 



Petiole of Dicotyledons.f — M. L. Petit describes the structure of 

 the petiole in various Dicotyledonous families, and gives a table showing 

 the jirincipal differential characters of this organ. The author, in his 

 conclusions, states that the study of the course of the fibrovascular 

 bundles in petioles has been very much neglected. It is useful, however, 

 because of the fact that it is possible to group the numerous objects 

 which are studied under a small number of types. The general law on 

 the disposition of the fibrovascular bundles is, that in herbaceous plants 

 they are usually isolated, -while in woody plants they are in close 

 proximity to one another. The author insists on the importance of the 

 petiole for purposes of classification. 



Development of Flowers in the Bud.| — 1\I. Louis Mangin states 

 that organs generally present two phases of growth. In the first phase 

 the organ acquires a certain structure, the dimensions of which are very 

 restricted ; but in the second phase, an energetic intercalary growth takes 

 place, and the organ arrives at the adult state without sensibly modifying 

 its structure. In this paper, the author records a series of observations 

 on the development of flowers. The fruit trees were first studied on 

 account of theii- earliness of flowering, and of the ease with which flower- 

 buds can be distinguished from leaf-buds. 



If a longitudinal section of a flower-bud of the cherry, taken about 

 the 23rd of June, be examined, the gi'owing point will bo found to be 

 protected by four or five layers of scales. A month later the growing 

 point will be found enlarged ; the apex, however, now ceases to grow, but 

 round the apex a certain number of cellular papillae are formed, each of 

 which represents a flower. On the edges of the hollow papillao five 

 protuberances will be found ; these represent the calyx, the hollow 

 portion of the papillfc forming the floral receptacle. About the 16th of 

 August, the base of the calycine protuberances will be found to have 

 enlarged so as to form a tube ; on the internal face of this tube, at the 

 base of the indentations separating the calyx-teeth, appear the emergences 

 which represent the petals. Finally, at the base of the receptacle, 

 which has been up to the present time empty, arises the protuberance 

 which is to form the carpel. 



The author then traces the growth of the ovules, formation of the 

 pollen, and origin of the bundles, and concludes by comparing the 

 development of the flowers of other members of the Amygdaleae with the 

 cherry. 



* Auu. Sci. Nat. (Bot.), vi. 1887) pp. 331-41 (1 pi.). f Ibid., pp. 342-54. 



X Morot's Journ. Bot., ii. (1888) pp. 1-7, 20-30 (22 figs.). 



