G2 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Anatomy of the Geraniacese.* — A. Legault has studied the anatomy 

 of the vegetative organs of the Geraniaceae, and finds that they exhibit 

 certain peculiarities which confirm the classification based upon the 

 morphology of the fruit and flower, and even in some cases are sufficient 

 of themselves for identification of a given plant. Moreover, in certain 

 instances, affinities are discovered which are not indicated by the 

 external morphology — e.g. the anatomy of Monsonia indicates a closer 

 relationship between that genus and Pelargonium than between it and 

 Erodium. The present paper gives strong support to the opinion that 

 classification should be based not merely upon external morphology, but 

 also upon the characters of the internal structure. 



Reproductive. 



Embryology of Gnetum.f — J. M. Coulter has studied the embryo- 

 sac and embryo of Gnetum gnemon with the following results. The 

 " antipodal tissue " proves to be nutritive tissue formed from the 

 nucellus below the embryo-sac. Embryo-formation starts with the 

 elongation of the fertilised egg, accompanied by free nuclear divisions 

 and wall-formation, which continues until a multicellular embryo is 

 formed. The endosperm encroaches irregularly upon the nuclear beak. 

 There are 12-24 chromosomes. The inner integument of the ovule 

 corresponds to the " inner fleshy layer " found among those Gymno- 

 sperms having only a single integument. There are two sets of vascular 

 strands, a condition which appears to be more primitive than that found 

 in the Coniferales and Ginkgoales. 



Male Gone and Gametophyte of Podocarpus.|— L. L. Burlingame 

 has examined the male cone and gametophyte of Podocarpus, and con- 

 firms the observations made by Coker, Jeffrey, and Chrysler, at the 

 same time showing that the phenomena observed by them are common 

 to other species. The two species examined — viz. P. totarra var. Hallii 

 and P. nivalis have two prothallial cells which may or may not divide. 

 The primary cells may give rise to as many as eight prothallial cells. 

 The prothallial cells show mitosis, and do not degenerate. Both stalk 

 and body-cells are found, but it is uncertain whether they produce male- 

 cells. There are 12 and 24 chromosomes. At the time of shedding, the 

 pollen-grain contains a variable number of cells, or free nuclei. The 

 author regards Pinus and Podocarpus as derived from a common 

 ancestral stock, assuming that in one case the prothallial complex has 

 been retained, while in the other case it has been lost. 



Structure of the Pistil, Ovule, Fruit, and Seed of Acanthaceae.§ 

 Ph. van Tieghem records the results of his investigation on this family. 

 In the species of Thunbergia examined, a vascular bundle ascends the 

 septum between the cells comprising the ovary, and these trifurcate, the 

 middle branch running up the style, while the lateral ones curve out- 

 wards and penetrate slightly into the ovule, where they stop without 

 branching. The single coat of the ovule is very thick, and the micro- 



* Comptes Eendus, cxlvii. (1908) pp. 382-4. 



f Bot. Gaz., xlvi. (1908) pp. 43-9 (1 pi.). 



j Tom. cit., pp. 161-75 (2 pis. and 9 figs.). 



§ Ann. Sci. Nat. ser. 9, vii. (1908) pp. 1-24. 



