251 SUMMARY OF CURRENT RESEARCHES RELATING TO 



From the point of view of their chemical composition, the author 

 classifies the odours of flowers under the following four heads, viz, : — 

 (1) indoloids (Stapelia, Bafflesia, AristolocMa, Aroidese) ; (2) aminoids 

 (Cratsegus, Pyrus, PacJiysandra, Sanguinaria, Ailanthus, Castanea) ; 

 (3) terpenoids {Lavandula, Dictamnus) ; (4) benzoids (Caryophyllus, 

 Dianihus, Hyacinthus, Asperula, Syfinga, Bohinia, Viola, Orchidese). 



B. CRYPTOGAMIA. 



Cryptogamia Vascularia. 



Doubling of the Endosperm in Vascular Cryptogams.* — Accord- 

 ing to M. P. Van Tieghem polystelic stems or leaves, with double 

 endoderm, exhibit, according to the diameter of the vascular bundles, 

 sometimes a pericycle in all of them, as in the single bundle in the 

 stems of Hymenopliyllum and the stolons of Nephrolepis, sometimes an 

 absence of pericycle in all of them, as in the single bundle of the stem 

 of Azolla, sometimes both arrangements. The doubling of the endoderm 

 occurs in many species of Polypodium ; and the bundles may be sur- 

 rounded by a pericycle, or this may be entirely wanting ; and these two 

 forms may occur in the same stem, the large bundles being provided 

 with a pericycle, whilst the smaller ones are without one. 



Systematic Position of the Rhizocarpese.f — From an investigation 

 of the structure of the prothallium in Marsilea and Pilularia, Dr. D. H. 

 Campbell has come to the conclusion that the family of Ehizocarpese, as 

 now constituted, consists of two groups, which represent the last terms 

 of two distinct series of forms. Of these the Marsileaceee are in all 

 probability derived from forms closely allied to living Polypodiaceae. 

 The exact position of the Salviniacese must remain for the present in 

 doubt, but they certainly should be removed from their present close 

 proximity to the Marsileaceae. 



Germination of Marsilia segyptiaca.ij: — Dr. D. H. Campbell has 

 followed out the germination of both microspores and megaspores of 

 this species. The microspore divides first of all into a larger and a 

 smaller cell, the latter of which is the vegetative portion of the prothal- 

 lium, and undergoes no further division. As in Pilularia and the 

 Polypodiacese, the former is the mother-cell of the antherid, and divides 

 further into the mother-cells of the antherozoids. The antherozoids 

 themselves resemble those of other species of the genus. In the 

 development of the archegone in the female prothallium there is no 

 production of " primordial cells " ; septa are formed at all stages of the 

 division. Only a single canal-cell could be detected with certainty, and 

 that was very short. 



Development of Pilularia.§ — Dr. D. H. Campbell has very care- 

 fully examined the structure and development of the male and female 

 prothallium and of the embryo of Pilularia glohulifera. He has em- 

 ployed, and strongly recommends for similar investigations, the process 

 of paraf&n-imbedding and cutting with a microtome. 



In the microspore the vegetative portion is more considerable than 



* Morot's Journ. de Bot., ii. (1888) pp. 404-6. 



t Bull. Torrey Bot. Club, xv. (1888) pp. 258-62. 



X Ber. Deutscli. Bot. Gesell., vi. (1888) pp. 840-5 (1 pi. and 1 fig.). 



§ Ann. of Bot., ii. (1888) pi». 233-64 (3 i^Is.). 



