ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 473 



General. 



Triple Hybrids.* — H. de Vries has investigated hybridisation in 

 (Jjiothera. Triple hybrids were produced by crossing 0. strigosa, 

 0. Hookeri, and 0. biennis with 0. lata and 0. scintillans. Of these 

 triple hybrids, two are the same as the twins from the similar crosses 

 with 0. LamarcMana, while the third resembles the mother, but in some 

 particulars is intermediate between its parents. It seems probable that 

 the splitting up of the offspring of the crosses should result in the 

 formation of quadruple hybrids. 



Pollination of Dendrobium.f — A. F. G. Kerr has investigated the 

 mode of pollination in various species of DendroUum. In D. Dal- 

 housieanum, which is described as being typical of all the species 

 examined, the bee {Lithurgm atratus) forces its way to the nectary and 

 its weight depresses the lip sufficiently to allow it to insert its proboscis 

 into the nectary. As it retreats it displaces both the rostellum and the 

 anther, owing to special jointed arrangements in these structures. The 

 tilting of the rostellum causes it to come into contact with the pollinia 

 and deposit on them a sticky secretion. The pollinia, being further 

 tilted, come into contact with the bee's thorax and adhere to it. As the 

 bee leaves the flower, the elasticity of the filament brings the empty 

 anther in front of the entrance to the passage, which it thus blocks. If 

 a bee now enters an unfertilised flower, the pollinia come into contact 

 with the stigma and adhere to it, but if the flower has been previously 

 entered, it merely pushes back the empty anther, and the latter then ad- 

 heres to the stigma and prevents the deposit of any more pollen. When 

 self -pollinated by artificial means, the flower soon withered away. 



Flora of the Malayan Peninsula.} — The tw T o last issued instalments 

 of this work, which was originated by the late Sir George King, and is 

 being continued by J. S. Gamble, contain accounts of the following 

 families of sympetalous Dicotyledons : — Apocynacese and Asclepiadacese, 

 elaborated by Gamble ; Loganiacese, by Sir Geo. King, excepting 

 Strychnos, which is by Gamble ; Acanthacese, by the late C. B. Clarke ; 

 and Labiata? and Plantaginaceaa, by Lt.-Col. Prain. 



CRYPTOGAMS. 



Pteridophyta. 

 (By A. Gepp, M.A. F.L.S.) 



Structure of Selaginella Lyallii.§ — H. Bruchmann gives an ac- 

 count of the vegetative organs of Selaginella Lyallii. In the summary 

 of his results the author says that the growing point consists of initial 

 cells, from which all the apical tissues arise, therein agreeing with 

 S. spinulosa and Lycopadium. The branching primarily appears to be 



* Bot. Gaz., xlvii. (1909) pp. 1-8. 



t Sci. Proc. Roy. Dublin Soc, xii. (1909) pp. 47-53 (2 pis.). 



\ Journ. Asiatic Soc. Bengal, lxxiv. pt. 2, extra Nos. (1907) pp. 387-728. 



§ Flora, xcix. (1909) pp. 436-64 (figs.). 



