270 SUMMARY OF CURRENT RESEARCHES RELATING TO 



flowering of the three lower members of the raceme. Their locality, 

 however, is marked by small riugs, slightly raised above the flat 

 surface formed by the end of the axis, and arranged spirally. While 

 the flowers of the lower raceme are in blossom, the first two or three 

 of these rings are exuding a kind of honey ; only one or twc^, however, 

 eeem to yield it at the same time. The honey flows freely, and when 

 removed is replaced in less than two or three minutes. 



These glands being extra-floral seem to take no part in cross- 

 fertilization, but they arc abundantly visited by ants. The plants 

 are free from insects before the period of honey secretion as well as 

 afterwards, whilst any attempting to get at the flowers during their 

 period of blossoming would be eftectually "crawled over" by the ants. 

 The ends of the panicle with the raceme belonging to them never 

 mature ; a short time before flowering they fall oft' at a clean-cut joint. 

 The presence of bees is necessary to ensure fertilization. 



j3. Physiologry.* 



Fecundation of Ovules in Angiosperms.f — J. Kruttschnitt further 

 developes his novel view that the pollen-tubes as they are found on 

 the stigma lose their separate existence, and discharge their contents 

 amongst the papilla> of the stigma which may be considered the 

 aggregate head of the fibrillfe of the conducting tissue which is found 

 in the stylo and in the various parts of the ovary, impregnating thus 

 the whole ovary, as an entirety, with the substance of the pollen which 

 has been absorbed by the papillse of the stigma. He considers that 

 the existence of the nucleus in the pollen-grains is problematic, and 

 its fusion with the oosphero in the embryo-sac not an observed or 

 demonstrable fact. The current view of the fertilization of the 

 plant ovule by " pollen-tubes " should be discarded, as it seems, he 

 thinks, to have been wrongly moulded on the fecundation of the 

 animal ovum. 



N. L. Britton combats J these views, and quotes a long list of 

 authorities in support of the accepted theory of fertilization, exhibit- 

 ing a section of Monotropa unijlora with the pollen-tube actually in 

 contact with the embryo-sac. 



Embryo of Cycade8e.§ — M. Treub supplies a gap in our know- 

 ledge of the development of the embryo of Cycas circinalis. The 

 corpuscules of this species have, as previously stated by Warming, only 

 two neck-eells, and Treub now shows that there is never any canal- 

 cell. The nucleus always occupies the same position, at the summit 

 of the central cell, close to the neck. If ovules recently fertilized 

 are treated with staining reagents, a crowd of small nuclei is seen in 

 the protoplasm, proceeding from the fertilized nucleus of the oosphere. 



* This subdivision contains (I) Reproduction (including the formation of the 

 Embryo and accompanying processes) ; (2) Germination ; (3) Growth ; (4) Respira- 

 tion ; (5) Movemeut ; and (6) Chemical processes (including Fermentation). 



t Proc. Amer. Soc. Micr. 7th Ann. Meeting, 1884, pp. 93-8. 



t Journ. New York Micr. Soc, i. (1885) pp. 7-lG, 20-1. 



§ Ann. Jard. Bot. Buitenzorg, iv. (1884) pp. 1-11 (2 pis.). See Bull. Soc. 

 Bot. France, xxxi. (1884) Rev. Bibl., p. 78. 



