256 SUMMARY OF CURRENT RESEARCHES RELATING TO 



give way suddenly at the point of contact with the lobes ; the capsule is 

 violently burst open, and the smooth round seeds thrown out to a distance 

 which may amount to four metres. The same mechanism occurs in other 

 6pecies of the genus. 



/8. Physiology.* 

 (1) Reproduction and Germination. 



Pollination of Serapias.f — Dr. L. Nicotra describes the mode of 

 pollination in two Italian species of Serapias, S. lingua and occultata. 

 In the latter species the structure of the flower is favourable to homogamy. 

 The pollen-masses become disintegrated into cubical msissulae which fall 

 in large numbers into the stigmatic cavity ; and pollen-tubes can be seen 

 in great quantities passing into the ovary. In S. lingua, on the other 

 hand, homogamy is almost impossible, and yet it appears to be left 

 almost entirely unvisited by insects. Pollen-masses are very rarely to 

 be seen on the stigma, and it is very rare for this species to produce 

 capsules and fertile seeds. 



Pollination in Zannichellia palustris. J — M. E. Roze thus describes 

 the floral arrangement of Zannichellia palustris : — The female flower is 

 composed of a membranous, cupuliform perigyne, inclosing two to six 

 pistils, at the base of which will be found the male flower consisting 

 of a single stamen. Tho filament of this stamen, which at first is almost 

 sessile, becomes longer than the pistils before flowering. When ripe, 

 the pollen escapes and falls into the water, and the funnel-shaped stigmas 

 immediately below the stamen receive those grains which touch any 

 point of their surface in their fall. It only remains now for the pollen- 

 grains to emit their tubes and penetrate to the embryo-sac ; but this has 

 not been actually observed by the author. 



Production of Sex and phenomena of Crossing. § — Dr. F. Nobbe 

 states, as the result of a number of experiments, that seeds of Leucojum 

 which germinate rapidly (in three to four days) produce chiefly or 

 exclusively plants with double flowers ; while those of the same species 

 which germinate slowly (in nine to ten days") produce chiefly single 

 fertile flowers. In hybridization he finds the hybrid to reproduce the 

 characters of the male ancestor in the inflorescence and in the relation- 

 ship of the double to the single flowers ; while the colour of the flower 

 is intermediate between that of the male and the female parent. 



Physiological Organography of Flowers. || — Herr K. F. Jordan 

 describes the structure, in reference to the mode of pollination, of a 

 number of flowers belonging to the following classes, viz. : — (1) Actino- 

 morphic honey-flowers ; (2) actinomorphic pollen-flowers (i. e. those in 

 which there is no nectary, but the pollen is devoured by the visiting 

 insect {Convallaria rnajalis); and (3) zygomorphic honey-flowers. In 

 all he finds a direct adaptation, in the position of the nectary, and in the 

 position and mode of dehiscence of the anthers, to pollination by insects, 



* This subdivision contains (1) Keproduction and Germination; (2) Nutrition 

 and Growth (including Movements of Fluids) ; (3) Irritability ; and (4) Chemical 

 Changes (including Kespiration and Fermentation). 



t Malpighia, i. (18S7) pp. 460-3. 



j Morot's Journ. Bot., i. (1887) pp. 296-9 (1 fig.). 



§ SB. Deutsch. Naturf. u. Aerzte, Wiesbaden, Sept. 20, 1887. See Bot. Centralbl., 

 xxxii. (1887) p. 253. || Ber. Deutsch. Bot. Gesell., v. (1887) pp. 327-44 (1 pi.). 



