'502 SUMMARY OF CURRENT RESEARCHES RELATING TO 



production of the endosperm. All the kernels grown by the writer in 

 which xenia was shown by changes in colour, were proved to be true 

 hybrids. It is not improbable that in some cases the second pollen- 

 nucleus enters the embryo-sac, but fails to unite with the two polar 

 nuclei. In such cases it may be able to form a spindle and to divide 

 separately, the unfecundatcd cmbryo-sac-nucleus formed by the union 

 of the two polar nuclei also dividing separately. If this occurs, there 

 would then be formed, in the protoplasm of the embryo-sac, nuclei of 

 two distinct characters, one group from the division of the embryo-sac- 

 nucleus, the other group from the division of the pollen-tube nucleus. 



Hybridisation.* — Mr. \V. M. Webb gives an interesting summary 

 of the more important results obtained in the papers read at the Con- 

 ference on Hybridisation and Cross-breeding held by the Eoyal Horti- 

 cultural Society. The following may be especially mentioned. 



In the genus Anthurium M. de la Devansaye says that the pollen, 

 to bo of value, must come from plants springing from a different batch 

 of seeds from that giving rise to the ovule-bearing individuals; that 

 pollen from allied geuera has a beneficial effect ; and that variations 

 which are not seen in the first or second generation may appear in the 

 third or fourth. 



An intermediate condition of external structure was brought out by 

 Dr. Wilson in hybrids of Passijlora, Albuca, Bibes, and Begonia. 



From experiments with cereals and Bromeliacere, Dr. Wittmack 

 concludes that the mother has more influence upon the habit, the father 

 more influence on the inflorescence, at least upon its colour. 



According to Herr Max Leichtlin, the female parent gives to the 

 offspring the form and shape of the flowers, also certain qualities ; the 

 male parent gives more or less of the colouring of the flowers, and if 

 it be richer and blooms more freely than the female, this property is 

 transmitted to the offspring ; artificially produced offspring give larger 

 flowers than either of their parents ; the more distant the habitats of 

 the species intended to hybridise, the more difficult it is for them to 

 be fertilised with each other's pollen ; the offspring becomes infertile 

 and delicate if the form of the flowers of their parents is widely dif- 

 ferent in shape and outline. 



Artificial Crossing of Pisuni sativum.! — Heir E. Tsehermak has 

 oxperimented on the artificial crossing of the garden pea, which is 

 entirely self-pollinated within the closed corolla, and is very rarely 

 visited by insects. His conclusions confirm those of Darwin, that the 

 number and weight of the seeds of this species are to no extent depen- 

 dent on self-pollination, or pollination between different flowers of the 

 same plant, between different individuals of the s.ime variety, or be- 

 tween different varieties. Double pollination of a pure variety by its 

 own pollen or by that of the same variety and by pollen of another 

 variety, or by pollen of two different varieties, is efficacious with regard 

 to both pollens ; the one kind of poljen does not in any way interfere 

 with the potency of the other kind. 



* Journ. R. Hoit. Soc, xxiv. (1900) pp. 1-318 (123 figs.). See Nature, lxii. 

 (1900) p. 174. 



f Bur. Deutsch. Bot. Ges., xviii. (1900) pp. 231-9. 



