1028 SUMMARY OF CURRENT RESEARCHES RELATING TO 



nucleus of the sperm- cell with the nucleus of the germ-cell, and as 

 being therefore of the nature of a process of nutrition. The course 

 of this union and the part taken in it by each constituent portion of 

 the nucleus is described in detail. The elements of the nuclei which 

 are not morphologically differentiated actually coalesce ; the nuclear 

 threads, on the contrary, of the two nuclei, do not coalesce, but simply 

 lay themselves in apposition one to another, and actually coalesce in 

 the daughter-nucleus only after the complete division of the germinal 

 nucleus. The segments then unite by their ends into a single thread, 

 which consists, therefore, half of segments derived from the father 

 and half of segments derived from the mother, and hence, in inverse 

 ratio, of portions derived from their more remote ancestors. This is, 

 according to Strasburger, the morphological explanation of the 

 inheritance of characters by descent. No morphological facts support 

 the hypothesis of a difference in function of the two portions of the 

 nucleus in conjugation ; there are no special male or female elements 

 which unite in the process. The influences of the male or female 

 parent on the offspring are the result of special characteristics 

 inherited by them from their ancestors. 



Hybridization and Cross-breeding of Plants.* — Dr. E. L. Sturt- 

 evant details his observations on crossed beans, maize, barley, peppers, 

 tomatoes, squash, lettuce, and peas, from the results of which he 

 concludes that in our domesticated vegetables cross-fertilization shows 

 its effects at once in the reproduction of the form-species and 

 varieties which are involved in the parentage of the crossed seed, 

 and that when "pure seed" is crossed, intermediate forms rarely 

 occur, but the original parents in variable proportions. 



Fertilization of the Wild Onion, f — Mr. A. E. Foerste describes 

 the fertilization of the (American) wild onion (Allium cernuum). The 

 flowers are arranged in dense umbels, and there are six stamens, which 

 arrive at maturity one after the other, the outer row developing first. 

 The style remains short, maturing after the anthers have burst. The 

 last stamen has shed its pollen before the stigma matures. The sta- 

 mens composing the outer row are partly enfolded by the inner 

 perianth-whorl, to which they are attached at their base. This tube 

 serves as a guide to the nectary, which lies just in front of the base 

 of the inner perianth-whorl. The nectary itself consists of three 

 organs placed so as to cover the ovary, being adnate to it, and bilobed 

 above in such a manner that the contiguous lobes approach each other, 

 and serve as a cover to the three nectary glands just beneath their 

 place of meeting. The lobes afterwards appear as six teeth cresting 

 the maturing ovary. Cross-fertilization is necessary in these plants, 

 and is effected by bees of various sizes. Self-fertilization is apparently 

 impossible. 



Fertilization in Campanula americana.J — Prof. Charles E. Barnes 

 finds that in this strongly proterandrous species, the pollen is scraped 



* Amer. Natural., xix. (1885) pp. 1040-4. See also p. 995. 



t Ibid., pp. 601-2 (4 figs.). 



i 13ot. Gazette, x. (1885) pp. 349-54 (1 pi.). See also infra, p. 1085. 



