THE SPERMATOGENESIS OF Hysprip PEAS 541 
Vilcog, A. L’hybridation des Blés. La Nature, 30: 250. 1902. 
Vilmorin, H. L. de. (1) Cross Breeding. Gard. Chron, III. 14: 332. 1893; 
(2) On some hybrid poppies. Jour. Roy. Hort. Soc. 24: 203. 1900; (3) Per- 
petual strawberries. Jour. Roy. Hort. Soc. 22: 311. 1899; (4) Selection and 
its effects on cultivated plants. Exp. Sta. Rec. rr: 3. 1899. 
Vries, H. de. (1) Anwendung der Mutationslehre auf die Bastardierungsgesetze, 
Ber. Deuts, Bot. Gesells. 2t : 45. 1903; (2) Das Spaltungsgesetz der Bastarde. 
Ber, Deuts. Bot. Gesells. 18: 83. 1900; (3) Die Mutationstheorie. . Leipzig. 
1901 ; (4) Hybridising of monstrosities. Jour. Roy. Hort. Soc. 24: 69. 1900; 
(5) Sur la fécondation hybride de l’albumen. Compt. Rend. 129: 973. 1899; 
(6) Sur la fécondation hybride de l’endosperme chez le Mais. Rev. Gén. Bot. 
12: 129, 1900; (7) Sur la loi de disjoinction des hybrides. Compt. Rend. 
130: 845. 1900; (8) Sur les unités des caractéres spécifiques et leur application 
a l’étude des hybrides. Rev. Gén, Bot. 12: 257. 1900; (9) Ueber erbung- 
leiche Kreuzungen. Ber. Deuts. Bot. Gesells. 18: 435. 1900. 
Ward, C. W. Hybridizing and the introduction of new carnations. Am. Gard. 24: 
71. 1903. 
Waugh, F. A. Hybrid plums. Bull. Vermont Agric. Exp. Sta. 67: 3. 1898. 
Webber, H. J. (1) Complications in Citrus hybridization caused by polyembryony. 
Bot. Gaz. 29: 141. 1900; (2) Hybridism in Citrus. Gard. Chron. II. 27: 
186. 1900; (3) On a supposed immediate effect of pollen. Science, II. 4: 
498. 1896; (4) Work of the United States Department of Agriculture on plant 
hybridisation. Jour. Roy. Hort. Soc. 24: 128. 1900; (5) Xenia, or the im- 
mediate effect of pollen, in maize. Bull. Veg. Phys, & Path. U. S. Dept. Agric. 
24> 7,> E900. 
Webber, H. J. & Bessey, E. A. Progress of plant breeding in the United States, 
Yearb. Dept. Agric. 1899: 465. 1900. 
Weldon, W. F. R. (1) Mendel’s laws of alternative inheritance in peas. Biomet- 
rika, 1: 228. 1902; (2) On the ambiguity of Mendel’s categories. Biomet- 
rika, 2: 44. 1902; (3) Professor de Vries on the origin of species. Biomet- 
rika, 1: 365. 1902. 
Wilson, J. H. (1) Hybridization. Am. Gard. 20: 413. 1899; (2) Observation. 
on the fertilisation and hybridisation of some species of Al/buca. Bot. Jaarboeks 
3: 233. 1891; (3) The structure of certain new hybrids. Jour. Roy. Hort. Soc, 
24: 146. 1900. 
Witte, E. T. Hybrides des Bromeliacées cultivés en Europe. Leide. 1894. 
Wittmack, L. On the particular influence of each parent in hybrids. Jour. Roy. 
Hort. Soc. 24: 252. 1900. 
Wood, J. [Hybrid Newtown pippin apples.]. Am. Gard. 22: 134. 901. 
Woolson, G. A. A third New England station for Asplenium ebenoides. Rhodora, 
3: 248. Igor. 
Wunderlich, J. Beitrige zur anatomischen Charakteristik der Cirsium-Bastarde. Bot. 
Centialh, 65: 352. 1896. 
: Yasuda, A. On the artificial cross-fertilization between some garden varieties of 
Pharbitis hederacea L. Bot. Magaz. Tokyo, 11: (1). 1897. 
Explanation of Plates 
Nore, —A Zeiss microscope with a 2.00 mm. homogeneous oil-immersion objec- 
tive and a number 18 eye-piece were used, together with a camera lucida, in making aly 
of the sketches in plates 17 and 18, 
