AGRICULTURAL BOTANY. 435 



coast of South America, and 8. rnaglia, on the west side of the continent, have 

 had some part to play in its origin. 



Notes are given on the variation in form and color of some of the mutants of 

 8. maglia and S. commersonii. 



A recent example of m.utation in Solanum commersonii, L. Planchon 

 (Jour. Agr. Prat., n. ser., IS (WOO), Xo. J,7, pp. GD-'i, (JO.j).— The author states 

 that for a number of years he has been growing S. commersonii of the well- 

 known wild type, and that in 1908 a mutation was observed. Nothing out of 

 the ordinary was noted in the aerial parts of the plants, but when the tubers 

 were dug they showed some marked differences and were readily divided into 

 two groups, one closely resembling the common wild type, while the other was 

 considerably increased in size, of a yellowish color, with smooth skins, and 

 with some of the specimens weighing as much as 234 gm. 



These tubers were planted in 1909, and while some reverted to the an- 

 cestral type, others perpetuated the mutation, and on these the stems were 

 shorter, more erect, of a pale color ; the leaves were larger, of a greenish-yellow 

 color ; the flower characters were quite different from the wild type ; and the 

 tubers persisted in the form described above. In the wild type the rhizome 

 character was maintained, but this was completely lost in the new forms. The 

 general apijearauce of the tubers is said to have resembled very much those of 

 the connnon Early liose. 



The orig'in of the cultivated potato, L. Wittmack (Landw. Jahrb., 38 {1909), 

 Erganzungsb. 5, pp. 5ol-6()o, pLs. 2, figs. 16; Ber. Deiit. Bot. GeselL, 27 {1909), 

 Gen. Versamml. Heft 1, pp. 28-^2, figs. 6). — Studies have been made of the va- 

 rious species which have been claimed to be the original of the cultivated 

 potato. 



Upon the basis of flower and other characters the author divides the species 

 of Solanum into 4 groups, and many of the so-called species he considers syno- 

 nyms or hybrids of other well-differentiated species. He believes that S. 

 tuberosum is a good species and 8. etuberosum i)robably a hybrid. The va- 

 rieties of potatoes in common cultivation are believed to have been mostly de- 

 veloped from S. tuberosum. 8. maglia may have contributefl a little to their 

 origin, but 8. commersonii is thought to be in no way associated with the forms 

 now in cultivation. 



The ferments and latent life of resting seeds, Jean White (Proc. Roy. Sac. 

 [Lodon], 8cr. B, 81 {190D), A'o. B 550, pp. .Ji7-.jy/2).— The author has made a 

 study of seeds of cereals to determine . the effect of age on the germinating 

 power, the relation, if any, between the age of the seeds and the persistence of 

 their enzyms with reference to the correlation between germinating power and 

 enzyms, and the effect of extreme temperatures on germinative ability and 

 enzym reaction. The experiments were carried on with wheat, barely, oats, 

 maize, and rye of known age, from 6 months to 21 years. 



There was found to be a well-marked drop in the germinating power of 

 seeds after the fourth year, and in the case of wheat it descended more or less 

 irregularly, i-eaching zero in 11 to 17 years, according to the conditions of 

 storage. 



The resting seeds of cereals were all found to contain dlastatic, fibrin-digest- 

 ing, and ereptic ferments in appreciable quantities. These ferments retained 

 their activitj^ without appreciable change in dry stored seeds for 20 years or 

 more, or for a considerable time after the germinating power had been lost. 



No relation was noted between the vitality of seeds and the persistence of 

 enzyms in them, and the question as to whether germination can take place in 

 the absence of enzyms remains to be answered. 



