ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 607 



has been decolorised by sulphurous acid, wbile fungi, or plants which 

 have been kept for a long time in the dark, or in an atmosphere free 

 from carbon dioxide, do not give this reaction. The distillate obtained 

 by boiling the liquid expressed from plants which have grown in sun- 

 light shows all the reactions of formaldehyd. 



Grafting the Potato on the Potato. * — Experiments made by 

 M. E. Laurent confirm the statements of Darwin and Vochting, rather 

 than those of earlier observers, that there was no mingling of characters 

 between graft and host when one variety was grafted on another very 

 similar one, graft and host each preserving its own individual characters. 



Green Hemi-parasites.f — Herr E. Heinricher's most recent observa- 

 tions on tLe parasitism, germination, and mode of growth of the Khinan- 

 theae relate chiefly to Bartsia alpina and Tozzia alpina. The seeds of 

 Bartsia do not require for their germination the neighbourhood of a 

 host-plant. Those of Tozzia, on the other baud, resemble in this respect 

 more closely the seeds of Orobanche and Lathrsea than those of the other 

 Rhinantheae. Their germination is dependent on the irritation resulting 

 from the vicinity of a host-plant. The seedling carries on a parasitic 

 existence for some years before it puts up a flowering branch, again in 

 this respect resembling Lathrsea. The author has succeeded also, for the 

 first time, in germinating the seeds of Thesium (alpinum). 



Germination of Orchideae.ij: — 'The miuute seeds of the Orchideae are 

 notoriously difficult to germinate. From the results of experiments made 

 chiefly on Neottia nidus-avis, M. N. Bernard believes the faculty of germi- 

 nation to be dependent on the presence of the mycorhiza or symbiotic 

 fungus which is invariably present in the root-hairs or cells of the root. 

 This fungus probably excretes a diastatic enzyme which assists in the 

 germination. The results are compared with those obtained with the 

 spores of Lycopodiaceae and Ophioglossaceae (see p. 611). 



Corallorhiza and its Mycorhiza.§— Mr. A. V. Jennings and Mr. H. 

 Hanna have studied the mycorhiza of Corallorhiza innata, which they 

 identify as Clitocybe infundibuliformis, and its effect on the host-plant. 

 They do not regard the relationship as true symbiosis, the fungus 

 appearing to be captured and utilised by the orchid without any corre- 

 sponding benefit to itself. The hypbae in the cells of the host-plant 

 are absorbed and made use of in forming food-materials for the host- 

 plant. Starch is most abundant in cells in which the hyphae are in a state 

 of decomposition. In no case could any enlargement of the hypbae be 

 detected in the neighbourhood of the cell-nucleus, nor was the nucleus 

 perceptibly enlarged. Tho hypbae of the fungus pass down the root- 

 hairs and through the outer layers of the root to the lower layers, where 

 the absorption takes place. 



Excretion of Water from Leaves. || — In the case of Phaseolus multi- 

 Jlorus, Dr. A. Nestl6r states that the drops of water are not exuded 



* Bull. Soc. R. Bot. Belgique, xxxix. (1900) pp. 9-16. 



t Ber. Deutsch. Bot. Ges., xvii. 1899 (1900) pp. 244-7. Cf. this Journal, 1899, 

 p. 175. \ Rev. Gen. de Bot. (Bonuier), xii. (1900) pp. 108-15. 



§ Sci. Proc. R. Dublin Soc., ix. (1899) pp. 1-12 (2 pis. and 8 figs.). 



|| S.B. K. Akad. Wiss. Wien, Nov. 3, 1899. See Oesterr. Bot. Zeitsehr., 1. (1900) 

 p. 26. 



