746 SUMMARY OF CURRENT RESEARCHES RELATING TO 



the under side of the leaf : a coil of cells near the epidermis, with 

 certain hyphae which project from a stoma — the trichogynes. Spermatia 

 were seen in considerable numbers attached to the end cells of the 

 trichogynes, but no fusion was ever observed — the end cell of the tricho- 

 gyne was often seen to show signs of disorganization as soon as it 

 emerged from the stoma. It is suggested that these trichogynes, though 

 originally receptive, have now probably a respiratory function. The 

 development of the perithecia from the coil was observed and is fully 

 described, but it was not possible to trace the ascogonia. The only 

 nuclear fusion observed takes place in the ascus. Nuclear division 

 was followed in the ascus, and reduction was observed in the first 

 division. A second division followed rapidly, showing analogies with 

 meiosis rather than with brachymeiosis. The first formed four nuclei 

 rest for some time before undergoing division to form the eight spores 

 • — no reduction was visible at this stage, but the single reduction 

 observed is held to tally with the single fusion that took place in the 

 ascus. A general review of the nature of spermogonia and trichogynes 

 follows. 



Whitening of the Mountain Cedar, Sabina sabinoides.* — F. D. 

 Heald and F. A. Wolf describe the disease of the cedar, which is cha- 

 racterized by whitened areas on the trunks and branches of the affected 

 trees. The disease is so common that* the white areas have been con- 

 sidered a diagnostic character of this cedar. On the whitened areas are 

 found stromatic nodules, singly or in small groups, which vary in length 

 from 1 mm. to 2*25 mm. One to three perithecia are embedded in 

 each nodule, and their ostioles project as small papillae ; the asci contain 

 six or eight filamentous, multiseptate, very long spores, generally curved 

 or twisted. The fungus occurs most abundantly on the younger twigs 

 and on young trees ; it surrounds them and destroys the cambium 

 layer. The fungus has been named Cyanospora albicedrae g. et sp. n., 

 and has been placed in the family Ceratostomaceae. 



Mildew of Apples.j — J. Eriksson discusses chiefly the occurrence of 

 the mildew in Sweden, where it has only recently been detected, and 

 was probably imported from France. It is particularly harmful to 

 young plants, but it also attacks full-grown trees, and may be found on 

 pear trees, especially on the fruit. Eriksson gives a list of the varieties 

 attacked, and of those that proved immune. As preventive measures, 

 he recommends the collecting and burning of all shoots that are diseased, 

 and the spraying of the trees after the leaves have fallen, with Bordeaux 

 mixture, the spraying to be repeated in spring. 



American Gooseberry Mildew. — J. Eriksson J discusses the question 

 of immunity of different varieties of gooseberry bushes to the attack of 

 Spltserotheca mors-uvse. The American mountain gooseberry was not 

 quite immune, but proved very little liable to the disease, and he thinks 



* Mycologia, ii. (1910) pp. 205-12 (1 pi. and 3 figs.). 



t Prakt. Bl. Pflanzenb. Pflanzensch., 1909, pp. 73-7, 96-9. See also Zeitschr. 

 Pflanzenkr., xx. (1910) pp. 362-3. 



% Deutsche Obstbauz. (1909) 1 p. See also Zeitschr. Pflanzenkr., xx. (1910) 

 pp. 363-4. 





