1902.] NATURAL SCIENCES OF PHILADELPHIA. 503 



Peckiness. Eleventh Annual Report Missouri Botanical Garden, 



pp. 23-77. with six plates. 

 1900, PI. VON ScHRENK. Two DisBuses of the Red Cedar. U. S. Division 



of Vegetable Physiology and Pathology, Bulletin, 21, pp. 22, with 



seven plates. 

 1900, H. VON ScHiiENK. Some Diseases of New England Conifers. 



U. S. Division of Vegetable Physiology and Pathology, Bulletin, 25, 



pp. 56, with fifteen plates. 

 1900, H. VON ScHRENK. Fungous Diseases of Forest Trees. Year Book 



United States Department of Agriculture, 1900, pp. 199-210, Pis. 



XXI-XXV. 



1900, Shiiiai. Ueber der genetischen Zusammenhang zwischen Roes- 

 telia Koraensis P. Henn. und Gymnosporangium japonicum Sydow. 

 Zeitschrift fiir Pflanzenkrankheiten, X, pp. 1-5. 



1901, H. VON ScHRENK. A Discase of the Black Locust (Robinia 

 pseudacacia, L.). Twelfth Annual Report Missouri Botanical Gar- 

 den, pp. 21-31, with three plates. 



1901, Ward. Disease in Plants. London. 



1901, Atkinson. Studies of Some Shade Tree and Timber Destroying 

 Fungi. Cornell University Agricultural Experiment Station Bulle- 

 tin, 193, pp. 199-235, fig. 56. 



1902, Anderson. Dasyscypha resinaria causing Canker Growth on 

 Abies balsamea in Minnesota. Bulletin of the Torrey Botanical 

 Club, XXIX, pp. 23-34, with Plates 1 and 2. 



EXPLANATION OP PLATES XXII AND XXIII. 



Figs. 1, 2, 3, 4, 5. — Abnormal swellings on the white cedar (Cupressus 

 thi/oides') caused by m5^celium of fungus, Gymnosporangium biseptatum. 



Fig. 6. — Larger gnarled, diseased condition of the branches of white 

 cedar produced by O. Ellisii. 



Fig. 7. — Small swelling on twig of white cedar produced by the 

 mycelium of O. biseptatum. 



Fig. 8. — Straight witches' broom produced by the perennial mycelium 

 of a fungus, Gymnosporangium Kllisii. 



Fig. 9. — Normal tracheids of white cedar in transverse section. 



Fig. 10. — Cambium and adjacent cells from a normal stem. 



Fig. 11. — Normal resin canal from bark of white cedar, showing resin. 



Fig. 12. — Medullary ray cells and tracheids from a small abnormal 

 swelling, such as the photograph depicted in fig. 7. 



Fig. 13. — Diseased wood and excrescence on a young stem of white 

 cedar. 



Fig. 14.— Same section viewed entire. The depressed areas represent 

 spots where the cambium has been killed. 



Fig. 15.— Medullary ray cell from a longitudinal section, showing 

 appearance of brown contents. 



Fig. 16. — Tracheids filled with material under the stimulation of the 

 mycelium of G. biseptatum. 



Fig. 17. — Tracheids situated between two medullary ray cells, show- 

 ing those plugged with fungus gamboge. 



Fig, 18. — Cambial cells and outer wood tracheids, showing the 

 presence of hj'phse in cross-section. 



Fig. 19. — The same much enlarged. 



Fig. 22. — Tracheids and medullary ray cells from the wood of white 

 cedar, showing the course of the horizontal and longitudinal hypha;. 



Fig. 23. — Medullary ray cells, illustrating the manner in" which a 

 hypha penetrates the cell wall. 



