LARCH AND SPRUCE FIR CANKER. 35 



6. Anderson, A. P., Bull. Torrey Bot. Club, v. 29, p. 23 



(1902). 



7. Wagner, G., Zeitschr. Pfianzenkr., vi. p. 321 (1891). 



8. Somerville, W., Report on the Inquiry conducted by the 



Society into the Disease of the Larch, Trans. Engl. 

 Arbor. Soc, ii. p. 363 (1893-94). 



Description of the Figures. 

 Plate I. 



Fig. 1. Portion of stem of a young larch, showing a small 

 canker wound with ascophores or cups of Dasyscypha calycina; 

 natural size. (The result of artificial inoculation.) 



Fig. 2. A small but characteristic canker, with ascophores and 

 conidia-pustules of D. calycina ; natural size. 



Fig. 3. Ascophores and conidia-pustules of D. calycina; x 35. 



Fig. 4. Ascophores and conidisi-Tpustidesoi Dasyscypha resinaria; 

 x35. 



Fig. 5. Portion of a larch branch showing the white flocculent 

 tuft with a central drop of sap, which is constantly located near 

 to a "foundress'' aphis when with her eggs; x 5. 



Plate TI. 



Fig. 1. Section through an ascophore of Dasyscypha calycina; 

 x40. 



Fig. 2. Asci containing spores, also paraphyses, of D. calycina; 

 x400. 



Fig. 3. Section through an ascophore of D. calycina, showing 

 the mycelium of the fungus permeating and rupturing the bark 

 and cortex; x 400. 



Fig. 4. Section through a conidial-pustule of D. calycina; 

 x50. 



Fig. 5. Conidiophores and conidia of D. calycina; x 1200. 



Fig. 6. Conidia of D. calycina germinating in contact with a 

 thin section of larch bark in a hanging drop; x 1200. 



Fig. 7. Ascophores of D. calycina germinating in contact with 

 a thin section of larch bark in a hanging drop; x 400. 



Fig. 8. A single spoi-e of D. calycina germinating — the germ- 

 tube has penetrated the wall of the cell through a bordered pit; 

 x400. 



