NEW DISEASE OF DOUGLAS FIK IN SCOTLAND. 1 49 



Explanation Of Plates IV. and V. 



All the photographs and figures refer to Phomopsis Pseudotsugae, n.sp., on 

 Pseudotsttga Douglasii. 



Photo i. Four-year-old tree with leading shoot killed. About \ nat. size. 

 Photo 2. Apical portion of dead leading shoot of a four-year-old tree ; the 



pyenidia can be seen on the stem and leaves. About % nat. size. 

 Photo 3. Four-year-old tree attacked near ground-level ; resin blisters on 



bark above and below constricted portion. About f nat. size. 

 Fig. 4. Portion of a young shoot showing pyenidia ; a, A-spores in the 



form of mucilaginous tendrils emerging from several pyenidia ; 



b, a single pyenidium from which a rounded mass of A-spores 



has just emerged ; c, a group of two pyenidia from each of 



which a rounded mass of A-spores has emerged ; d, a group 



of two empty pyenidia, each showing an ostiole (as a rounded 



black dot). x about 16 times. 

 Fig. 5. A pyenidium containing B-spores seen in longitudinal section 



(the spores are not shown) ; a, the layer of sporophores ; 



b, outermost layer of bark. x about 35 times. 

 FlG. 6. A-spores, some still attached to sporophores. x 720. 

 Fig. 7. B-spores, some still attached to sporophores. x 720. 



18. Notes on Jack Pines and Sitka Spruce. 



( With Plates.) 

 By James Kay, B.Sc.F. 



The three Jack pines are regionally distributed throughout 

 Canada and the United States, and cover large areas of poor 

 soils. This is due principally to their extreme hardiness, early 

 and large seed production, and ability to seed up burned-over 

 lands to the exclusion of more valuable species. 



The three forms are : — 



1. Eastern Jack Pine (Pinus banksiana), extending from 

 Nova Scotia to the Rocky Mountains, and the valley of the 

 M'Kenzie river, where it meets the lodgepole pine. 



2. Lodgepole Pine {Pinus contorta var. murrayana), 

 extending over the whole of British Columbia, from the Yukon 

 territory in the north and the eastern slopes of the Rocky 

 Mountains, and east to the Cypress Hills in Alberta. 



3. Scrub Pine (Pinus contorta), found on the coast (Pacific), 

 from the coast of Alaska to Northern California. It is 

 usually found in sphagnum-covered bogs and the margins 

 of deep wet swamps, but spreads inland and ascends the 



