24 BULLETIN UNIVERSITY OF MONTANA 



reticulation but old ones are remarkable for it. This is frequent through- 

 out the high peaks. 



Salix desertorum Rich. Gunsight Pass. 



Salix Candida Fluegge. Rost Lake and Schultze's cabin. 



Salix rostrata Rich. Common everywhere almost to the alpine. 



Salix macrocarpa Nutt. Bigfork, Swan Lake, McDonald peak, Hot 

 Springs, Monida, Lima. 



Salix pellita And. MacDougal peak, Swan Lake, Blackfoot and Sperry 

 Glaciers. Blankenship in his S'upp. Fl. Mont. p. 46 says that S. bella Piper 

 is a segregate from S. Sitchensis (namely is S. pellita), but this is an error, 

 it is a form of S. glaucops with two stamens. Cusick has at last solved 

 the relationship of S. pellita by finding that it always has one stamen and is 

 therefore the inland representative of S. Sitchensis as suggested in my Wil- 

 lows p. 25. 



Salix nigra has been reported from this region but all specimens so 

 referred are S. lasiandra. The same is true of S. amygdaloides. 



Salix lasiandra Benth. This is common around Flathead Lake, especially 

 on the shores, also St. Ignatius Mission, Ronan, Alta, McDonald Lake in the 

 Mission Mts. mostly the var. lancifolia. 



Populus trichocarpa T. & G. This seems to be the only narrow-leaved 

 Cottonwood west of the Atlantic slope. All forms so far reported as P. 

 balsamifera are this species. The only characters that seem to hold are the 

 3-valved pod and hairy surface, but even the latter apparently does not hold 

 In all cases. The species abound^ at low elevations everywhere. 



Populus deltoides Marsh. Flathead Delta, Thompson's Falls, Bonner's 

 Ferry, Idaho. Ours is the var. occidentalis with smaller leaves. 



Betula glandulosa Mx. In the Torrey Bulletin for August, 1909, Mr. B. T. 

 Butler, who was at Bigfork a few weeks in 1908 and a short time in 1909, 

 creates several species from this and B. micro phylla out of very small 

 amount of material and from very little field study, amounting to descrip- 

 tions drawn from single trees, none of which species are tenable. His segre- 

 gates from B. glandulosa are B. glandulifera Butler, B. Elrodiana Butler, B. 

 crenata Rydberg. To these might be added B. Hallii Howell. B. glandulosa 

 varies in size and leaves according to exposure and moisture where it grows. 

 It abounds at the cold lakes at low elevations and on up to the alpine mead- 

 ows on all the mountains from Alta in the far south to the Sperry Glacier 

 region. 



Betula microphylla Bunge. The typical form of this grows in Deer Lodge 

 valley. The common form is var. occidentalis (Hooker Fl. Am. 2 155 (1839) 

 as species). This has again been the subject of much unnecessary dissec- 

 tion such as B. fontinalis Sargent, B. Sandbergii Britton, B. Utahensis Brit- 

 ton, B. Piperi Britton. It is characterized by the chestnut-colored bark till 

 quite old, which does not peel up in thin flakes, the cambium layer not sep- 

 arating from the tree readily when cut, and by the tufted habit, growing in 

 clumps from a single root. In Utah and the drier regions it rarely reaches 

 20 feet high and is very slender, but in the more moist places in Montana, 

 especially along creeks it is often 30 or rarely 40 feet high and 6-8 inches 

 through. I have seen a few trees a foot thick in deep woods where the 

 bark peals up tardily and simulates forms of B. alba. It is almost never 

 seen except along creeks and at springs. The shape of the bracts amounts 

 to nothing. It is common in our region and east at least as far as Helena, 

 and south to southern Utah. 



Betula alba L. Mr. Butler takes up the paper birches and recognizes 

 every name ever applied to them but one as distinct species almost, such 

 as B. Alaskana Sargent, and B. papyrifera Mx. The paper birches are at 

 once recognized by growing singly from the root and forming large trees, 

 or at least are not tufted as in the other species. The cambium layer pops 

 off as soon as cut through carrying the rest of the bark with it. It grows 

 indifferently along creeks, lake shores and in dark woods in wet places. 



