. 
264 
reflexed. As the sporangia mature they simply push down the 
involucre, and almost, if not quite, cover and conceal it, but the 
edge of frond remains unchanged. In other words the involucre 
is distinctly two-valved, instead of being united with the edge of 
frond and therefore cup-shaped or campanulate; and I should be 
inclined to place it in the broad, two-lipped Aalantium group, in- 
stead of the cup-shaped Patania group where D. cicutaria belongs. 
Fertilization of Alnus incana and Salix discolor—{1) Alnus in- 
cana (L.) Willd. Anemophilous; self-fertilization is prevented by 
the amentiferous branches curving downward at the end, bringing 
the pistillate aments above the pendulous staminate. Usually 
monoecious, but the number and condition of the two kinds of 
aments varies greatly upon different plants. Many of the bushes 
have the staminate aments large and fully developed, a part of the 
branches bearing no other kind, the number of staminate ones to a 
branch then increases from 3 or 4 to 6,8 or 9. On the other hand, 
a part of the bushes have the staminate aments small and poorly 
developed, many branches bearing only the pistiliate kind, which 
are then more numerous than when the branch is monoecious. 
It is not rare for a large bush to produce only pistillate aments, 
which are then larger in size (about 1” longer) and a deeper 
brownish red. Young plants generally produce only staminate 
aments (from 4 to 7 branches are amentiferous) but this is never 
true of medium or large-sized bushes. The staminate aments are 
frequently injured by insect larvae. A branch two feet in length 
bore 297 aments of both kinds. The pistillate are much more 
numerous than the staminate ; of 663 aments examined on several 
branches of a single plant 471 were pistillate, 192 staminate. A 
staminate ament 2%’ long was composed of 31 scales, 77 flowers 
and 310 stamens. The parts of the flower are usually in fours, 
petals none, but occasionally a flower is five-parted, when five 
petal-like scales alternating with the sepals may be present. The 
pollen is abundant and easily set free by the wind. 
Visitor: During eight years I have never, except in one in- 
stance, seen this species of A/zus visited by insects. On April 6, 
1892, on a sunny hillside { observed a score or more of the honey- 
bee, Apzs mellifica 3, collecting pollen, Examination shower that oe 
the « poles teases ” were loaded with SS i 
