80 THE FERTILISATION OF THE LARCH. 



mostly occur towards the outer extremity of a branch, and the 

 pedicel is twisted so that the cone stands erect. 



The male cones are much shorter than the female, more like a 

 capitulum. The outside is surrounded by brown, chaffy scales, 

 and the flat-topped central part is made up of shortened stamens. 

 These male cones cannot be said to be conspicuously coloured, 

 although when the pollen is ripe they have a yellow colour and 

 can be seen some considerable distance away. They are generally 

 sessile on the branch, and when they occur in the vicinity of a 

 female cone are turned away from it — generally looking earth- 

 wards. The anthers appear to discharge their pollen suddenly, 

 as is so commonly the case in anemophilous flowers. The larch 

 produces immense quantities of pollen — light, dry, and dusty in 

 character — but the pollen grains are not provided with wings as 

 is the case in Pinus sylvestris. 



In favour of wind-fertilisation, then, the following considerations 

 might be adduced :— 



i. The early season of flowering — while as yet insects are scarce. 



2. The appearance of the flowers before the leaves. 



3. The unisexual, monoecious condition more common among 



anemophilous than insect-fertilised flowers. 



4. The relative inconspicuousness of the male cones. 



5. The abundant pollen. 



6. Its dry, incoherent character and sudden discharge. 



7. Absence of honey and odour from both kinds of flower. 



8. No observation as to visits of insects. 



In favour of insect-fertilisation we have the following char- 

 acters : — 



1. The bright colour of bracts, which apparently disappears 



after fertilisation. 



2. The interference of the closely imbricated bracts with the 



access of wind to the ovules sheltering their stigmas. 



3. The large size of the pollen grains. 



4. The absence of wings on the pollen. (This, however, is 



inconclusive, as the pollen of the elm is also wingless.) 



5. The shortened axis of the male cone — the capitulum form 



of which might serve as a convenient alighting stage for 

 insects. 



