No. 411.] NORTHERN APETALOUS FLOWERS. 201 
a handsome yellow. The thread-like stigmas of the pistillate 
are bright scarlet. In C. purpurea the leaves, husk, and pellicle 
of the kernel are purple. The hornbeam has the anthers pale 
yellow and the inner bark yields a yellow dye. In the genus 
Betula the flowers are greenish-yellow and the leaves are a pale 
yellow in spring and a bright yellow in autumn. The aments 
of Alnus are a reddish-brown, and the leaves turn to a dull dark 
brown. The styles, as a rule, in early flowering spring plants 
are crimson, a coloring which, by converting light rays into heat, 
favors the growth of the pollen tubes. In several instances I 
have seen the male flowers of Alnus incana visited by the honey- 
bee for pollen. Müller states that he has seen numerous honey- 
bees collecting pollen on the male flowers of the European 
species of hazel (Corylus avellana). 
In the Fagaceze, or beech family, there are no petals, but the 
calyx is present in both kinds of flowers. In the beech, one 
of our handsomest trees, the greenish-yellow calyx is bell- 
shaped, 5—8-cleft in the staminate, but 6-lobed in the pistillate 
flowers. The inflorescence is in small clusters. In the chest- 
nut (Castanea dentata) the flowers are exceedingly abundant 
and give a yellowish tinge to the whole tree. The staminate 
flowers may contain an abortive ovary and the pistillate five to 
twelve abortive stamens; the former are in aments, the latter 
clustered several in an involucre. The flowers of the oak are 
greenish, sometimes reddish, as well as the scales of the invo- 
lucre and the leaves in autumn. The species of Quercus are 
exceedingly variable. Of Q. robur there are twenty-eight varie- 
ties, while several other species have from eight to ten. No 
sharp line of demarcation is possible, as they grade into cach 
other by many intermediate forms. At the time of his revi- 
sion of the family De Candolle wrote, ** It is difficult to believe 
that above one-third of the actual species in botanical works 
will remain unchanged." The wood of the Fagacec is com- 
monly brown or reddish-brown, the inner bark of Quercus velu- 
tina (tinctoria) is orange and yields a yellow dye. 
It has been shown that the scales and perianth of the Amen- 
taceze present a wide range of coloring, including nearly every 
hue save blue. If the flowers were once entomophilous, as 
