APETALA 187 
The leaves are opposite as in Beech or alternate 
asin Alder. The leaves may be entire and linear- 
lanceolate as in willows, with a crenate margin, or 
deeply lobed as in the Oak. 
The flowers are borne in catkins. The stamens are 
five to twenty in Cupuliferz, the pistillate flowers 
being sessile in an involucre of free or connate bracts. 
In Betulacez the stamens are distinct and four to 
twelve, there being fourin Alder. In Salicacez there 
are one, two, three or five, in Myricacez six to eight, 
which are monadelphous. In Cupuliferz the stami- 
nate flowers are in catkins, the calyx having five sepals 
or none, whereas it is made up of six teeth in the 
pistillate flowers. The fruit is indehiscent and bracts 
form a leathery case. There may be one style or 
none in Betulacez and two stigmas; the fruit is 
indehiscent without bracts, membranous, winged in 
Betula, not in Alder. In Salicaceze there are two 
short styles and two stigmas, and bracts enclose each 
flower. The catkins are erect at first in Populus, 
then drooping, in Salix always erect or slightly 
recurved. 
In Myricacez the fruit is a drupe with a waxy 
excretion. The ovary is sessile and there are two 
styles. 
Oak (Quercus Robur). 
The Oak is a true native of the British Isles, and 
is found in every county except in a few parts of 
Scotland. In the Highlands it is found at an altitude 
of 1350 ft. 
