374 



BRITISH FLOWERING PLANTS 



character of tlie bud is due to the leaves being on the 

 two -fifths .plan of arrangement. The centres of the 

 stipules correspond with the angles, wdiile the leaves lie 

 in the middle of the flat surfaces. Figs. 272-292 show 

 the succession of bud scales, of which, as will be seen, 

 there are some forty before the first leaf is produced. 

 For the form of the leaf, see ante, p. 362. 



The three genera Fagus, Castanea, and Quercus 

 have in the female flower three united carpels, forming 



Fig. 293. — Young female flower of 

 Oak enveloped by an involucre of 

 scales, s, from which protrude 

 the three stigmas. Much enlarged. 



Fig. 294. — The same, cut lengthwise. Two 

 of the ovary chambers have been opened 

 by the section, exposing one ovule in 

 each. 



a three -chambered ovary, with two ovules in each 

 chamber. The fruit is, however, one-seeded, as five of 

 the six ovules do not form a seed. These genera are 

 often placed in a separate order — Fagacese — from the 

 following four, in which the pistil contains only two 

 carpels, and which comprise the order Corylacese. 



The cup surrounding the base of the acorn is formed 

 from the union of a number of scales borne on the floral 

 axis below the flower (Figs. 293, 294). 



Betula (Birch) 



Flowers monoecious and protogynous. The pollen 

 is wind-borne. The male and female catkins are not 

 simple spikes, but compound inflorescences, each bract 

 on the main axis subtending a group of three flowers. 

 The fruits are surrounded by a scarious wing, and rest. 



