548 



BOTANY 



PART II 



of unlimited growth. Flowers P2, A2 ; in dicliasia of tlii'ee, adherent to 

 the bract. Anthers deeply bifid (Fig. 519, 3, 4 ; Fig. 520). Female inflorescences 

 solitary, at the apex of small, short shoots of the current year. Flowers in 

 dicliasia of three in relation to each three-lobed scale ; the latter is composed 

 of the bract and the two adherent bracteoles. Fruits borne on pendulous 

 catkins ; winged. After the fruits are shed the scales of tlie catkin separate. 

 Cmyiiius Bctulus, the Hornbeam (Fig. 521), is an important forest-tree. The 

 inflorescences appear in spring, the male, from axillary buds of the previous 



year, either want leaves 

 or are accompanied by 

 one or two, the female are 

 usually terminal. The 

 bract of the male catkin 

 bears 4-10 stamens, bifid 

 to the base, but without 

 bracteoles or perigone. 

 Two female flowers in 

 relation to each bract ; 

 each flower with its 

 special bract and pair of 

 bracteoles. The three 

 latter unite to form a 





Fig. 519. — Betvla verrucosa. 1, Branch with terminal male catkins 

 anfl female catkins on small lateral branches. £', Female flower. 

 ,i, Male flower. U, Stamen. 5, A catkin iu fruit. C, Fruit. 

 (1 and .V, 3 uat. size ; 2-i and C, enlarged.) 



PiQ. 520. — Bet Ilia varrnmsa. 

 Diagrams from Fig. 510, 3 

 and 2. 6, bract; a ^, bract- 

 eoles. (After EicHLER.) 



three-lobed involucre which serves as an aid to distribution of the fruit by the 

 wind. Corylus avellana, the Hazel (Fig. 522), develops its inflorescences in the 

 preceding year. The male catkins are freely exposed during the winter, while 

 the female remain enclosed by the bud-scales, and only protrude tlieir long red 

 stigmas betM'een the scales at the actual time of flowering. The male flower 

 has no perianth but has a ])air of bracteoles which are adlierent to the bract, 

 as are the four deeply bifid stamens (Fig. 523). In the short female catkins 

 a two-flowered dichasium is present in the axil of each bract as in Carpmus ; 

 tlie fringed involucre also is derived from the coherent bracteoles and special bract 

 of each flower (Fig. 523). Corylvs tulnUosa from southern Euroi)e. 



Family 2. Cupuliferae. — Inflorescences in the leaf axils, as a 



