74 ARRANGEMENT OF FLORAL LEAVES 



Floral formulae and symbols. — Certain symbols and formulae 

 may be employed to denote briefly the morphology of a flower. 

 The signs and J, denote actinomorphic and zygomorphic 

 flowers respectively ; the direction of the arrow serves als6 to 

 show the plane of symmetry. A vertical arrow J, corresponds 

 with a median-zygomorphic, and a horizontal arrow -» with 

 a transverse-zygomorphic, flower. The signs (? , ? , $ , denote 

 respectively staminate, carpellary, and monoclinous flowers. 

 The capital letters K C (P), A and G represent the calyx, 

 corolla (perianth), androecium, and gynsecium. The number 

 placed immediately after each capital letter shows the number 

 of leaves in that particular whorl or spiral. If the gynaecium 

 be syncarpous, its number is enclosed in brackets, otherwise 

 the number is not in brackets ; if the ovary be inferior, a hori- 

 zontal line is drawn above its number, if it be superior the line 

 is placed below the number. The sign oo denotes that more 

 than twelve floral leaves are present, it therefore means 

 numerous. 



Floral for,mula of the $ flower of the Buttercup, 

 © K5 C5 Aoo Goo 



Floral formula of the $ flower of the Pea, 

 J, K5 C5 A5 + 5 Gl 



Floral formula of the cj flower of the Hazel, 

 © PO A42 GO 



Floral formula of the ? flower of the Hazel, 

 ® PO (?) AO G (2) 



SHAPE OF THE RECEPTACLE. 



Hypogjmous flowers (fig. 105). — In some simple flowers the 

 portion of the stem which bears the floral leaves — that is, the 

 receptacle — is distinctly elongated {e.g. Scotch Pine, figs. 63, 

 65 ; Buttercup, fig. 61). More frequently the internodes of the 

 receptacle are much shorter, though the flower-stalk terminates 

 in a rounded convex end {e.g. Wallflower, fig. 156; Poppy, fig. 

 153; Violet, fig. 158; Primrose, fig. 187). In such flowers 

 the carpels occupy not only the most central, but also the 

 highest, position; and petals and sepals are inserted at 

 successively lower levels. The flower is then said to be 

 hypogynous, and the gynaecium is superior. 



