FLORAL DIAGRAMS AND FORMULA 



73 



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also well to include in the diagrams the inflorescence-axis, 

 and the bract or leaf in the axil of which the flower stands: 

 we at once see which is the 

 anterior and which the posterior 

 part of the flower. The diagram 

 will show where suppressions, etc., j^.. 

 have taken place (see figs. 192, 

 194, 219). 



.Estivation. — A cut made 

 across a flower-bud further reveals 

 the nature of the aestivation of 

 the calyx and corolla. The 

 sepals and petals, like leaves of 

 vegetative buds, may be arranged 

 in an open, a valvate (fig. 102), 

 or an imbricate (figs. 103, 104) 

 manner (see p. 128); especially 

 frequent is the two fifths 



aestivation of the calyx (fig. 104). The corolla is often 

 contorted (fig. 103; fig. 166) — that is, one edge of each petal 

 overlaps the edge of one adjoining petal, whilst its other margin 

 is overlapped by the margin of the petal on its other side. The 

 102 103 104 



Fig. loi. — Floral diagram of 

 Garden Pea. ■ 



CXJO 



Fig.s. 102-104. — Diagrams of eestivation. 



aestivation of the corolla of the Pansy (fig. 158) and Pea (fig. 

 1 01) is characteristic, and is described as descending-imbricate. 

 In the bud, the posterior petals (or petal) enfold with their edges 

 the lateral petals, and these in turn overlap the anterior petal 

 (or petals). When the aestivation of the corolla is precisely the 

 reverse, it is ascending-imbricate.* 



■* In a complete floral-diagram the eestivation of the calyx and corolla, 

 the insertion of the anthers, as well as the position of main axis and bract, 

 should be denoted ; but young beginners might omit these details. 



