THE FLOWER. 49 



60. The arrangement of the sepals and petals in the 

 flower-bud, or aestivation (Lat. cestas, summer), may best be 



,«>^, X— v\ /^-~Vv ®®®" "^ transverse sections of the 

 f vai-\f C0J2J I >m. \ bud when it is about ready to ex- 

 \^ ^/ V-,-'''' >>>5_^ pand. If the pieces do not over- 

 112 113 114 lap each other, but simply meet 



edge to edge, the sestivation is valvate (Fig. 112). Exam- 

 ples are furnished by the calyx of the Basswood and the 

 Mallow, and the corolla of Grape and Virginia Creeper. 

 In the valvate calyx, or corolla, if the edges turn inwards, 

 it is said to be induplicate ; if outwards, it is said to be 

 reduplicate. In the corolla of the Potato is an example 

 of the former ; and in the sepals of the Althea of the latter. 

 In case the parts overlap each other (as in the corolla of 

 Mallows), so that one edge of eac'h is covered, and the other 

 not, the aestivation is convolute (Fig. 113). When the 

 overlapping is such that some pieces are wholly inside and 

 others wholly outside, like the shingles on a roof (as in the 

 corolla of the Basswood), the aestivation is imbricate 

 (Lat. imbrex, tile; Fig. 114). 



61. The stamens consist of two parts (Fig. 121), namely, 

 the filament (Lat. filum, thread), or 

 slender stem ; and the anther, or en- 

 larged upper end. That portion of the 

 filament between the anther lobes is 

 called the connective. The filament is 

 not an essential part, and when wanting, 

 the anther is sessile. When the fila- 

 ments are united into a tube surrounding 

 the pistil, as in the Mallow (Fig. 115), they are said to be 



Figs. 112-114. Diagrams illusti-ating estivation : 112. Valvate ; 113. Convolute ; 

 114 Imbricate. Fig. 115. Mooadelphous stamens (y?/. mon.) in Mallow. 



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