OG THE FLOWER. é 
§8. OF ZSTIVATION. 
108. AisTIvATION (@stivus, of summer) is‘a term used by 
botanists, to denote the relative arrangement of the several 
organs of the flower while yet undeveloped in the bud. It is 
the same to the flower-bud as vERNaTION (vernus, of the spring) 
is to the leaf-bud. 
a. The different modes of xstivyation may be best observed in sections of the 
bud, made by cutting it in a horizontal direction. The most common Feene 
are the following. 
1. Valvate; applied to each other by the margins only; as the 
petals of the Umbellifere, the valves of a capsule, &e. 
2. Convolute ; when one is wholly rolled in another, as in the 
petals of the wall-flower. 
3. Quincuncial ; when the pieces are five in number, of which 
two are exterior, two interior, and the fifth covers the interior 
with one margin, and has its other margin covered by the ex- 
terior, as in Rosa. 
4. Contorted; each piece being oblique in figure, and over- 
lapping its neighbor by one margin, its other margin being, in 
hke manner, overlapped by that which stands next it, as 
the corolla of Apocynum. 
5. Alternative; when, the pieces being in two rows, the inner 
is covered by the outer in such a way that.each of the exterior 
rows overlaps half of two of the interior, as in the Liliacee. 
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FIG. 15.— Hstivation of the corolla; 1, Hydrangea; 2, Cheiranthus; 3, Rose (single) ; 
4, Oxalis; 5, Lilium; 6, Pisum; 7, Lysimachia; 8, Solanum; 9, calyx of the Rose. The 
last form, with 4 and 5, are also termed imbricate. 
