CHAPTER VII. PREFLORATION OR AESTIVATION. 



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CHAPTER VII.— PREFLORATION OR ESTIVATION. 



By prefloration or aestivation is meant the arrangement of the 

 floral organs, particularly calyx and corolla, in the bud. Since 

 the parts of flowers are modified leaves, and flower-buds are 

 structurally similar to leaf-buds, it is not strange that most of 

 the terms explained under the head of prefoliation or vernation 

 are applicable also to the arrangement of the floral organs in 

 the bud. These terms need not again be defined, but a few addi- 

 tional forms will be described, all of them 

 relating to the arrangement of the organs 

 with reference to each other. 



i. The Valvate Prefloration. In this, 

 the margins of adjacent members are con- 

 tiguous merely, that is, do not at all overlap 

 in the bud. It is seen in its simplest form in 

 the calyx of the Basswood flower, a ground 

 plan of which is shown in Fig. 195. Of this 

 form there are three other modifications : the induplicate-valvate, 

 in which the edges of contiguous organs are bent inward, as in 



Fig. 196. 



Fig. 197. 



Fig. 198. 



Fig. 195. — GTOTiTtii plan of flower of common Basswood. 

 Fig. 196. — Diagram of induplicate-valvate prefloration. 

 Fig. 197. — Diagram of reduplicate-valvate prefloration. 

 Fig. 198. — Diagram of involute-valvate prefloration. 



Fig. 196 ; the reduplicate-valvate, in which the edges are bent 

 outward, as in Fig. 197 ; and the involute-valvate, in which the 

 edges are rolled inward, Fig. 198. 



2. The Imbricate Prefloration. Here the margins of adja- 

 cent parts overlap something like shingles on a roof. Of this, 



