114 



STRUCTURAL BOTANY. 



do the petals of Magnolia ; and lastly, the Vexillary, when one 

 piece larger than the rest is folded over them, as in Pea (425). 



340. Plicate or folded aestivation occurs in tubular or mono- 

 pctalous flowers, and has many varieties, of which the most re- 

 markable is the supervolute, where the projecting folds all turn 

 obliquely in the same direction, as in the Morning-glory, Thorn- 

 apple (Datura). 



426 



DirujramxofJloicfrK (tin ftffn f/ crnns-section.*}. 426, Jeffersonia diphylla r>, ovary; *, stamens; d, inner 

 row of petals, activation triquetrous: t>, outer row of petals, aestivation contorted; c, sepals, aestivation 

 quincuncial. 427, Lily. 428, Strawberry. 429, Mustard. The pupil will designate modes of aestivation. 



It will be seen by the cuts that different modes of aastivation 

 may occur in the different whorls of the same flower. 



Review. 330. .What is the meaning of Metamorphosis ? Is the Flower a new principle ? 

 Whence is it ? 331. Two sources of proof. 332. What is said of the Poppy? 333. State 

 the first argument. What is proved by this ? Prove that the petals are leaves. Argu- 

 ment from the Water-lily From the Tulip-tree. 334. Define Teratology. State once 

 more the point to be proved. What are monstrous flowers ? How does the Rose become 

 double ? Change in the Double Cherry ? In Buttercups ? In fig. 417? 335. Meaning of 

 ^Estivation ? Why is the subject important ? Meaning of Vernation ? How to observe 

 them ? 336. Four general modes of ^Estivation. 337. Define the Valvate Its two va- 

 rieties. 338. Define the Contorted. 339. Define the Imbricated The Quincuncial Tri- 

 quetrousConvolute. How is it in the Pea ? Describe the aestivation of Convolvulus. 



CHAPTER XXV. 



INFLORESCENCE. 



341. Inflorescence is a term denoting the arrangement of the 

 flowers and their position upon the plant. 



All the buds of a plant are supposed to be originally of one and the same nature, look- 

 ing to the production of vegetative organs only. But at a certain period, a portion of the 

 buds of the living plant, by an unerring instinct little understood, are converted from 

 their ordinary intention into flower-buds, as stated and illustrated in the foregoing Chap- 

 ter. The flower-bud is incapable of extension. While the leaf-bud may unfold leaf after 

 leaf, and node after node, to an indefinite extent, the flower-bud blooms, dies, and arrests 

 forever the extension of the axis which bore it. 



342. In position and arrangement, flower-buds cannot differ 

 from leaf-buds, and both are settled by the same unerring law 



