XVI INTEODUCTION. 



usually called lecmes or segments) is one in wHch the sepals and petals are similar in form 

 and texture, and present apparently a single whorl. But if examined in the young bud, 

 one half of the parts will generally be found to be placed outside the other half, and 

 here wiU frequently be some slight difference in texture, size, and colour, indicating to 

 the close obserrer the presence of both calyx and corolla. Hence much discrepancy in 

 descriptive worts. Where one botanist describes a simple perianth of six segments, 

 another will speak of a double perianth of three sepals and three petals. 



99. The following terms and prefixes, expressive of the modifications of form and 

 arrangement of the corolla and its petals, are equally applicable to the calyx and its 

 sepals, and to the simple perianth and its segments. 



100. The Corolla is said to be monopetaloiis when the petals are united, either en- 

 tirely or at the base only, into a cup, tube, or ring ; polypetaloui when they are all 

 free fi'om the base. These expressions, established by a long usage, are not strictly 

 correct, for monopetalous (consisting of a single petal) should apply rather to a corolla 

 really reduced to a single petal, which would then be on one side of the axis ; and 

 poVypetalous is sometimes used more appropriately for a corolla with an indefinite 

 number of petals. Some modern botanists have therefore proposed the term grnno- 

 petalous for the corolla with united petals, and dialypetalous for that vrith free petals ; 

 but the old estabUshed expressions are still the most generally used. 



101. When the petals are partially united, the lower entire portion of the corolla is 

 called the tube, whatever be its shape, and the free portions of the petals are called the 

 teeth, lobes, or segments (39), according as they are short or long in proportion to the 

 whole length of the corolla. When the tube is excessively short, the petals appear at 

 first sight free, but then- slight union at the base must be carefully attended to, bebg 

 of miportance in classification. 



102. The .Sstivation of a corolla, is the arrangement of the petals, or of such portion 

 of them as is free, in the unexpanded bud. It is 



valvate, when they are strictly whorled in their whole length, their edges being 

 placed against each other without overlapping. If the edges are much inflexed, the 

 sestivation is at the same time indvplicate ; involute, if the margins are rolled inward j 

 redmphcate, if the margins project outwards into salient angles ; revolute, if the margins 

 are roUed outwards ; pUaate, if the petals are folded in longitudinal plaits. 

 • 1 ™*™"*«' ^l^en the whorl is more or less broken by some of the petals being out- 

 side the others, or by their overlapping each other at least at the top. Pive-petaled 

 imbnoate coroUas are qmncrnicially imbricate when one petal is outside, and an adioin- 

 mg one whoUy mside, the three others intermediate and overlapping on one side; 

 bilabiate, when two adjoining ones are inside or outside the three others. Imbricate 

 petals are described as crumpled {corrugate) when puckered irregularly in the bud. 



twisted, contorted, or convolute, when each petal overiaps an adioining one on one 

 side, and IB overlapped by the other adjoining one on the other side. Some botanists 

 include the tvnsted aistivatiou in the general term imbricates others carefully distin- 

 guish the one from the other. 



««i?v'J'^^^^^ ^Tl *l>e overlapping is so slight that the three ffistivations cannot 

 ^r^^^^^ fl,» ^'^^"^ one from the other j in a few others the estivation is variable, 



|:r: or'eX LTSal'oXf.™"'''' '' ^"^P^^" "^ '=°°^''"* ''''^''^' ^ ^P^^^"' '" 

 104. In general shape the Corolla is 



cyUnder"^"'"' "^^"^ ^^^ "'^"^^ °- ^^^ S^'"'^*""" P""-' °^ ** ^^ i" *!>« &"" of a tube or 



base.'^r n^tytS atTe^t ?t^' °' '°'" "'^ '"^''^ -* •>°--*«"y fr°- *•>« 



upper'^X^SaTded^i^t^^t^^t^Vr ^'^M"- P"' - oyl-^-cal and the 

 cylindrical part and the Wn^w^' ." ^ °T f"^ ''*'^<' °f ''«*« >« restricted- to the 

 th^e base orU.' Xf^r^T^ futTcSS ll^fo^; ^^o^ " '' '^^^^^ *" 



