X INTRODUCTION TO BOTANY. 



lateral branches, successively developed, are usually forked 

 {dichotomous or trichotomous). Sometimes after the first forking 

 the branches are no longer diWdcd, but produce a succession of 

 pedicels on the upper side, forming apparently vmilateral 

 racemes ; but they difier from true racemes by the pedicels 

 spi-inging, not from the axil of the bract, but from a point 

 opposite its insertion or above or below it. This variety, called 

 a scorpioid cyme, is found in D>-o.-<v)-a, the Boragi)iecc, and many 

 other plants ; when young the branches are frequently rolled 

 back at the top like the tail of a scorpion, whence the name. 



63. Bracts are generally placed singly irnder each branch of the in- 

 florescence, and under each pedicel ; hracteoles are usually two, one on each 

 side, on the pedicel, or close under the flower, or on the calyx itself; but 

 bracts are also fr-equently scattered along the floral branches without 

 axillary pedicels. 



64. ^^^len several bracts are collected in a whorl, or are so close together 

 as to appear whorled, or are closely imbricated roimd the base of a head 

 of flowers or an umbel, they are collectively called an Involucre. The 

 bracts composing an involucre are variously teirmed, according to their 

 appearance, leaves, leaflets, bracts, or scales, when placed close beneath the 

 calyx, they form an ejiicalyx. Palece, or chafl", of the receptacle are the 

 inner scale-like bracts of Composites, grasses, and some other plants, 

 when of a thin, yet rigid substance, usually narrow, and pale or trans- 

 lucent. Glumes are the bracts of sedges and grasses. 



§ 9. The Flower. 



65. A flower is a terminal bud, enclosing the organs of reproduction by 

 seed. An unopened flower is called a flower-bud, or alahastrum ; and the 

 period between the opening of a flower and the commencement of withering 

 is called its anthesis. 



66. The parts of a flower or floral organs are — 1st, the perianth, con- 

 sisting either wholly of calyx, if in a single whorl ; or of calyx and corolla^ 

 if in a double whorl ; 2nd, the stamens, or fertilizing organs ; 3rd, the 

 pistil, which contains the ovules, or germs of the future seed. 



67. A complete flower is one in which the caljTj;, corolla, stamens, and 

 pistil are all present ; a perfect flower is one in which all these organs, or 

 such of them as are present, are capable of performing their several func- 

 tions. An incompltte flower is one in which some of the floral organs are 

 wanting ; and an imperfect flower one in which some organs are so altered 

 as to be incapable of performing their proper functions. Imperfect organs 

 are said to be suppressed, abortive, or rudimentary, if very much reduced in 

 size and almost obliterated. 



68. A flower is, 



dichlamydeous, when the perianth is in two distinct whorls. 

 monochlamydeous, when the perianth is in one whorl, or when 



caljTc and corolla are so consolidated as to appear in a single 



piece. 

 asepalous, when there is no calyx. 

 tqyetalous, when there is no corolla. 

 naked, when there is no perianth. 

 hermaphrodite, or bisexual, when both stamens and pistil are present 



and perfect. 

 male, or staminate, when stamens, but no pistil, or only an imperfect 



one, are present. 

 female, or pistillate, when there is a perfect instil, but no stamens, or 



only imperfect ones, present. 

 neuter, when both stamens and pistils are imperfect or absent. 



