ANGIOSPERMS. 



415 



by assuming ihe incomplete development of certain parts. Both whorls of the perianth 

 are developed in a petaloid manner, and like the whole flower are zygomorphic or 

 monosymmetrical (see below for this term). Of the typical androecium consisting 



FIG. 343. Floral diagram of Scrophularineae. The shaded leaves are the calyx-leaves right and left of them in A 

 and C bracteoles, beneath the flowers are their bracts, the aborted stamens are indicated by asterisks. A Verbascum 

 nigritm. B LinariaTJiilgaris ; the under lip is spurred, the dotted line shows the 'palate.' C Gratiola ojfficinalis\ the 

 two anterior stamens are developed as staminodes. D Veronica Chamaedrys with tetramerous calyx and corolla. 

 Lathraea. squamaria ; d scale of the disk. After Eichler, Bluthendiagramme, I. 



of two alternating whorls of three members each, only a single stamen, the anterior 

 stamen of the outer circle (Fig. 344 A), is fully developed in most of the Orchideae, the 

 others being abortive ; but indications of them sometimes appear in the young bud, as 

 in Calanthe veratrifolia according to Payer (Fig. 311), where at least the two obliquely 

 anterior stamens of the inner whorl (not the posterior one of the same whorl) are repre- 

 sented by two small protuberances which however soon disappear. In Cypripedium 

 on the other hand the place of the stamen which is 

 elsewhere fertile is occupied by a large staminode 

 in the front part of the flower (Fig. 284), while 

 the two obliquely anterior anthers of the inner 

 whorl are fully developed and fertile (Fig. 344 B). 

 In place of these fertile stamens of Cypripedium 

 two small staminodes are found in the Ophrydeae 

 beside the gynostemium (Fig. 354 D, st) ; in 

 Uropedium all three inner stamens are developed 

 (Doll), in Arundina pentandra as many as five 

 (Reichenbach fil.). The carpels which adhere to 

 the androecium to form the gynostemium are not 

 developed alike, but the difference is usually not perceptible in inferior ovaries, and is 

 therefore not indicated in the diagram. The beginner who desires to investigate these 

 points must observe that the long inferior ovary of most of the Orchideae suffers torsion 

 at the time of flowering which brings the posterior side of the flower round to the front ; 

 but transverse sections of older buds show plainly the true position of the flower with 

 reference to the parent-axis. 



Like the Orchideae, many though not all monocotyledonous flowers may be derived 

 from a type which is actually seen in the Liliaceae, and which represents a flower 

 consisting of five alternating whorls of three members each, the two outer of which 

 form the perianth, the two succeeding ones the androecium, and the innermost the 

 gynaeceum ; but the last may be represented by two whorls, and multiplication instead 

 of abortion sometimes takes place within the separate whorls and two members appear 

 in place of one, as in Biitomus (Fig. 299). 



FIG. 344. Floral diagram of Orchideae. A the 

 common form. B Cypripedium (see Fig. 283) ; the 

 dots denote stamens that are entirely wanting, the 

 shaded figures rudimentary stamens which are abortive 

 or developed as staminodes (see the text). 



