PRAEFLORATION 



59 



in classification in such families as Passifloraceae (Fig. 116, a), Ascle- 

 •piadaceae, and Amaryllidaceae (Fig. 117, a). A ring of intruded folds 

 at the throat (Fig. 119) is often, perhaps incorrectly, called a crown. 

 It is sometimes very difficult to determine whether the crown is an 

 appendage of the corolla or of the androecium. Its adhesion is some- 

 times to the androecium and not to the corolla, and sometimes to both. 

 In some species of Passiflora which have no corolla, the attachment 

 is to the calyx only. 



Fig. 116. Longitudinal section, through flower of Passiflora exhibiting crown at a. 117. Flower of 

 Narcissus exhibiting a large crown at a. 118. Flower of Myosoiis. 119. The same opened to show 

 folds in throat. 



Praefloration. — The arrangement of the parts of the perigone in the 

 bud yields some of our most important diagnostic characters as dis- 

 tinguishing famihes, sub-famifies and genera, and has been the subject 

 of elaborate classification. The demands of pharmacognosy, however, 

 call for attention to only the principal types of Praefloration or Aesti- 

 vation. The three principal types depend upon the fact that the com- 

 bined breadth of all the parts of a perigone circle must (1) be insufficient 

 to enclose the bud, in which case open spaces must be left between 

 their margins (Reseda) or the summit must be left uncovered (the calyx 

 in Fig. 120), the form in either case being called Open; (2) it must be 

 exactly sufficient to enclose it, the edges then meeting exactly, with 

 nothing to spare and the form being called Valvate (Fig. 123, the calyx) ; 

 or (3) it must be excessive, in which case the excess may be disposed 

 of in one of several ways. In one, the parts, after meeting squarely, 

 are uniformly turned straight outward (Fig. 121), the form being 

 called Valvate Reduplicate. In another, they are turned straight 

 inward, the Valvate Induplicate form (Fig. 122). They may even be 



