PRAEFLORATION 



50 



ill classification in such families as Passifloraceae (Fij?. 110, a), Asclc- 

 ])iadaccac, and AiiKiri/llidaccac (Fif?. 117, a). A ring of intruded folds 

 at the throat (Fijj;. 119) is often, jjcrliaps incorrectly, called a crown. 

 It is sometimes very difficult to deterniine 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 Passi/lom which have no corolla, the attachment 

 is to the calvx onlv. 



//a 



Fig. IIG. T,i>nKitutlinal section, throviKli flower of Passiflora oxliihiting orown at a. 117. Flower of 

 Narcissus exliibiting a. large crown at a. US. Flower of Myoyotis. 11',). The same opened to sliow 

 folds in throat. 



Praefioration. — The arrangement of the ])arts of the perigone in the 

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

 tinguishing families, sub-families and genera, and has been the subject 

 of elaborate classification. The demands of pharmacognosy, however, 

 call for attention to only the princii)al types of Praefioration or Aesti- 

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

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

 to enclose the i)U(l, in which case ()])en s])accs must be left between 

 their margins {Rr.srdd) or the summit must be left uncovered (the calyx 

 in P^ig. 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. 12;), the calyx); 

 or {'.]) it must be excessive, in which case the excess may be dis])()sed 

 of in one of several ways. In one, the parts, after nuH-ting s(iuarely, 

 ar<' uniformly turned straight outward (Fig. 121), the form being 

 called Valvate Reduplicate. In another, they are turned straight 

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



