58 THE PBRIGONE 



considerable variation in form and consistency, may or may not be 

 stipular in their nature. Marginal teeth extended into conspicuous 

 appendages have already been referred to. 



The Cauda or Tail. — Sometimes the apex is similarly prolonged into a 

 Cauda or Tail, an extremely exaggerated form of which is sometimes 

 seen (Fig. 115). 



The Awn. — An apex extended into an acute, stiff, slender point is 

 an Arista or Awn (Fig. 78, a). An awn sometimes emanates from the 

 producing organ at the back, instead of at the apex, and is then called 

 a Dorsal Awn. 



The Horn. — An awn-like body which is hollow is a Cornu or Horn 

 (Fig. 150, a). 



The Spur. — A horn-like appendage extending downward is called a 

 Calcar or Spur (Fig. 65). The spur may also be dorsal (Fig. 114). All 

 of the appendages noticed above may be found upon either calyx or 

 corolla. 



The Fornicate Corolla. — Sacs to the corolla are sometimes intruded, 

 as in Merlensia (Figs. 118 and 119), instead of extruded. The corolla 

 is then said to be Fornicate. Instead of sacs there may be longitudinal 

 folds, as in some species of Gentian. 



The Palate. — When a single large sac occludes the mouth of a bilabi- 

 ate corolla it is called a Palate (Fig. 94, d). 



Many appendages such as we have noticed are secretory in function 

 and they may even be glandular in form. Doubtless the various 

 secretions are characteristic, and might, in pharmacy, in exceptional 

 cases, be utilized for diagnostic purposes, but the attempt has never 

 yet been made. 



The Corona or Crown. — Lastly, we note what is perhaps the most 

 important, as it certainly is the most striking and interesting, of the 

 corolla or calyx appendages — namely, the Crown. The crown is an 

 outgrowth, more or less membranaceous, from the face of the perigone. 

 Its morphological nature is not understood or agreed upon, and is 

 probably not the same in all cases. It may be a mere abnormal product 

 of median chorisis, or it may be the homologue of the ligule of certain 

 leaves, hereafter to be considered (see h in Fig. 465, A), the latter being 

 regarded as a normal and morphologically distinct part. When the 

 crown develops from a petal with a distinct narrowed basal portion, 

 which may be assumed to correspond to the petiole of the formative 

 leaf, it usually develops from or near the point where this is joined 

 to the broader portion (Fig. 18). The crown becomes very important 



