PHYSIOLOGY OF THE COROLLA. 207 



rosacea, rosaceous, spreading like a rose, Dryas, ?. 451. 

 papilionacea,f. 163, papilionaceous, irregi.ilar and spread- 

 ing, somewhat like a butterfly, Lathyi'us, t. 1108. 

 The various petals which compose such a flower arc 

 distinguished by appropriate names, as vexillum^j\ 

 164, standard, the large one at the back ; alcs^f. 165, 

 wings, the two side petals ; and carina, f. 166, the 

 keel, consisting of two petals, united or separate, em • 

 bracing the internal organs, yi 167. In Trifoliiim all 

 the petals are sometimes united into one at the lower 

 part. 

 incompleta, incomplete, when parts, which analogy would 

 lead us to expect, are deficient, as in Amorpha, a pa- 

 pilionaceous flower apparently, but consisting of the 

 vex'illum only ; or Rittera of Schreber,yi 168, a ro- 

 saceous one with a single lateral petal, seeming as if 

 four others had been stripped off". 

 It is remarkable that irregular flowers sometimes vary to 

 regular ones in the very same plant, as in B'g7ionia 

 radicans. Curt. Mag, ?. 485 ; and Antirrhinum Lina- 

 ria.f. 169, Engl. ^ot. t. 658 and 260. 

 Linnagus was of opinion that the Corolla originated 

 from the Liber or inner bark, as the Cdlyx from the out- 

 er, but this cannot be defended now the real physiolo^-y 

 of the bark is better imderstood. 



The whole use and physiology of the Corolla have not 

 yet been fully explained. As a protection to the tender 

 and important parts within, especially from wet, its use 

 in many cases is obvious, but by no means in ail. Lin- 

 n^us imagined i* to serve as wings, to waft the flower 

 up and dovv^n in the air, and so to promote the functions 



