THE FLOKAL ENVELOPES CALYX. 



107 



become detached from the point where they appear to be inserted for 

 example, in Rosaceae, Umbelliferee, Cucurbitacese, Composite, &c. 



Polysepalous Calyx. In the polysepalous calyx, if the sepals 

 are alike and symmetrically arranged, the calyx is regular if some 

 of the sepals are larger than others (Helianthemum, Cheiranthus, 

 fig. 178) it becomes irregular ; and this is still more the case 

 when the sepals differ in form as well as size. Some of the most 

 remarkable irregular forms of polysepalous calyx occur accom- 

 panied by a petaloid condition, as in Aconitum (fig. 179) and Del- 

 phinium. 



The coloured calyces, both regular (Fuchsia) and irregular, may be 

 easily mistaken for corollas ; but they are known by their exterior posi- 

 tion, and in some cases by the existence of a more or less perfect corolline 

 circle within. 



Direction. The direction of sepals (whether distinct or partially co- 

 herent) is indicated by technical terms ; thus they may be erect, cvnni- 

 vent (the points turning in), divergent, or even re/icxed. 



Fig. 179. 



Fig. 178. 



Fig. 180. 



Fig. 178. Irregular polysepalous calyx of Cheiranthus. Two of the four sepals are dilated or 



"gibbous " at the base. 



Fig. 179. Irregular polysepalous coloured calyx of Aconitum Napellus, 

 Fig. 180. Kegular gamosepalous calyx of Silene injluta, 



Parts of a Gamosepalous Calyx. When the sepals are confluent 

 or not separated, the gamosepalous calyx (fig. 180) is usually de- 

 scribed as a whole. The part where the sepals are coherent or are 

 still inseparate is the tube ; the upper boundary of this is the throat 

 (faux) ; and the free or spreading portion constitutes the limb 

 composed of lobes or teeth with intervening sinuses when the upper 

 part of the sepals is more or less distinct ; entire when the sepals 

 are so completely confluent that the compound nature is not indi- 

 cated by any teeth or fissures at the free edge. 



It is necessary not to confound the receptacular tube with the calyx-tube 



