CHAP. II. CALYX. 137 



any lateral rupture of its cap, as in Eucalyptus ; and calyp- 

 trate^ if at the period of falling it bursts on one side, as in 

 Eschscholtzia. In the former of these two cases, the cohesion 

 between the sepals is complete and never destroyed ; in the 

 latter, two of the sepals separate, the cohesion between the 

 remainder continuing complete. 



The calyx of Compositae is so very different in appearance 

 from the calyx of other plants, that it is known by the par- 

 ticular name oi pappus. It usually consists of hair-like pro- 

 cesses proceeding from the apex of the ovary, in which case it 

 is said to he pilose : if those hairs are themselves divided, it is 

 plumose ; if they are very unusually stiff", it is setose, in which 

 case the setae are often reduced in number to two, oi" even 

 one ; if the divisions of the pappus are broad and membranous, 

 it is said to be paleaceous : finally, it is sometimes reduced to 

 a mere rim : in which case it is said either to be marginate, 

 or to be none — to have no existence. If the pappus is in 

 two rows, which it occasionally is, the inner circle only is to 

 be understood as calyx : the exterior must then be accounted 

 bracts or paleae of the receptacle confluent witii the ovary. 



In such cases as those above mentioned, where the calyx is alto- 

 gether obsolete, the definition of that organ, as the most exter- 

 nal of the floral envelopes, appears to be destroyed ; but there 

 can be no doubt that it is present in the form of a membrane 

 adhering to the side of the ovary, although it is not visible to 

 our eyes. The same may be said of such plants as those 

 Acanthaceae {Introduction to the Nat. Syst., p. 2.33.), in which, 

 although the calyx is-sreduced to a mere ring, yet it does exist 

 in the shape of that ring. 



The Calyx being composed of leaves analogous to those of 

 the stem, but reduced in size and altered in appearance,- it 

 will follow that it is subject to the same laws of developement 

 as stem-leaves ; and, as the latter, in all cases, originate imme- 

 diately from the axis, helow those that succeed them in the 

 order of developement, so the calyx must always have an 

 oritrin beneath those other oraans which succeed it in the 

 form of corolla, stamen, and pistil or ovary. Hence has arisen 

 the axiom in botany, that whatever the apparent station of the 

 calyx may be, it always derives its origin from below the 

 ovary : nevertheless, it is often said to be superior. 



