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 
Eschseholtzia. 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 of 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, or 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 with 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 
Acanthaceag [Introduction to the Nat. Si/st., p. 233.), in which, 
although the calyx is reduced 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, below those that succeed them in the 
order of developement, so the calyx must always have an 
origin beneath those other organs 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. 
