94 
Air. Brown’s Observations on the 
that it is more analogous to the outer calyx of Scabiosn , which 
M. Cassini seems to consider different in its nature from both 
these parts. 
But the order of expansion in Lagasca , which is, though with 
some degree of irregularity, from centre to circumference, or 
that of the compound capitulum, seems to decide the question 
respecting the envelope of each flower, and to establish its iden¬ 
tity with involucrum : nor does this involucrum differ materially 
from that of Echinops, except in the reduced number and con¬ 
fluence of its component parts. 
The real structure of Ccesulia is perhaps less obvious. 
This genus, which was first published by Dr. Roxburgh*, is 
referred by him to Polygamia segregata ; the tubular envelope or 
involucrum of each floret being described as distinct from the in¬ 
cluded ovarium. 
Koenig, on the other hand, by whom the genus was discovered, 
and whose account of it is given in the same work, describes the 
partial involucrum of Roxburgh as the surface of the ovarium 
itself; its segments being, according to him, a pappus of two 
leaves. And lastly Willdenow, regarding this involucrum as merely 
paleee of the receptacle, refers the genus to Polygamia aequalis ; 
in which order it is continued, both in Persoon’s Synopsis, and in 
the second edition of Mr. Aiton’s Hortus Kewensis. 
This last view of the structure seems the most erroneous of any, 
and was probably adopted by 'Willdenow, in consequence of his 
having added to the genus a second species not really belonging 
to it, and which I shall have occasion to uotice in another part 
of my subject. 
An examination of the parts of fructification in different stages 
* In Corom. Plants, i. p. 64. t. 93. 
reconciles 
