3854 MR. G. MAW ON THE LIFE-HISTORY OF A CROCUS. 
The blade is generally about one eighth of an inch wide, the keel 
usually about one third of the width of the blade. "The blade is 
always more or less revolute, its margins approaching the margins 
of the keel, and the intervening spaces at the back of the blade are 
the lateral channels. These differ much in different species, and 
vary from being entirely open, as in the case of C. iridiflorus, to 
being closed by the margin of the blade meeting the margin of 
the keel. In the majority of species the lateral channels have a 
plain surface; and in some others they contain one, two, or three 
more or less prominent ribs, the presence or absence of which is 
a character for specifie distinction. 
The proper leaves are generally glabrous; but in certain spe- 
cies, e. g. those allied to C. sativus and to C. aureus, the margins 
of the keel and of the blade are ciliated. Of the several de- 
partures of the leaf-structure from the general type, the two 
vernal Spanish species C. carpetanus and C. nevadensis are the 
mostremarkable. In C. carpetanus the distinction between blade 
and keel is lost; the leaf is semicylindrical and the back fur- 
rowed with about sixteen alternating ribs and channels in lieu 
of a distinet keel and lateral channels. The South-Spanish 
C. nevadensis presents in its leaves a character intermediate 
between those of C. carpetanus and of the ordinary type, the back 
being ribbed and furrowed as in C. carpetanus, but also divided by 
slight lateral channels. 
In C. zonatus, C. vallicola, and C. Seharojani, three gpecies 
from Eastern Asia Minor, we have another aberrant type of leaf- 
structure. The keel being developed to the width, or nearly to the 
width, of the blade, and the white central band of the blade being 
almost lost, the back and front of the leaf look nearly alike. I 
shall have occasion further to notice these special leaf-structures 
when I refer to the presence of special secondary characters 
in relation to geographical distribution. 
The leaves of the great majority of the species appear with 
the flowers; but in zen autumnal species (C. iridiflorus, C. valli- 
cola, C. Scharojani, C. zonatus, C. karduchorum, C. nudiflorus, 
C. medius, C. peloponnesiacus, C. speciosus, and C. pulchellus) the 
leaves remain dormant within the sheathing-leaves till the ensuing 
spring. In the other fifty-nine species the leaves appear at the 
flowering-time ; in some they are well developed before the flowers 
appear, and in other species are only just visible beyond the sheath- 
ing-leaves. The leaves of every species continue to lengthen up to 
