850 MR. G. MAW ON THE LIFE-HISTORY OF A CROCUS. 
vascular column, and is again reabsorbed at the completion of 
growth, leaving a small basal sear at the point of articulation. 
The process of annual corm-replacement is exhibited in Plate 
XXXIV. The new growth is, as it were, planted into the sub- 
stance of the old corm in a position which generally has no rela- 
tion to its axis of growth; the new eorm expands, absorbs the 
entire substance of its parent, and throws off a new set of tunics, 
which are added internally to the successive tunic-layers of many 
former generations. The tunies are homologous with the leaves; 
indeed, they are in part merely the expanded base of the leaves 
and sheathing-leaves, with a structure beautifully adapted for the 
protection of the annually expanding new corm. 
In the early stages of the new growth the base of the foliage com- 
pletely environs the incipient corm, and is articulated to its base 
within the mass of the old corm. As the new corm frees itself 
and expands, that part of the tunie which forms the bottom of 
the foliage disarticulates from the base of the corm in successive 
layers and slips upwards; this would leave the bottom of the 
corm exposed but for the existence of an organ I have termed 
the basal tunic. 1 look upon this as also homologous with the 
foliage; but its upward growth from the basal axis is so short 
that it adheres to the base of the corm, its short wiry rays elasp- 
ing the base of the main tunie asit slips upwards; and these, 
like our own upper and nether garments, collectively maintain 
the continuity of the clothing. 
Both the main tunic and the basal tunie present a great variety 
of adaptation. The vascular structure of the leaf is reproduced 
in the main tunie, which has a series of strong vertical coste OT 
fibres and intervening reticulations. A piece of net hung verti- 
cally will roughly represent the leaf-skeleton; and when drawn 
out laterally will as well represent a reticulated corm-tunic. 
This is in fact what really takes place, the expanding corm spread- 
ing out the vascular structure, which appears in a more condensed 
form in the leaf. The relation between the structure of the leaf 
and the corm-tunic is manifested by the fact that those species 
having little vascular tissue in the leaves have invariably a thin 
membranous tunie devoid of strong fibres. 
The limits of a single paper preclude my describing, with the 
detail that is necessary, the wonderful diversity of pattern and 
structure and the beautiful ornamentation found in the tunics 
of each species, exhibiting characters so well marked, that a mere 
