88 THE LIFE-HISTORY OF A CROCUS. 



consisting of the expanded base of the leaves. The author illus- 

 trated this by means of two pieces of netting, one hung vertically 

 representing the vascular structure of a leaf, the other pulled out, 

 literally exactly resembling a reticulated corm-tunic. On the very 

 summit of the corm there are also small tunics or caps representing 

 the base of abortive leaves which have been arrested in their upward 

 development. The basal tunic is homologous with a condensed 

 whorl of leaves united together at their base, and attached to the 

 base of the corm. In the reticulated species it consists of a 

 coriaceous disc, surrounded by short wiry rays, which bend 

 upwards and inwards, and, by clasping the base of the main tunic, 

 maintain the continuity of the covering, as the main tunic slips 

 upwards concurrently with the corm expansion. In the annulate 

 species the basal tunic occurs in a still more condensed form, as a 

 series of coriaceous annuli bearing a margin of little teeth corre- 

 sponding with the longer rays of the reticulated species. The 

 author pointed out the great diversity of beautiful patterns in the 

 timic structure, and withal so well marked that a mere fi'agment 

 was often sufficient for the determination of a species. Every 

 gi-adation occurs between tunics consisting of thm membrane, thick 

 coriaceous coats, fine parallel fibre, and an infinite variety of reti- 

 culated structui-es. The most aberrant are the tunics of C. 

 Fleischeri and C. parviflorus, in which the fibres are arranged in 

 interwoven vertical plats or strands resembling the stranded 

 tunics of several eastern species of XijMum. All these divers 

 structui'es. are adaptations to maintain a continuous covering 

 during the alternate expansion and absorption of the corm. 



Of leaves there are two distinct sets, the outer whorl or 

 sheathing leaves, adapted to enclose the entire ascending axis, and 

 the inner whorl or proper leaves. In the majority of species the 

 leaves appear with the flowers, but in ten autumnal species they 

 remain dormant till the ensuing spring. A sheet of enlarged leaf- 

 sections exhibited the wonderful diversity of leaf- structure : nor- 

 mally there is a blade and a distinct keel of about a third of its 

 width, with intervening lateral channels ; in one Spanish species, 

 C. carpetanus, the distinction between the keel and blade is lost, 

 and the leaf is semi-cyhndrical, the back being sculptured into a 

 series of regular flutings exactly resembling those of a Corinthian 

 column ; in a second Si^anish s^Decies, C. nevadensis, a structm'e is 

 found intermediate in character between the ordinary type of leaf 

 and the leaf of C. carpetanus. In three eastern species, C. vallicola, 

 C. Scharojani, and C. zonatus, the leaves depart fi'om the usual 

 structure in the opposite direction, the keel being developed to 

 nearly the width of the blade. In some species the leaves are 

 ciliated, and in others glabrous, and the presence or absence of 

 more or less prominent ridges within the lateral channels was 

 stated to be of importance for specific distinction. The author laid 

 stress on the fact that special leaf-structm-e was more notably con- 

 nected with geographical distribution than with the natural affinity 

 of species. The scape, which in every species is either tetra- 

 quetrous or triquetrous, is generally about an inch or an inch and 



