352 MR. 6. MAW ON THE LIFE-HISTORY OF À CROCUS. 
land 2. Some tunies are composed almost exclusively of mem- 
brane; others are strongly coriaceous, without much apparent 
fibre. The coriaceous and membranous tunics occasionally pre- 
sent a fibroid strueture without having true fibre; and, as in 
the case of Crocus aureus and C. serotinus, the strong membra- 
nous tunie is split up into flat, fibre-like, parallel divisions. 
Perhaps the most remarkable tunic-structure is presented in two 
eastern species, C. Fleischer? and C. parviflorus, in which the 
fibres are distinctly platted into parallel vertical strands. 
In the basal tunie we also find a great variety of pattern. It 
generally consists of a star-like structure of fibrous points, 
radiating from a central disk (fig. 2, c); and in all the coriaceous 
section, excepting C. levigatus, the basal tunic consists of a 
series of imbricated annuli surrounded by short teeth (fig. 2, D). 
In C. levigatus, in which the annuli are absent, the main tunie 
is split up at the base into a series of vandyke divisions 
(fig. 2, »), which in the first year clasp and protect the base of 
Fig. 2. 
Corm-tunics of Crocus. 
A & B. C. cancellatus. ©, D, E. C. Danfordie. F,G, H. C. levigatus. 
the corm. All these diverse structures, which have little relation 
to each other as regards pattern, are distinetly related to one 
common purpose—the reproduction of the eorm and its annual 
