Histology of Monocotyledons. 1 5 1 
Convallarieae, Asparageae, Dracaeneae, Pontederiaceae, and 
Amaryllidaceae. Then in addition to the ordinary raphide- 
cells, Funkia , Convallaria , Phormium , and Polianthes possess , 
crystal-sacs without mucilage ; while Tritoma appears to have 
the latter only. 
Funkia , Phormium , and Tritoma belong to the tribe 
Hemerocallideae ; Hemerocatlis fulva and H. flava, both of 
which I have examined, contain ordinary raphide-cells, but 
not the other type of crystal-sac. The Convallarieae come 
very near the Hemerocallideae in habit, differing chiefly in 
the baccate fruit. Thus the four genera, Funkia , Phormium , 
Tritoma , and Convallaria seem fairly closely allied. Polianthes 
is placed among the Agaveae, a sub-order of the Amaryl- 
lidaceae. It is generally considered that the Amaryllidaceae 
have been derived from the Liliaceae by the ovary becoming 
inferior, and sometimes it is inferred that the Iridaceae have 
arisen from the Amaryllidaceae. It may be that the Iridaceous 
forms began to appear just about the time the Amaryllideae 
were evolving, both having a common origin in some Liliaceous 
type. The similarity of the crystal-sacs would support 
a relationship between the Iridaceae and the Liliaceous tribe 
Hemerocallideae. 
A special study of these crystals, which are formed in the 
growing organs, and hence belong to Schimper’s class of 
primary calcium oxalates, might be of value from a phylo- 
genetic point of view, as well as a means of throwing light on 
their function, of which at present we seem very ignorant. 
II. An absciss-layer in THE LEAVES of Narcissus , 
Galanthus , AND Leucojum (Figs. 13, 14). 
Having had occasion to examine species of Narcissus , 
Galanthus , and Leucojum at various stages in their annual 
growth, I observed that the foliage does not simply die down 
and wither away, but that each leaf is detached from its 
tunicate base (bulb-scale) by means of a layer of cells 
M 
