148 Parkin. — On some points in the 
cotyledons, often existing in great abundance in the leaves, 
stems, and especially the reserve-organs. Raphide-cells are 
very constant in character, only differing from one another in 
size and in the length of the individual crystal. The bundle 
of raphides does not fill the cell-cavity, but is suspended in 
a mass of mucilage. The nucleus and protoplasm originally 
present in the developing cell disappear when it is fully 
formed, as Hilgers 1 showed in the case of Polygonatnm. In 
tissue preserved in alcohol, the bundle is seen lying in the 
centre of the cell surrounded by a sheath composed of the 
precipitated mucilage. 
In the genus Iris the typical raphide-cells are absent, but 
crystal-sacs of a different kind are present. These contain 
each a large acicular crystal, and possess nuclei and proto- 
plasm, but no mucilage. They have been known for a con- 
siderable time, and have been investigated by Hilgers 1 in two 
species of the genus. De Bary 2 also refers to them. What 
I desire to point out is that intermediate stages occur in 
certain petaloid Monocotyledons between these two types 
of crystal-sacs ; although in using the term ‘ intermediate,’ 
I do not want it to be inferred that there is necessarily any 
genetic relationship between the two. The five cases which 
I have observed are found in Fnnkia ovata , Convallai ia 
majalis , Phormium tenax var. atropurpurea , Tritoma Uvaria , 
and Polianthes tuberosa. 
Funkict ovata. Raphide-cells of the usual large type exist 
in fair abundance in the leaf-lamina and petiole (Figs. 1 and 2). 
Besides these, however, there is another kind of crystal-cell, 
which is more widely distributed in the plant, occurring in 
the leaves and root-stock. They might, without special 
attention, be passed over as ordinary raphides. The petiole 
is a gcod region in which to observe these two forms. By 
carefully examining transverse and longitudinal sections the 
differences between the two become very manifest. 
1 Hilgers, Pringsheim’s Jahrbiicher, Vol. vi, 1867-68, p. 285. 
2 De Bary, Comparative Anatomy of Phanerogams and Ferns, p. 138: he 
refers to Unger’s Anatomic und Physiologie, 1855. 
