CELL CONTENTS 205 
instance, are blue or violet. Most of the smaller rosette crystals, 
however, appear grayish white with a darker-colored centre. 
Rosette crystals occur in parenchyma cells (Plate 81, Fig. 4) 
and in medullary rays (Plate 81, Fig. 3). 
SOLITARY CRYSTALS 
Solitary crystals are the most variable of all the forms of 
calcium oxalate. They usually occur in crystal cells associated 
with bast fibres and stone cells, less frequently in stone cells 
(Plate 33, Fig. 2). There are many different and characteristic 
forms of prisms. ‘The more common are: 
1. Rectangular: 
A. Parallelopipeds. 
B. Cubes. 
2. Polyhedrons: 
A. Irregular polyhedrons. 
I. Flat bases. 
(a) Non-notched. 
(b) Notched. 
II. Tapering bases. 
B. Octohedrons. 
The crystals occurring in Batavia cinnamon and henbane 
leaves are parallelopipeds (Plate 82, Figs. 1 and 2). 
The crystals occurring in cactus grandiflorus, hemlock bark, 
krameria root, and soap bark are irregular polyhedrons (Plate 
83). They are longer than broad, and the ends are tapering. 
The crystal of cactus grandiflorus has the narrowest diameter 
of these four, while the crystals of soap bark have the widest 
diameter. In coca leaf, xanthoxylum bark, elm bark, Spanish 
licorice, and in white oak (Plate 84), and in cocillina bark (Plate 
82, Fig. 4) the crystals are all irregular polyhedrons with flat. 
bases. They are mostly longer than broad and they are all 
widest in the centre; in each a few crystals are notched, but 
most of the crystals are not notched. : 
The crystals in quassia wood, uva-ursi leaf, and most of those 
of quebracho and wild cherry bark (Plate 86, Figs. 1, 2, 3, and 4) 
are irregular polyhedrons with flat ends. They are longer than 
broad, widest at the centre, and non-notched. 
Cubes occur in senna, cascara sagrada, frangula, white pine, 
