Ewart, — On the Stamina l Hairs of Thesium. 273 
tinuous with the basal cushion and tapers towards the free 
extremity. Here it exhibits three remarkable constricted 
rings (Fig. 6, c v c 2 , c 3 ), and a small rounded terminal cap (c), 
an arrangement which appears to serve a particular purpose, 
as will be demonstrated later. Apparently the hairs are uni- 
cellular, for I was unable to find a septum, or even indications 
of one, between the broad basal cushion and the projecting 
portion of the hair, at any stage in the development of the 
flower. Each hair is filled with droplets of a yellowish-green 
semi-fluid secretion, lying in a protoplasmic meshwork ; these 
droplets produce the yellow colour of the hairs. In older 
flowers the hairs are colourless and empty, and their terminal 
caps appear to have been broken off. The cuticle of the hair 
is thin, and exhibits no special markings. The basal cushion, 
as well as the projecting portion of the hair-cell, contained 
globules of the yellow secretion ; but in this species I was 
unable to find a nucleus, although in the surrounding enlarged 
cells they became conspicuous after staining with methyl- 
green. 
The staminal hairs in T. spicatum closely resemble those 
just described. They are shorter and thicker, and conse- 
quently the three terminal constrictions are more evident 
(Fig. 2, c lf c 2 , c 3 ). In many, the terminal cap is seen to be 
broken off, the separation always occurring along one of the 
constricted zones. In Fig. 3 the separation has taken place 
at the middle one, in Fig. 4 at the lowest. In all cases where 
it has happened only the empty membrane of the hair re- 
mains, all the yellow secretion having escaped. The basal 
cushions of these staminal hairs are large, and the secretion 
developed in them forms large globules which separate out 
from the protoplasm of the cell. I was able to distinguish 
a nucleus in the basal portions of two of the hairs (Fig. 1, n). 
In a transverse section of the flower, at the level of the hairs, 
the long axis of the enlarged base is seen to be at right angles 
to the surface (Fig. 1, das), but in a longitudinal section the 
base has a more circular figure (Fig. 2, das). The grouping 
has been carried further in this species, the ten chief regions 
