280 Ewart . — On the Staminal Hairs of Thesium, 
there are other structures in flowers of Thesium to be noticed, 
which seem to be closely correlated with the staminal hairs. 
The pendent filaments of the perianth-lobes in T. capituli- 
florum have already been mentioned in the general descrip- 
tion of that flower. They are very long and composed of 
elongated cells forming a thick column at the upper part, 
three or four cells in breadth, and gradually taper off towards 
the free end (Fig. 14, fit). In young flowers the cells are 
oblong and regular ; but in older stages they become cor- 
rugated. The apices of the perianth -lobes are much 
thickened in this species to form a ‘ hood ’ over the anther 
(Fig. 14, c ) ; the style is short, and the pendent filaments 
reach to the stigma. 
In 7 . spicatum the characteristics of the former species are 
more pronounced ; the pendent filaments are very abundant 
and form a thick veil in front of the anthers. 
In T. alpinum , which possesses staminal hairs of the second 
class, the inner surface of the perianth-segments is covered 
by a thick layer of elongated cells, somewhat conical in 
shape, as shown at e in Fig. 7 and 9. These cells also 
line the lateral flaps of the segments which fold over the 
anther in front, and enclose it in a cylindrical chamber open 
above and below. Fig. 7 shows a transverse section of the 
perianth-lobe taken at the level D in Fig. 9. There is no 
thickening or ‘ hooding’ of the perianth-apex in this species, 
and the stigma is almost on a level with the top of the 
anther, the perianth-tube and the style being both much 
elongated. 
In T. paniculatum the apex of the perianth-segments is 
thickened, and from its lower surface and lateral margins 
hang small projections, composed of groups of four or five 
rounded cells. Fig. 8 shows two of these groups situated 
on the lateral margins of two adjacent segments. (In the 
same figure is seen the way in which the segments dovetail 
together before the flower is fully opened ; this arrangement 
seems to be general throughout the genus, and may also 
be seen indicated in Figs. 9 and 14.) 
