Ewart . — On the Staminal Hairs of Thesium . 289 
the lower converging species of the series of Thesium given 
above would most closely resemble the members of its solitary 
genus Grubbia , with their small perianth and short truncate 
or slightly-lobed style, with their closely-packed inflorescences, 
and with their stamens inserted at the base of the perianth. 
The species of Grubbia are natives of S. Africa. 
EXPLANATION OF FIGURES IN PLATE XVI. 
Illustrating Miss Ewart’s Paper on the Staminal Hairs of Thesium. 
Fig. 1. Thesium spicatum, L. Part of transverse section of flower, taken 
through the level of the staminal hairs. The basal cushions of the hairs are large, 
and contain protoplasm and globules of secretion, b. The filamentous portions 
are inclined downwards, and are consequently cut across in a transverse section. 
Faint markings are shown on the cuticle at a. u, nucleus; has , basal cushion of 
staminal hair ; /, stamen filament. x 195. 
Fig. 2. Do. Longitudinal section of flower, through a single staminal hair. 
The constricted zones c u c 2 , c 3 , and the terminal cap, c, are well shown, has, 
basal cushions of hairs ; a , cuticle of hair ; g, inner surface of base of perianth, 
x 125. 
Fig. 3. Do. Free end of staminal hair, from which the terminal cap and upper 
part have broken away, the separation taking place along the constricted zone c 2 . 
a, cuticle of hair, x 450. 
Fig. 4. Do. Two staminal hairs from an old flower. The terminal caps have 
broken away and the secretion has escaped, leaving the empty cuticle which shows 
slight markings. A mass of pollen-grains, pol , are entangled with the hairs, e, 
epidermis covering the inner surface of the perianth. x 300. 
Fig. 5. Thesium debile , R. Br. Free ends of staminal hairs at various stages : 
i, without terminal cap, separation having taken place at c 2 ; v, the same, but 
separation having occurred at c L ; iii, terminal cap incompletely separated ; ii, iv, 
typical ends of hairs, x 490. 
Fig. 6. Thesium capitulijiorum, Sond. Longitudinal section of very young 
bud, passing through a staminal hair, bas , basal cushions of hairs ; p, protoplasm 
of hair; d , b, globules of secretion; a, cuticle of hair; g, base of perianth, inner 
surface, x 280. 
Fig. 7. Thesium alpinum . Diagrammatic transverse section of perianth-seg- 
ment, at level D in Fig. 9. The anther, n, is enclosed by lateral flaps, jl, of the 
perianth, lined on both sides by elongated cells, e. v, vascular bundles, x 44. 
Fig. 8. Thesium paniculatum, L. Part of transverse section of flower, pass- 
ing through two adjacent perianth-segments. From the inner margins of each 
