Ewart.— 07 t the St diurnal Hairs of Thesium. 277 
The nearest is in Arjona , but here each hair is attached 
separately to the perianth itself. In many diagrams of 
Thesium flowers, the hairs are omitted entirely, e. g. T. ros - 
tratum , by Reichenbach 1 ; T. intermedium and T. humile 2 . 
Development of staminal hairs. — In the youngest flower- 
buds which I examined, the staminal hairs were already 
formed and projected from the surface of the perianth, but 
the basal cushions were only slightly, if at all enlarged. 
In a very young bud of T. spicatum the thick downwardly 
directed hair as yet only contained very dense granular proto- 
plasm, and looked as if it were merely a much modified and 
elongated epidermal cell. The protoplasm had become con- 
tracted by the alcohol and had receded from the membrane. 
The constrictions at the free end had already made their 
appearance. A later stage of the same species showed that 
the basal cushions were larger and that the constrictions at 
the free end of the hair had become more pronounced ; the 
secretion was being formed by the protoplasm in the fila- 
mentous portion of the hair as well as in the thicker basal 
part. The secretion first becomes apparent as a number of very 
minute, yellowish globules, embedded in the granular proto- 
plasm ; these coalesce to form larger masses until very little 
protoplasm remains, and the hair is mature as shown in 
Fig. 2. The formation of the secretion within the hairs 
bears a strong resemblance to that of the fatty globules in 
adipose tissue of animals. 
In Fig. 6. an intermediate stage is given in the development 
of the hairs of T. capituliflorum , where the globules are as 
yet only scantily formed. In all these young stages the 
contents of the cell were more or less contracted away from 
the membrane by the action of the spirit in which they had 
been preserved. 
In older flowers the hairs are usually empty, and shrivelled 
in appearance, but the layer of cells immediately below the 
epidermis, and bordering on the upper side of the basal 
1 Iconogr. Bot. 1827. 
2 Gtissone Plant, rarior. t. 20. 
