Ewart. — On the Staminal Hairs of Thesium. 283 
other structures of the flower with the modifications of the 
staminal hairs, as shown in the above series, seems to throw 
some light on their probable use to the plant. A. De Can- 
dolle 1 in 1857 called attention to the hairs, and suggested 
that they probably served some part in the pollination of the 
flower ; they have been regarded as a nectary 2 ; and in 
Engler and Prantl’s ‘ Pflanzenfamilien ’ (Santalaceae), p. 20 6, it 
is stated that they probably serve as a collecting apparatus 
for the pollen, and ‘ are specially fitted to prevent the pollen- 
grains from falling into the cavity of the flower.’ 
Insect visits have been observed in Thesium by Muller 3 , 
and that this is probably the usual method of pollination may 
be inferred from the presence of a nectar-secreting ‘ disc * in 
some of the species, e. g. T. finale [nee, Figs. 12 and 13), and 
T. triflorum. In the genus Thesium , the disc is usually not 
well developed, but in neighbouring genera, e.g. Osyridocarpos 
and Comandra , it is quite conspicuous, and is frequently drawn 
out into lobes between the perianth-segments. 
In Arjona , Comandra , and other genera in which the disc 
is developed, the staminal hairs are present in great abun- 
dance. In Comandra , Nutt. (Bastard Toadflax), the adherent 
disc is said to have ‘ five free lobes, stamens inserted between 
these, opposite the lobes of the calyx, to the middle of which 
the anthers are connected by a bundle of threads 4 .’ Hence 
the function of the hairs can scarcely be that of a nectary 
merely, this office being performed by the cells of the disc. 
Again, it might be argued that they act as supports to the 
stamen, being firmly bound in so many cases by their secre- 
tion to the anthers, and so preventing any displacement of the 
stamens. I incline to the view that the close adhesion of the 
staminal filaments to the anthers is incidental, and due rather 
to the nature of the secretion, than to any special function of 
support. 
1 Note sur la fam. Santal. in Bibl. Univ. Geneve, 1857. 
a Mert. and Koch. Deutsch. Flor. p. 281. 
3 Engl, and Prantl’s Pflanz. (Sant.) p. 208. 
4 Asa Gray, Bot. U. S. p. 397. 
