288 Ewart . — On the Stamina t Hairs of Thesium . 
S. Africa, but ascending, they are found successively in Asia 
Minor, Persia, S. Europe, and Australia ; then in Central 
Europe and Afghanistan ; the mountains of temperate 
Europe and in E. Siberia, and lastly in S. America and high 
up on the Himalayas. 
In the second series, passing from T. f unale to T. spicatum , 
the inflorescence is very crowded, the flowers being collected 
together into capitula, or dense spikes. 
These plants are only to be found in S. Africa. 
I have placed in the series the closely-allied genera of 
Quinchamalium , Arjona , Comandra , Osyridocarpos, and The si- 
dium. 
Thesidium only differs from Thesium in the dioecious 
character of its flower; it is a native of S. Africa, and falls 
naturally into the series. 
Osyridocarpos forms a connecting-link between Thesieae 
and Osyrideae, the flower is very similar to that of Thesium , 
except perhaps for the presence of a slightly developed disc ; 
but the leaves differ considerably, and the distribution does 
not accord with that of the rest of the series, Osyridocarpos 
being only found in S. Africa and Abyssinia. 
Comandra , which resembles Thesium in its flower, but has a 
very distinct disc, is found in Hungary and N. America, and 
agrees generally with the Thesiums of Central Europe. 
Arjona and Quinchamalium resemble the S. American species 
of Thesium in the general shape of the perianth, although the 
staminal hairs are modified in the one case, and altogether absent 
in the other. They are only to be found in South America. 
From the considerations given above it would seem probable 
that the ancestral home of the genus Thesium is S. Africa, 
where the species are at the present time more abundant than 
anywhere else, and that as they spread further north, their 
perianth became elongated and they lost their perianth- 
filaments, these no longer being required. The suggestion 
that the family Grubbiaceae represents an ancestral type of 
Santalaceae 1 would also strengthen this view, if correct, since 
Pflanzenfamilien, p. 229. 
