319 
Stapf. — On the Sonerileae of Asia. 
From these facts we may, without losing ourselves in too 
uncertain speculations, draw a few conclusions with regard 
to the phylogenesis of these Sonerileae. 
1. Thus the 3-staminal Sonerileae appear as the reduced 
offspring of forms with two penta-, tetra- and trimerous 
staminal whorls. Brittenia , P hyllagathis , Gymnagathis , Fordio- 
phyton , and Sarcopyramis are still at this earlier stage of 
evolution. In Sonerila it is preserved only in S'. Bensonii 
and in the species of the obliqua-gr oup. 
2. The Sonerilas belong to two different lines of descent 
which have diverged from a common stock probably 
in very remote times. One line may be traced back to 
an origin which is indicated at present by S. Bensonii , or the 
speciosa-group ; the other may be supposed to have started 
from a type near to or identical with the obliqua-gr onp. 
3. Therefore the subgeneric name Genuinae, should be 
applied to the first set ; Sonerilopsis to the rest, viz. the groups 
of S. obliqua and S. moluccana. Of these two, Sonerilopis 
is decidedly nearer to the old type, which is represented by 
the genera Brittenia , P hyllagathis , Gymnagathis , Sarcopy- 
ramis and Fordiophyton , with which it has the characteristic 
nervation of the leaves in common. 
These deductions are supported in a very remarkable way 
by the geographical distribution of the Asiatic Sonerileae. The 
list at the end of this paper shows this more clearly. In this 
list Nos. 1-49 comprise the Sonerila § Genuinae , 50-71 the 
Sonerila § Sojterilopsis and the remaining genera. Out of 
the 49 Genuinae , twenty-three are found in Ceylon and the 
Western Ghats, and only ten in the Malayan Archipelago 
and the Malayan Peninsula, and these belong [all but three] 
to the tenuifolia-growp , which is so closely allied to the 
western zeylan ica-group, and one is S. zeylanica itself. 
The groups of S', linearis and of S. scapigera are also 
represented by a few species in Ceylon and the Western 
Ghats, whilst that of S. maculata approaches, partly at least, 
S. pilosula , again a Ceylon species. On the other hand 
