vni. c, 5 Merrill: Philippine Melastomataceae, II 337 
has brought to light a surprisingly large number of undescribed 
forms, so that there are at present known from the Philippines 
alone about as many species of A stroma as are otherwise known 
from the entire range of the genus, that is tropical Africa, 
Malaya, and Poljoiesia. In the present consideration twenty-six 
Philippine species are recognized, and it is confidently expected 
that additional exploration will yield a considerable number of 
additional forms. 
r 
So far as can be determined at present all our species, with 
one exception, are confined to the Philippines; Astronia cumingi- 
ana Vid., a very common and widely distributed Philippine 
species, has been reported from Celebes by Koorders. Many 
are apparently of very local occurrence and are at present rep- 
resented but by solitary or few collections; othei-s are widely 
distributed in the Archipelago and range from northern Luzon 
to southern Mindanao. Most of them are found at medium and 
higher altitudes, although some occur at or near sea-level, espe- 
cially in those regions where the rainfall is not interrupted by 
a prolonged dry season. All the species are sylvan. The Prov- 
ince of Laguna, Luzon, presents no less than thirteen distinct 
species. Seven are found on Mount Maquiling and ten on, or 
about. Mount Banajao, but although these two mountains, both 
with forested slopes and both extinct volcanos, are not more 
than 30 kilometers apart, they possess, so far as our collections 
show, but four species in common. 
The most important character that the present study has 
demonstrated is that most if not all of the Philippine species 
are polygamo-dioecious, a character not hitherto given for the 
■genus, and one very rare in the family. It is suspected that 
the character will be found to hold true for the entire section 
Euastronia. Certain plants bear only staminate flowers, while 
others bear only 'perfect ones, the staminate flowers frequently 
not presenting even a rudimentary ovary. In eighteen of the 
twenty-six species considered, our collections present species in 
which the specimens are with male flowers only, or some with 
male flowers and others with perfect ones, the different kinds of 
flowers invariably being found on separate specimens. The eight 
remaining species are mostly represented by only one or two 
specimens. My attention was directed to this character first 
by finding on certain specimens only male flowers, and second 
by attempting to utilize certain calyx characters in the con- 
struction of a key. It was discovered that in those specimens 
presenting a cup-shaped calyx the flowers were invariably 
