THE FLORA OF MANILA. 
201 
for their reproduction and growth, it is interesting to note that a 
number of forms are found in none of the other countries of the 
Eastern Hemisphere, while others are just commencing to estab- 
lish themselves in neighboring regions. Many of these American 
aliens in the Philippines that have not reached neighboring coun- 
tries are among our most common and widely distributed species, 
while others are of local occurrence only. In connection with 
this matter the following species may be mentioned; Alternan- 
thera frutescens R. Br., common in waste places ; Portulaca pilosa 
L., occasional in dry localities; Anredera scandens Moq., very 
abundant in hedges and thickets along streets; Pithecolobium 
didce Benth., very common in the Philippines, and thoroughly 
naturalized, thriving especially on gravel bars along many 
streams, now also scattered in Java and in India; Prosopis vidal- 
iana Naves, described from Philippine material, and by some 
authors reduced to P. juliflora Sw., certainly of Mexican origin, 
and now very abundant about the shores of Manila Bay; Desmo- 
dium scorpiuris Desf., abundant here, also in Polynesia; Gliri- 
cidia sepium Steud., very abundant in the Philippines, and now 
just beginning to appear in neighboring countries in the Orient; 
Parosela (Dalea) glandidosa Merr., very abundant on dry grassy 
slopes and in waste places, first described by Blanco; Schrankia 
quadrivalvis (L.) Merr., rare, or at least very local; Muntingia 
calabura L., also in Siam, introduced there from Manila; Mal- 
achra fasciata Jacq., abundant in waste places, now occasional in 
Java, but still rare there ; Ipomoea trUoba L., very common in the 
Philippines and in Guam, now making its appearance in Singa- 
pore, Borneo, Java, and Mauritius; Hyptis capitata Jacq. and H. 
spicigera Lam., both also in Guam, the former also in Java, but 
still rare there; Blechum brownei Juss., abundant in Guam and in 
the Philippines, now also in Formosa; Elytraria tridentata Vahl, 
abundant locally; Elephantopus mollis HBK., also in Guam, and 
E. spicatus Pers., among our most common and widely distributed 
weeds ; Rotala ramosoir Koehne, now a common rice paddy weed 
with us ; Cenchrus echinatus L., very common, now also occasional 
in neighboring countries, Borneo, etc., and Eleutherine americana 
Merr., occasional in some parts of the Philippines, locally 
abundant. 
The presence of these American weeds in the Philippines is 
directly due to the old Acapulco-Manila trade route, and indicates 
the necessity of taking into consideration the communication 
between different countries in working out problems regarding 
the introduced element in any particular region. 
