143 
From Ponce long excursions in automobile were made, first 
n the thirteenth of March to Arroyo de los Corchos and on the 
fifteenth still farther on the same road to Jayuya. 
Arroyo de los Corchos is a dark wooded valley with an ex: 
ceedingly rich forest-vegetation, through which a little brook 
wound its way. Near the road the brook formed a little pond 
along the margins of which numerous Meuse grew. Among 
es e found several algae, Apa Gon- 
aaa and Calothrix. In the forest on rook was, on 
the contrary, conspicuously poor in algae, Beats because at 
most the places ae it ran there was too little light. Only 
at one place wl de a fall over a small rock were the latter 
and the stones red with saris, In the dark woo 
valley there were found epiphyllous algae, as ne re 
Ph ne EN Oe on the fronds of ferns, but on the m 
lighted earth and rock slopes along the road there existed a 
vegetation of the iM xophyceae characteristic of such ee 
t Jayuya, which is situated in the syenite region, the valle 
was rather flat, and there are, therefore, a number of larger or 
smaller collections of water along the river and the road. In 
the pools which were richer in organic ecnseen were found Phor- 
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besides desmids. On the stones in the brook were growing 
Stigeoclonium, Gongrosira, Hyella, and Pleurocapsa. 
igh waterfall ee iy a little brook on the road 
to Jayuya grew a great quantity of a species of Nostoc, hee 
had a warty surface and the size of peas or even of haze 
the eart rock-slopes along the road to ee were 
found aoe Ti sees and the common Myx ae 
vegetation, representatives of Oocystis, ae and the des 
mids. 
n general the ee of Jayuya may be regarded as a very 
good ae r alg 
All the places eh 1 had visited hitherto had comparatively 
great annual rainfall and consequently also in general a con- 
