186 : BOTANICAL GAZETTE [MARCH 
The writer has been told by Mr. Wi1tt1AM Harris that in col- 
lecting at Dolphin Head, in the extreme west end of Jamaica at 
550 m. altitude, he observed only two species: 
Trichomanes sphenoides Kze. Trichomanes arbuscula Desv. 
On passing upward in the Blue Mountains from 1525 m., the 
Hymenophyllaceae are found to become fewer in both species and 
individuals. There is but a single form found only above 1830 m. 
(Hymenophyllum antillense Jenm.), while other species common and 
characteristic above this altitude are: 
Hymenophyllum tunbrigense Sm. Hymenophyllum lanatum Fee 
Hymenophyllum fucoides Sw. Hymenophyllum hirsutum (L.) Sw. 
Hymenophyllum asplenioides Sw. Hymenophyllum sericeum Sw. 
Hymenophyllum polyanthos Sw. Trichomanes crispum L. 
Hymenophyllum lineare Sw. Trichomanes pyxidiferum L. 
Judging by the ten-year rainfall record for Blue Mountain 
Peak (2264 m.) and by hygrograph records obtained by the writer 
at Sir John Peak (1890 m.), the conditions of rainfall and humidity 
are no less favorable for the filmy ferns at the higher altitudes than 
at 1525m.; indeed the percentage of cloudiness would appear 
from casual observations to be greater on the highest ridges and 
peaks. The mean annual temperature at Cinchona is 16 C., 
while that at Blue Mountain Peak may be closely approximated 
from a record of the monthly absolute maximum and minimum at 
that point to be 12°C. Although there are but few alpine features 
impressed upon the vegetation as a whole at the highest altitudes, 
yet the less abundance of the Hymenophyllaceae must be referre 
to the slightly lower range of temperatures rather than to less 
favorable conditions of rainfall and humidity. The scarcity of. 
species and individuals at low altitudes and at such localities 4S 
Mount Diablo and Dolphin Head, in the drier portions of the island, 
is obviously due to the lower rainfall, humidity, and cloudiness 46 
contrasted with the Blue Mountain forests. Where Hymeno 
phyllaceae occur at all below 915 m., or upon the drier leeward 
slopes of the Blue Mountains at greater elevations than this, they . 
re taken from the records of the Depart- 
ig l data for ] gp iod 
ment of Public Gardens and Plantations of Jamaica. 
