XI 
Collecting on land also has its hazards. Shortly after his first 
few trips ashore at Ascension Bay, Br. Clarke developed the most severe 
case of 'poison ivy.*’ This time he was having a "taste" of our Barbuda 
experience of the previous year. His hand and lower forearm became pain- 
fully swollen, Inflamed, and blistered, nor did his face and neck escape. 
In hacking his way through the brush he must have come in contact with 
the sap of a shrub related to our old friend the cashew nut (family 
Anacardiaceae, genus Comocladia ) , not uncommon In the thickets and scrubby 
forests of some of the drier areas of the Caribbean and in Mexico, as in 
Barbuo-i . The juice of all species of the genus is extremely poisonous, 
and of some so corrosive that in parts of the West Indies it is used to 
cure ringworm and to destroy warts, but such use can be dangerous. 
Several weeks elapsed before the attack subsided and Dr. Clarke could 
work in comfort and without endlessly renewed wrappings of paper towels 
and applications of calamine lotion, of which fortunately we load a good- 
sized bottle along. It is to be recommended for- one’s tropical American 
medicine chest. 
The great mangrove swamp area in Ascension Bay must be several 
square miles in extent . In a recent account dealing with mangroves, 
and this swamp in particular, which Dr. Dalber published in the Estuarine 
Bullet ine (Univ. Delaware, vol. 5 > No. 2 , June i960), he remarked that 
"the trees, spread out into depths of water where young seedlings could 
no longer become rooted to the bottom. ..so the mangrove front was being 
advanced by the elongation of prop-roots rather than by new seedlings. 
