THE FLOKA OF PANAMA. 161 



moisture that leather cleaned in the morning is densely covered with mould in the 

 evening. The temperature does not vary more than from 75° to 87° Fahr. Towards 

 the end of December the violent rains diminish in frequency, and with the commence- 

 ment of the new year the north-west wind sets in. An immediate change follows ; the 

 air becomes pure and refreshing, the sky blue and serene, hardly a cloud is to be seen, 

 and, there being but little moisture in the atmosphere, the heat, though ranging between 

 75° and 94° Fahr., is less felt. 



" A country so much visited by heavy rains naturally abounds in rivers ; the number 

 cannot fall short of two hundred, and during the wet season not a mile of land can be 

 traversed without crossing at least five or six periodical streams. Most of the rivers 

 have deltas, which, in many instances, assume the appearance of islands. Their vege- 

 tation is a curious mixture of littoral and inland plants, and often presents species from 

 the higher mountains, to which the remote sources of the water may be traced. Of 

 these rivers emptying themselves into the Pacific Ocean, the San Juan, Churchunque, 

 Bayano, Eio Grande de Nata, Santa Maria, Tavasara, and Chiriqui are the largest; of 

 those flowing into the Atlantic, the Belen, Veraguas, Chagres, and the nine-mouthed 

 Atrato. Nowhere is the vegetation more luxuriant than on the banks of these rivers. 

 Wild fig-trees form great bowers over the bed, evergreen Pithecolobiums emit a delicious 

 perfume, bamboos (the most gigantic of grasses) show their feathery tops, groves of 

 vegetable-ivory palms display their foliage ; to whatever spot the eye is directed it 

 meets fresh beauties, new charms. 



" The aspect of the flora is much more diversified than the uniformity of the climate 

 and the surface of the country would lead one to expect. The sea-coast and those parts 

 influenced by the tides and the immediate evaporation of the sea produce a quite 

 peculiar vegetation, which is generally characterized by a leathery glossy foliage and 

 leaves with entire margins. In all muddy places, down to the verge of the ocean, are 

 impenetrable thickets formed of mangroves, chiefly Bhizophora and Avicennia, which 

 exhale putrid miasmata and spread sickness over the adjacent districts. Occasionally 

 extensive tracts are covered with the ' guagara de puerco ' (Acrostichum aureum, Linn.), 

 its fronds being as much as ten feet high. Myriads of mosquitoes and sand-flies fill 

 the air ; huge alligators sun themselves on the slimy banks, lying motionless, blinking 

 with their great eyes, and jumping into the water directly any one approaches. To 

 destroy these dreaded swamps is almost impossible ; the Avicennias, with their asparagus- 

 like rhizomata, send up innumerable young shoots whenever the main stem is felled ; 

 the Ehizophoras extend in all directions their long aerial roots, which soon reach the 

 ground and preserve the trees from falling' after the terrestrial roots have lifted them 

 high above the original level. At Panama, where the tide rises to the height of 

 twenty-two feet, these trees are frequently under water, the heavy surf washing their 

 tops, apparently without injuring or checking their growth ; indeed, so well has Nature 

 provided for them, that the seed of the Bhizophora begins to germinate while the 



biol. cekte.-ameb., Bot. Vol. IV., August 1887. y 



