THE FLOKA OF PANAMA. 165 



" Ipomcea pescaprce grows here in the wildest luxuriance, spreading its stems for 

 200 feet over the sandy dunes. The poisonous manzanilla tree (Hippomane mancinella) 

 also flourishes in great profusion. The cocoa-nut palm, which is the finest and most 

 beautiful of the trees of this zone, though succeeding tolerably well on the loose sandy 

 soil of the coast, where it is exposed to the lashing of the breakers, grows to much 

 greater perfection on the firmer ground further inland ; and Acrostichum aureum covers 

 wide tracts near it. Cr essentia cucurbitina and Paritium tiliaeeum often form almost 

 impassable thickets round the cocoa-nut palms. At the mouths of the rivers Bhizophom 

 and Avicennia, which always appear together, are conspicuous. The mangrove (Bhizo- 

 phora mangle) forms impenetrable woods for about two nautical miles inland ; its gnarled 

 and crooked branches spread on all sides and bear numbers of aerial roots, which reach 

 down to the ground. 



" 2. The zone of tropical Forests of tall Evergreen Trees. — The undergrowth is not 

 luxuriant, and is formed chiefly of monocotyledons. This zone forms a belt on the 

 Atlantic side, which is bounded by the littoral zone, and is twenty to twenty-two nautical 

 miles broad in its centre. The trees here seldom lose their leaves. The zone lies 

 within the limits of the damp precipitation, and is bounded on the south by the savana 

 zone, where the drying trade-winds sweep over the country. Here abound great numbers 

 of Eubiacese, Myrtacese, Melastomacese, Sterculiacese, Euphorbiaceee, and Anacardiaceae ; 

 fewer palms occur, and these consist chiefly of remarkably small species, such as Chamas- 

 dorea friedrichsthaliana, Trithrinax warscetviczii, and Bactris subglobosa, associated with 

 beautiful species of Cycadacese, Scitaminese, and Bromeliacese. Among epiphytal and 

 parasitical plants the Orchidese, Piperacese, Bromeliacese, and Loranthacese are most 

 richly represented. 



" 3. The Savana zone. — This only exists on the Pacific side of the isthmus, where 

 it forms a grassy belt sixteen to eighteen miles broad, lying between the foot of the 

 Cordilleras and the littoral zone of the Pacific Ocean, where the grass is interspersed 

 with strips of woodland. This zone gives a lovely garden-like appearance to the 

 southern landscape, and is far the most important for colonization. The trees and 

 bushes seldom reach to the height and beauty of those of the damper wooded zone, 

 except on the river-banks. Only such trees thrive as can stand the strong light and 

 the four months of dry season, during which many of them lose their leaves. The 

 grass, though partly creeping, is not thickly matted together. Digitaria marginata 

 and Paspalum notatum are the most abundant species. Paspalum virgatum, Setaria 

 glauca, Panieum maximum, Eragrostis ciliaris, Isolepis junciformis, Cyperus flavo- 

 mariscus, Bhynchospora comata, and Scleria nutans are especially numerous. 



"The Polygaleae, Sauvagesise, Papilionacese, Ericaceae, Euphorbiacese, Capparidese, 

 and Iridese are the most numerously represented orders. In June and July the most 

 beautiful flowers are Polygala longicaulis and Sauvagesia pulchella. The well-known 



