672 Part IV. Chapter 7. 
The ground of the savannas in Panama is clothed with a turf of brilliant green consisting 
of Seleria nutans, Rhynchospora comata, Paspalum distichum, P. irrigatum, Panicum maximum, 
Eragrostis eiliaris, and Papilionaceae, Polygalaceae, Gentianaceae, Violaceae. Groups of trees and 
bushes rise here and there. The trees belong, according to HEMSLEY, to such orders as Myr- 
taceae, Melastomaceae, Chrysobalanaceae, Papilionaceae, Verbenaceae, Compositae, Dilleniaceae, 
Anonaceae, Malpighiaceae, Besen ceae overspread by plants of the Convolvulaceae, Aristo- 
> Apocynaceae and climbing plants of other natural orders, and such ferns as Pteris 
ag ‚ Schizaea ah The chumicales, or groves of sand-paper trees, Curatella ame- 
rican vo curious features of the landscape. 
Se FORMATION. The potreros in Costa Rica, according to RıpGwAy, are covered 
with trees supporting vines and epiphytes. Near the streams tree ferns are common. The high 
potrero (9,000 feet) at the base of the ash cone of Turrialba is a park-like savanna with groves of 
PoLAKOWSKY mentions the plants of the potreros as Alternanthera achyrantha, Dalea alopecuroides 
Hyptis pectinata, Marsypianthes hyptoides, Mimosa pudica, M. invisa, Muhlenbergia tenella, Poly- 
gala paniculata and species of Panicum and Paspalum. 
Catingas Formation. POLAKOWSKY speaks of the Catingas of Costa Rica using that 
word in the Brazilian sense, where this formation typically exists. The light forests (Catingas), 
which exhibit the phenomenon of the fall of the leaf and stand during the hottest, driest season 
stripped of all their foliage remind the traveller of the northern forests in their leafless winter 
condition. With the first rains, the trees become clothed with green foliage. These stand in 
the Costa Rican region interspersed with the open forest found rarely away from the Pacific 
side, and savannas) in the central and western parts of Nicaragua and in Guanacaste in Costa Rica. 
Chapter VII. North American Tropic Zone: West Indian Section. 
The floristic section of the West Indian Islands includes three distinct 
regions, viz.: the Antillean, the Bahaman and the Bermudan. Each of 
these regions is characterized by a flora which owes its character to climatic, 
historic and edaphic factors. The high mountain chains in the Antillean 
region with numerous freshwater rivers and streams give to its flora a diversified 
character not possessed by the flora of the Bahama and Bermuda islands, 
which are generally low, calcareous and without running streams. The flora 
of the Greater Antilles possesses in many places the tropic luxuriance of a 
rain forest, while in the Bahamas, the plants are more or less xerophytic 
and the arborescent vegetation in the nature of chaparral, rather than asso- 
ciated together into a true forest. Besides the flora of the Bahama, and 
especially the Bermuda islands, is derivative, while that of the Antillean is- 
ands is much older and represents the remnants of a flora which was coin- 
cident with the former Antillean continent?). 
1. Antillean Region. 
This includes the islands of Cuba, Jamaica, Santo Domingo, Puerto 
Rico and the Virgin islands. The Lesser Antilles are excluded because 
1) NIEDERLEIN, G.: The Republic Costa Rica P- 34; see mug p- 85. 
2) See ante, pages 122, 305—310; Cfr. JoHunsTon, Jonn R Slene er the Islands of Marga- 
rita and Coche, Venezuela. Proc. Boston Soc. Nat. Hist. XXXIV 163—312. 1909. 
