50. RUBIACEZE OF CENTRAL AMERICA. 
‘peculiar to this flora are: Pentagonia, Lindenia, Ravnia, Xerococcus, and 
Ophryococcus. Psychotria (15), Palicourea (6), and Rondeletia (6), 
contain the most species. The genera, which are rich in species in 
adjoining countries, but either entirely wanting here, or scantily repre- 
sented, are principally Cephaelis, of which only one species is met with, 
while there are 15 in Guiana; Coffea and Faramea, which are absent 
altogether, but abound in species in Guiana. Of Spermacocee, whose 
great extension may be attributed to their being for the most part weeds, 
only one species is peculiar to this flora, namely Crusea longibracteata, 
Benth.; but most species of the. other sections are peculiar ; such as 
9 out 15 species of Psychotria, all Palicouree and RHondeletie, etc. 
Central America has altogether 14 species in common with Mexico*, 
21 with the Antilles, and 16 with South America}. This community 
in regard to a great number of species with the Antilles, corresponds well 
with that dissemination to which J. D. Hooker has first drawn atten- 
tion in his memoir on the Galapagos Archipelago, so highly important 
to the geographieal botanist; namely, that most of the plants of 
those islands, which are not endemical, are common not only to 
Central America, but also to the Antilles: so that, since none of the 
Galapagos typical forms occur on the Continent, it must be presumed, 
that the former, being favoured by the western oceanic currents, have 
extended from the Antilles, which must accordingly be considered as 
their head-quarters$. Some species are widely spread over the entire 
tropical America, namely Borreria verticillata and parviflora, Spermacoce 
tenuior, Chiococca racemosa, Hamelia patens, Coccocypselon canescens, 
and Oldenlandia herbacea, which last appears likewise in all other 
countries of the world. It is probable, nevertheless, that a greater ac- 
* Galium uncinulatum, Rubia hypocarpia and levigata, Borreria verticillata and 
Henkeana, Spermacoce tenuior, Richardsonia scabra, Chiococca racemosa, Gonzalea 
spicata, Mitracarpium schizangium, Psychotria hebeclada, Palicourea mexicana, 
Oldenlandia herbacea, and Manettia cuspidata. 
+ Rubia hypocarpia, Borreria verticillata, parviflora, aud Bartlingiana, Sperma- 
coce tenuior, Diodia prostrata and barbata, Mitracarpium villosum, Cephaelis pu- 
nicea, Psychotria pubescens, nervosa, and levis, Nonatelia panamensis, Irora ferrea, 
Chiococca racemosa, Hamelia patens, Gonzalea spicata, Oldenlandia herbacea, 
Manettia cuspidata, Exostemma caribeum, and Calycophyllum candidissimum. 
i Borreria verticillata and parviflora, Diodia barbata, Psychotria nervosa, he- 
beclada, flexuosa, and alba, Chiococca racemosa, Oldenlandia herbacea, Alibertia 
edulis, Coccocypselon canescens and hirsutum, Genipa Caruto, Posoqueria longiflora, 
Calycophyllum candidissimum, and Condaminea corymbosa. 
§ Transactions of the Linnean Society, vol. xx. p. 163-262. 
