characteristics

The known moss flora of the small West Indian island Saba (870 m in altitude) consists to date of48 species, while the neighbouring island St. Eustatius (600 m) has 40 species. The two islands have 27 species in common. Widely distributed neotropical species dominate at all elevations, while wide-tropical (i.e. pantropical) species are found mainly at middle elevations (300-600 m). Species with smaller geographical distributions (southern neotropical, Caribbean) are restricted to higher elevations (above 600 m).

An attempt has been made to determine the relation between mosses and the plant communities, encountered along the altitudinal gradient, by calculating “association values”, based on the results of random collecting. Four classes of association values have been distinguished: class A: very characteristic; class B: characteristic; class C: moderately characteristic; and class D: non-characteristic species. It appears that eight plant communities on both islands harbour one or more moderately to very characteristic species. Neckeropsis undulata is the only very characteristic species. It occurs in the evergreen seasonal forest on St. Eustatius. The results are compared with Guadeloupe, Martinique, Puerto Rico, Guyana and Suriname. Finally, a key to the species is included.

The present paper deals with the Anasca and Ascophora Imperfecta of the inland bays of Curaçao and Bonaire. Collections were made by P. Wagenaar Hummelinck (1930, 1936/ 37, 1948/49, 1955, 1963/64, 1968, 1970, and 1973) and by the author (1982), and stored in the collections of the Rijksmuseum van Natuurlijke Historie, Leiden. A total of 25 species – almost all occurring in inland bays – are described here and fully illustrated. Six new species are established: Crassimarginatella harmeri, Scrupocellaria curacaoensis, Scrupocellaria carmabi, Scrupocellaria piscaderaensis, Scrupocellaria hildae and Bugula hummelincki. Attention is given to the ecology of the species. The bays have been compared as to species composition in relation to substrate and conditions during collecting.

In 1930 Mr. P. Wagenaar Hummelinck made an excursion to Curacao, Aruba, and Bonaire with the main object of studying the land and freshwater fauna. In 1936 and 1937 he again visited these islands and, moreover, a.o. the island of Margarita off the Venezuelan coast, the Venezuelan peninsula Paraguana and the Colombian peninsula La Goajira (Wagenaar Hummelinck, 1940). In the various inland-waters also Algae and Phanerogams have been collected. The aquatic Phanerogams were described by Van Ooststroom (1939); the Charophyta will be the subject of the present paper.

As a result of these trips only two species of Chara were collected, one of which, viz. C. fibrosa , was new for the area under discussion. No representative of the other Charophyta genera was detected. Though several species are recorded from the north coast of South America (cf. Braun, 1858; Braun & Nordstedt, 1882), so little is known of the Charophyta of the Netherlands West Indian islands that it is worth publishing these few notes. Moreover, a number of ecological data were gathered, which are enumerated at the same time.