Psilotum nudum

Daniel, Thomas F., 2020, Notes on the Vascular Flora of the Island of Príncipe (São Tomé and Príncipe) in the Gulf of Guinea, Proceedings of the California Academy of Sciences 66 (15), pp. 341-352 : 348-350

Psilotum nudum (L.) P. Beauv.

Príncipe: between Água Grande and Praia Bom Bom, ca. 10 m above and behind ( SE of) high tide line, 01°41ʹ24.3ʺN, 007°23ʹ59.4ʺE, ca. 3 m, strand vegetation with Cocos nucifera , 24 IV 2013 (fertile), T . Daniel & J . Shevock 12035 ( CAS) .

More than 100 plants of this distinctive pteridophyte were frequent on and around the bases of numerous coconut palms in the beach sands at the northern end of Príncipe ( Fig. 3 ). The family and species are newly reported as naturally occurring plants on that island. Psilotum nudum was noted previously to occur in one locality (Praia Melão) on São Tomé ( Figueiredo 2002; Klopper and Figueiredo 2013). Elsewhere among the islands in the Gulf of Guinea, P. nudum occurs on Bioko and Annobón (e.g., Velayos et al. 2008, 2013a).

In their updated checklist of ferns and lycophytes in the country, Klopper and Figueiredo (2013) cite 157 species (no species is represented by more than a single infraspecific taxon), with 145 on São Tomé and 77 on Príncipe. Three species of ferns were treated as naturalized, two occurring on both islands and one only on São Tomé. Among the 15 species of lycophytes in the country, 12 occur on São Tomé and eight occur on Príncipe; five species occur on both islands, seven are known only from São Tomé, and three are known only on Príncipe; one species is endemic to both islands, and one species is endemic to São Tomé. With the addition of Psilotum nudum on Príncipe, Table 2 provides a summary of the numbers of native and endemic species of ferns and lycophytes for the country and for each of its islands.

TABLE 2. Numbers of native species of ferns and lycophytes in São Tomé and Príncipe by country and by island. See text for additional explanation.

ST & P ST P

Total natives 154 142 76

Occurrences 62 1 78 14 Endemics (% per region) 2 2 (1%) 7 (5%) 3 (4%)

1 common to both islands

2 common to both islands; total for the country = 12 (8%)

Figures

FIGURE 3 Miscellaneous vascular plants. Psilotum nudum (top), fertile plants on base of coconut palm (Daniel & Shevock 12035). Sciaphila ledermannii (bottom left), fertile plant (Daniel et al. 12085, photo by M. Nadel). Sciaphila ledermannii (bottom center), fertile plant (Daniel et al. 12084, photo by M. Nadel). Justicia secunda (bottom right), inflorescence with flowers (photo and copyright: C. Feuillet, CC BY-NC, used with permission), taken in French Guiana.