Udotea palmetta Decaisne, 1842: 105

Coppejans, Eric, Leliaert, Frederik, Verbruggen, Heroen, de Clerck, Olivier, Schils, Tom, de Vriese, Thomas & Marie, Daniel, 2004, The marine green and brown algae of Rodrigues (Mauritius, Indian Ocean), Journal of Natural History 38 (23), pp. 2959-3020 : 2995

* Udotea palmetta Decaisne, 1842: 105

( figures 22–24 )

References: Gepp and Gepp, 1911: 108–110, 122–124, pl. 1, figure 11 ; Jaasund, 1976: 29, figure 58.

Type locality. Not specified .

Vouchers. HEC 14715 (zF), 21 September 2001, Petite Butte (s.s. 23) ; HEC 14775 (zF), 25 September 2001, Passe Grand Bassin (s.s. 2) ; HEC 14817 (zF), 27 September 2001, Ile Hermitage (s.s. 18) .

Ecology. Mostly on silty sand bottom of the subtidal, from low water mark down to 0.5 m deep.

Distribution. Amirante Islands, Cargados Carajos, Mauritius ( Børgesen, 1940: 59; 1948: 34–35), Persian Gulf, Rodrigues (this paper), Seychelles, Tanzania, Yemen.

Notes. (1) Udotea palmetta is morphologically very similar to U. indica A. Gepp and E. Gepp. Anatomically they are distinguished by the morphology of the lateral appendages of the flabellum filaments. These are blunt in the latter and acute in the former. In U. orientalis these filaments have no appendages at all. (2) One collection (HEC 14817) is fertile and carries numerous dark green gametocysts in the middle ( figure 23 ) and marginal ( figure 24 ) parts of the whitish flabellum. (3) The fully grown specimens are very large when compared to those from Kenya and Tanzania, but they still agree with the original description. The stipe is up to 4 cm long, the flabellum 10 (but up to 15) cm long and 14 cm broad.

Figures

FIGS 19–24. Chlorophyta. (19) Caulerpa nummularia, proliferating from primary, peltate assimilator (HEC 14609 p.p.). (20) Rhipidosiphon javensis (HEC 14763). (21) Udotea sp. (HEC 14759). (22–24) Udotea palmetta (HEC 14817): (22) general morphology of large, fertile specimen; (23) gametangia growing from the blade surface; (24) gametangia growing from the blade margin. Scale bars: 2 mm (19, 20); 1 cm (21, 22); 1 mm (23); 500 mm (24).

FIGS 7–13. Caulerpa brachypus, variation in the general morphology and margin structure of the assimilators. (7) Large growth form collected in grooves between bumps of coral rubble, frequently branching and with secondary stolons (HEC 14867). (8) Intermediately large growth form with wide assimilators (HEC 14769). (9) Intermediately large growth form with relatively narrow assimilators (HEC 14656a). (10) Typical specimen with simple or scarcely branched assimilators (HEC 14612). (11) Assimilator with smooth margin (HEC 14612). (12) Assimilator with coarsely dentate margin (HEC 14656a). (13) Assimilator with densely dentate margin (HEC 14718). Scale bars: 2 cm (7–10); 1 mm (11–13).