UC specimens and range limits for Hydroclathrus clathratus

• Blue markers: specimen records
• Yellow marker: type locality, if present
• Red markers: endpoints of range from literature

View map from the Consortium of Pacific Northwest Herbaria

Notes: Globally distributed in warm and tropical environments. California Hydroclathrus is at the northern end of its range.

Status: This pan-tropical species is a good candidate for a phylogeographic assessment. The genus was reviewed by Kraft and Abbott (2003) in the context of descriptions of two new Hawaiian species.

Habitat: Low intertidal - mostly subtidal, on shallow reefs and in kelp forests

Life History: A heteromorphic life-history pattern with an alternation between erect, globose thalli bearing plurilocular zoidangia and prostrate thalli bearing ectocarpoid plurilocular and unilocular zoidangia. Plurizoids released from erect and prostrate thalli developed into prostrate thalli. Unizoids, however, developed into erect thalli. Prostrate thalli produced plurilocular zoidangia in long-day conditions and unilocular zoidangia in short-day conditions at 10-20°C. Germlings did not grow at 5°C (Kogame 1997).

Search Sequences in GenBank

Hydroclathrus Bory 1825

Thalli globose, hollow, increasingly fenestrate with aging, tending to rupture and form irregular, fenestrate sheet, or by repeated convolution assuming a compact, massive form. Colorless hairs grouped in shallow depressions. Plurangia formed over entire surface of younger plants.

Hydroclathrus clathratus (C. Ag.) Howe

Encoelium clathratum C. Agardh 1822a: 412. Hydroclathrus clathratus (C. Ag.) Howe 1920: 590; Setchell & Gardner 1925: 543.

Thalli irregularly globular when young, hollow, sessile by broad attachment, soon developing numerous perforations, these to 8 mm diam., later by successive convolutions and by coalescence forming compact, massive thallus to 1 m diam.; margins of perforations involute; thallus wall of small, pigmented cells; inner cells in several layers, large, colorless; hairs in small, depressed tufts in center of plurangial sori; reported to bear plurangia only in juvenile stages before perforations are formed; reproduction not observed in Calif. material.

Frequent to locally abundant, May through November, on rocks, lower intertidal to subtidal (to 6 m), Portuguese Bend (near San Pedro) and Santa Catalina I., Calif., to Baja Calif. and Ecuador. Widely distributed in tropical and subtropical seas. Type locality: S. Pacific.

Excerpt from Abbott, I. A., & Hollenberg, G. J. (1976). Marine algae of California. Stanford University Press, Stanford, California. xii [xiii] + 827 pp., 701 figs.

Notes: According to the Index Nominum Algarum, Womersley (1987: 300) lectotypified the name with a specimen from Belle-île, Brittany, France. Hamel (1937:202) recorded that Bornet thought that the provenance might have been inaccurately recorded because the shells on which the specimens grew do not occur there naturally.