Hydroclathrus clathratus (C. Agardh) M.A. Howe (1920: 590)

Liao, Lawrence M., Belleza, Dominic Franco C. & Geraldino, Paul John L., 2013, Marine algae of the Sulu Sea Islands, Philippines II: annotated list of the brown seaweeds (Phaeophyceae) from the Cuyo Islands, Phytotaxa 152 (1), pp. 1-17 : 11

Hydroclathrus clathratus (C. Agardh) M.A. Howe (1920: 590)

Basionym: Encoelium clathratum C. Agardh (1823: 412)

Type:—Belle Isle, France.

Remarks:—Arguably, this is one of most conspicuous brown algal species in the country when in season, having been reported from every island visited by botanists. This is also one of the earliest reported Philippine seaweed species by Blanco (1837) under the misapplied name Ulva reticulata Forsskål (1775: 187) due to its net-like appearance. The latter is a valid species of green alga also commonly encountered in many tropical localities.

The lectotype locality is indicated as Belle Isle in Brittany, France. This is quite likely in error as suggested by Silva et al. (1996). This species is ubiquitous in many tropical and warm temperate regions around the world including the Mediterranean. There has been no recent record from the Atlantic coast of France (i.e., Brittany) and points north along the English Channel .

Materials examined:—78EM-13 (48 to 50).

* Hydroclathrus tenuis Tseng & B. Lu (1983: 185)

Type:— Hainan Island, southern China.

Remarks:—This species was described based on distinctive anatomical and reproductive features. However, the materials from Cuyo are easily distinguished from its close congener by its very fine and fragile branches (1–2 mm diameter) created from the numerous perforations that are found throughout the thallus. Huisman et al. (2007) cautioned that young plants of Hydroclathrus resemble the closely related genus Colpomenia which are saccate, convoluted and hollow throughout its lifespan. When plants of Hydroclathrus mature, they become convoluted and show the characteristic perforations on their thalli. The different species of Hydroclathrus develop these perforations and are distinguished from one another by details of their anatomy and on the size of the branches lining those perforations.

Material examined:— MSD16528, north of Cuyo , Palawan, 30 April 1958, leg. E. G. Meñez, deposited at B. P. Bishop Museum .