Morphological and taxonomic relationships among branched, ligulate members of the genus Desmarestia (Phaeophyceae, Desmarestiales), with particular reference to South African D. firma

Abstract

An examination is made of the reproductive anatomy and the morphology of branched, ligulate members of the genus Desmarestia from worldwide localities. Entities from southern Africa, New Zealand, South America, Gough Island, northwestern America, and Europe show varying degrees of morphological overlap, but all possess sporangia similar in size and shape to, and scattered among, the vegetative cortical cells. Specimens from Signy Island (South Orkneys) have sporangia subtended by stalk cells, interspersed with sterile paraphyses, and arranged in a palisadelike sorus (Antarctic type). The taxonomic implications of these findings are discussed. The New Zealand and Gough entities are referred to D. ligulata (Stackhouse) Lamouroux and the name D. firma (C.Ag.) Skottsb. is retained for the southern African entity.

Ligulate Desmarestia (Desmarestiales, Phaeophyceae) revisited: D. japonica sp. nov. and D. dudresnayi differ from D. ligulata

“…Lamouroux, is a perennial species which was described from Europe and occurs in the Arctic and in cold-temperate regions of the Northern Hemisphere (Lamouroux 1824(Lamouroux , L€ uning 1990. Morphology and ontogeny of sporophytes (Chapman 1972a,b, Anderson 1985, Stolpe et al 1991, Wiencke et al 1995, sporangial type (Moe and Silva 1977, 1981, 1989, Anderson 1985, dioecism versus monoecism of gametophytes (Anderson 1982, Peters and M€ uller 1986, Ramirez et al 1986, Ramirez and Peters 1992, temperature tolerance of gametophytes Breeman 1992, 1993), and nuclear ribosomal ITS sequence data (van Oppen et al 1993, Peters et al 1997, 2000 have been utilized to study the taxonomy, phylogeny, and biogeography of Desmarestia and the related monotypic genera Arthrocladia Duby, Himantothallus Skottsberg, and Phaeurus Skottsberg. Peters et al (1997) hypothesized that Desmarestia originated in the Southern Hemisphere, possibly in high latitudes, and subsequently migrated to the Northern Hemisphere.…”

Temperature requirements of growth and temperature tolerance of macroalgae endemic to the Antarctic Region

“…Sources: Papenfuss (1964), Zaneveld (1966Zaneveld ( , 1968, Neushul (1968), Simons (19?6), Drew (19?7), Lamb & Zimmerman (1 g?? ), Seagrief (1984), Anderson (1985), Fletcher (198? ), Ricker (1987), Womersley (1987 + 15.5 to +20.0 winter temperatures, allowing sufficient growth for the most temperature-sensitive phase in the life-cycle of a given alga.…”

“…is difficult to trace due to taxonomic and identification problems. It is now generally recognized that the members of this species group, which are distributed in cold and temperate waters of both hemispheres (Table 3), cannot be distinguished solely by vegetative characters (Anderson 1985, Ramirez et al 1986). The populations of ligulate Desmarestia sp.…”

“…north and south of the Antarctic convergence are probably not conspecific and differ e.g. in sporangium type (Moe & Silva 1977, Anderson 1985. The Antarctic entity cannot occur north of areas with winter temperatures much higher than 5 "C as this would inhibit sporophytic growth (Fig.…”

Desmarestia japonica subsp. angustifolia (Desmarestiales, Phaeophyceae), a new subspecies from Korea

“…Individuals with morphotype 2 were found only on the east coast of Korea near Gangneung. Anderson (1985) used the branching patterns as a key characteristic in distinguishing Desmarestia species. Moreover, the branch morphology of Desmarestia species was used to typify D. firma (Anderson 1985; overall length, primary blade length and maximum primary blade width, maximum secondary blade length, and maximum secondary blade width).…”