Electronic Flora of South Australia Species Fact Sheet

Sporochnus stylosus Harvey 1855: 216, pl. 109B.

Phylum Phaeophyta – Order Sporochnales

Selected citations: Lindauer et al. 1961: 241, fig. 58.

Thallus (Fig. 99B) medium brown, 12–30 cm long, much branched with one to several slender percurrent axes bearing irregularly and radially short or long laterals 2–10 mm apart, each lateral with an apical tuft of assimilatory filaments; attachment by a small, discoid, rhizoidal holdfast 1–3 mm across; epilithic. Growth apical, with a convex branch meristem surmounted by a tuft of trichothallic filaments 2–3 mm long, each with a meristem 5–8 cells above their base, 18–26 µm in diameter above with cells L/B (2–) 3–4. Fronds (Fig. 101A) slender, terete, 500–800 µm in diameter in lower axes, decreasing to 300–500 µm near apices, with the determinate branchlets 3–10 mm long, and 150–250 µm in diameter when sterile.

Structure haplostichous and pseudoparenchymatous, with a medulla of elongate cells and a single- layered, smooth-surfaced cortex of cells (4–) 8–10 µm across and L/B 1–2.

Reproduction: Sporangial receptacles (Fig. 101A) elongate, (1–) 2–6 mm long and (300–) 400–600 µm in diameter, always with a sterile apex 1–2 µm long between the receptacle and the assimilatory tuft, with a short or no sterile region at the base of the determinate lateral. Paraphyses (Fig. 10IB) 80–160 and 4–6 cells long, simple, the larger terminal cell pyriform and 12–18 µm in diameter, with the lower cells bearing lateral, clavate, unilocular sporangia 30–45 µm long and 8–12 µ in diameter.

Gametophyte unknown.

Type from "Otago Harbour and Foveaux Straits", New Zealand (Lyall); in TCD or BM (ex K). Lectotype to be selected.


Distribution map based
on current data relating to
specimens held in the
State Herbarium of SA

Distribution: New Zealand. Ecuador?

In southern Australia, known from Bridport, Tas., drift ( Womersley & Parsons, 6.xi.1982; ADU, A54539); Bluestone Bay, Freycinet Pen., Tas., 6 m deep (Brown, McGeary & Womersley, 4.xi.1982; ADU, A56265); and Fluted Cape, Bruny I., Tas., 7–10 m deep (Shepherd, 10.ii.1972; ADU, A41446).

Taxonomic notes: This New Zealand species occurs in northern and south-eastern Tasmania where the above collections correspond well. There is little apparent difference from S. rostratus Taylor (1945, p. 106, pl. 2 figs 12–17, pl. 17 fig. 1) from Ecuador, which Lindauer et al. (1961, p. 241) include under S. stylosus.

S. stylosus is unusual and distinctive as a species of Sporochnus in having a sterile "style" between the receptacle and the tuft of assimilatory hairs.

References:

LINDAUER, V.W., CHAPMAN, V.J. & AIKEN, M. (1961). The marine algae of New Zealand. II. Phaeophyceae. Nova Hedwigia 3, 129–350, Plates 57–97.

TAYLOR, W.R. (1945). Pacific marine algae of the Allan Hancock Expeditions to the Galapagos Islands. Allan Hancock Pacific Expeditions 12, 1–528.

The Marine Benthic Flora of Southern Australia Part II complete list of references.

Author: H.B.S. Womersley

Publication: Womersley, H.B.S. (14 December, 1987)
The Marine Benthic Flora of Southern Australia
Part II
©Board of the Botanic Gardens and State Herbarium, Government of South Australia


Illustrations in Womersley Part II, 1997: FIGS 99B, 101A,B.

Figure 99 image

Figure 99   enlarge

Fig. 99. A. Sporochnema tomentosum (ADU, A38180, holotype). B. Sporochnus stylosus (ADU, A41446). C. Sporochnus apodus (ADU, A32938). D. Sporochnus comosus (ADU, A30831).

Figure 101 image

Figure 101   enlarge

Fig. 101. A,B. Sporochnus stylosus (ADU, A56265). A. Branch with fertile laterals with sterile regions between sporangial receptacles and apical tufts. B. Paraphyses with unilocular sporangia. C–E. Sporochnus apodus (ADU, A16396). C. A long lateral branch with short, completely fertile, branchlets. D. Sporangial receptacles extending from assimilatory tufts to parent branch. E. Paraphyses with unilocular sporangia. F–H. Sporochnus comosus, typical form (ADU, A16397). F. Branches with shortly-pedicellate sporangial receptacles. G. Sporangial receptacles with apical tufts and short, sterile pedicels. H. Paraphyses and unilocular sporangia. I,J. Sporochnus comosus, with elongate sporangial receptacles (ADU, A42542). I. Branches with shortly-pedicellate sporangial receptacles. J. Sporangial receptacles with apical tufts and short, sterile, pedicels.


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