Indian Ocean Catalogue

PHLOIOCAULON SUHRII

Suhr (1834: 738--739) considered an alga from Algoa Bay, South Africa, to be conspecific with Fucus squamulosus Turner (1808--1809: 148--149, pl. 128). In comparing the two entities, Suhr wrote: ``Ich halte beides für eine Art, und die Abbildung des berühmten Engländers, dem nicht mehr als ein einziges Exemplar vorgekommen, nur für eine besonders grosse Pflanze, wesswegen ich jenen Namen beibehalten habe, obgleich ich ihn sonst nicht besonders passend finde''. [I consider both as one species, and the illustration of the famous Englishman, who had only a single specimen at hand, as just an especially large plant, which is why I have retained that name, although I do not find it especially suitable.] The binomial Sphacelaria squamulosa, therefore, should be accredited to (Turner) Suhr and not, as all subsequent authors have done, considered applicable to a new species described by Suhr. The type specimen was seen by Turner in the Banks Herbarium, where it had come from the Aublet Herbarium, without indication of provenance. Aublet is chiefly remembered for his botanical exploration of French Guiana, but he is known to have collected also in Dominica, Haiti, and Mauritius.

Kützing (1847a: 54), in transferring Suhr's plant to his recently established genus Chaetopteris, made the combination C. squamulosa, citing ``Sphacellaria squamulosa Suhr'' without mentioning Turner. Later, Kützing (1849: 468) included Fucus squamulosus Turner, with a query, as a possible synonym. Meanwhile, the species had been treated by J. Agardh (1848b: 40--41), who explicitly excluded the Turner species, pointing out three features shown in Turner's illustration that do not agree with Suhr's plant, namely, ``radix fibrosa'' (hapteroid holdfast), spines on the upper part of the branches, and small scales on the lower part of the stem. He accordingly described the species anew, as Chaetopteris suhrii J. Agardh.

Geyler (1866: 509--511, 529--530) established the genus Phloiocaulon to accommodate the South African plant. In making the combination P. squamulosum, Geyler cited Chaetopteris squamulosa Kützing as the basionym and C. suhrii J. Agardh as a synonym. The authorship of Geyler's combination has been cited variously and always erroneously: Suhr alone (as by Reinke, 1890: 213; 1891: 28); Geyler alone (as by Barton, 1893: 111); and (Suhr) Geyler (as by De Toni, 1895b: 519). If confirmation could be obtained for Suhr's opinion that his plant is conspecific with Fucus squamulosus, the authorship of P. squamulosum could be corrected to (Turner) Geyler, since Geyler did not explicitly exclude Turner from the synonymy of this name. Papenfuss (manuscript) sought but failed to find the type specimen of Fucus squamulosus at BM in 1964. He noted, ``The drawing by Turner of Fucus squamulosus shows spinelike processes and a thick axis, features which suggest a plant different from Phloeocaulon''. Moreover, the hapteroid holdfast shown by Turner contrasts with the parenchymatous discoid base of the South African plant. Through the courtesy of Dr. Per Lassen, Curator of the Herbarium at Lund (LD), the type sheet of Chaetopteris suhrii was sent on loan to Berkeley. The sheet, labeled in J. Agardh's hand ``Chaetopteris Suhrii J.Ag. Sp.'', bears two mounted specimens (no. 45922) labeled ``Sphacelaria squamulosa Suhr Cap.b.sp.'', in Suhr's hand, and a packet (no. 45923) labeled ``Sphacelaria squamulosa Suhr Algoa bay.'', in Suhr's hand, and enclosing a small branch. The three specimens are clearly representative of the alga currently called Phloiocaulon squamulosum. As lectotype, I choose the specimen in the packet. Duplicates are housed at KIEL and at S according to Papenfuss (notes).

In view of the differences between Turner's illustration of Fucus squamulosus and the alga currently called Phloiocaulon squamulosum and in the absence of a type specimen to clarify the situation, it seems best to adopt J. Agardh's Chaetopteris suhrii as the earliest name for this species, as P. suhrii (J. Agardh) P. Silva.