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NOTES ON SARCOMENIA MINIATA Ag. By Anna Weber van Bosse. (Plate 359.)
During a trip to South Africa I was fortunate enough to collect at Plettenberg Bay, Cape Colony, a tuft of Sarcomenia miniata Ag. bearing many stichidia with tetraspores. I owe to the kindness of Miss Barton two dried specimens of the same plant bearing cysto- carps, one of which had also two antheridia. Latterly doubts have been expressed[1] as to the systematic position of Sarcomenia miniata and some other species of this genus. I think therefore that an accurate description of the cystocarps and antheridia of this plant may be useful to future students who occupy themselves with this genus.
Sarcomenia miniata was only known from the Atlantic Ocean, and was collected at Cadiz by Cabrera ; therefore I was much sur- prised to find it on the south coast of South Africa, and felt at first some doubt about the identity of both plants.[2] On comparing my plantlets with authentic material, kindly lent to me by Major Reinbold, I felt convinced, however, that Sarcomenia miniata was indeed the right name for this South African species. It was collected on rocks a little above low-water mark, where the sea was coming in with heavy rollers, and big waves were breaking on the rocks continually. I mention this because I think that agents of this kind have a great influence on the external habit of seaweeds, and should not be passed over in silence.
The plantlets grow in subglobose tufts. Now and then a single tuft exceeded the length of 1½ or 2 in. mentioned by Agardh. I saw several creeping branches emitting fronds from their dorsal side, and with rootlets growing out from the cortical cells. The length of the cells was generally subequal or only little longer than their diameter, but in a few branches the cells were decidedly longer, twice or even thrice their diameter. At the base of a strong plantlet the lower cells were entirely covered by a layer of thread-like cortical cells that had sprung from the pericentral tubes. This.was, however, not the case with fronds that had arisen from creeping filaments ; these were bare to the very base. The strong plantlet was evidently trying to fasten itself better to the soil ; the fact struck me, as Sarcomenia miniata is said to be always ecorticated.
The anatomical structure of Sarcomenia miniata may be supposed to be sufficiently known by the descriptions of Agardh[3] and the drawings of Grunow.[4] The thallus consists of one central tube surrounded by four pericentral ones, two of these latter being
furnished with a row of smaller cortical cells along their outer side.
Journal of Botany.— Vol. 34. [July, 1896.] U
