281 



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 Sarcomenui minlata 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" as to the systematic position of Sarcouienia minutta 

 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 minlata 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. f 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 \h 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. 



Tlie anatomical structure of Sarcomenia miniata may be supposed 

 to be sufficiently known by the descriptions of Agardh l and the 

 drawings of Grunow.§ 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. 



* Grunow, A., Algen der Novara-Reise, pj). 92-93. 



+ Kecorded by Miss Barton in Journ. Bot. 1896, p. 198. 



\ Agardh, J. G., Sj^ecies, Genera, et Ordines AUjarum, vol. ii. p. 1'2G0. 



§ Grunow, I. c. plate xi. 



Journal of Botany. — Vol. 34. [July, 189(5.] u 



