KUNGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 6 1 . N:0 I I . 47 



Lessonia Bory. 



L. flavicans Bory; Skottsb. Ant. Meeresalg. I p. 73. 



In the sublitoral region. — Fuegia: Slogget Bay, drifted (St. 47 b, 16. 3. 



09, sp.). Falkland Islands: Port William, 5 m, stones and shells (St. 12, 



10. 2. 08); near Hooker's Point, drifted (Nov. 07); West Falkl., Halfway Cove, 8 m, 

 fragments of leaves (St. 5, 25. 11. 07). 



The enormous stem of L. flavicans, which resembles the trunk of a small tree, 

 is often formed by the primary stipes, but sometimes replaced b 3' a branch. The 

 leaves are rather thin, of a light brown colour, large and broad, their margins pro- 

 vided with large, distant teeth. My material does not possess any mucilage ducts. 

 According to Hooker and Harvey such ducts are present in both flavicans (fusce- 

 scens) and ovala, although more numerous in the former, as well as in nigrescens. 

 Howe, Mar. Alg. of Peru p. 59, has misunderstood this passage; Hooker compares 

 flavicans + nigrescens with ovala, not flavicans with nigrescens. 



For the moment I shall leave aside the question of the presence or absence 

 of mucilaginous ducts. There is one »L. flavicans» and one »L. nigrescens* , which 

 seem to differ in so many respects that they represent two species. My L. flavicans 

 from the Falkland Islands is undoubtedly the species treated at some length by 

 Hooker in Flora Antarctica under the younger name fuscescens, my L. nigrescens 

 from the same place is also Hooker's nigrescens. That the 1 ätter (and the so-called 

 L. Suhrii) should differ from the former (and from L. laminarioides) in possessing a 

 »callum radicalem magnum et in sicco durissimum», while the others have »radices 

 distinctae», as says Areschoug, Obs. phycol. V: 2 p. 10, is certainly not true. All 

 Lessonias that I have seen are provided with a holdfast composed of branched 

 hapteres. 



Returning to the occurrence of mucilage in glands and ducts, it is evident that 

 the plant named L. flavicans, is, in this respect, heterogeneous. Bory, Voy. Coquille 

 p. 77 made the following description of the leaves: »leur surface a quelque chose de 

 chagriné quand on les a plongées dans l'eau, ce qui vient d'un multitude de petites 

 bulles qui se boursoufflent dans 1'épiderme, sans que nous ayons pu reconnaitre si 

 elles contiennent de Fair, de 1'eau, ou quelque mucosité». I guess that these »bulles» 

 were mucilage glands. They were present in Hooker's material, while mine from 

 1902 was less uniform and the present specimens lack them. Are there two different 

 species? I hardly think so: the use of this character for the separation of species, 

 otherwise quite identical, does not appear very promising. 



Distribution: Subant. Amer., Falkl., Kerg., Heard I. — Drifted pieces have been 

 observed along the coast of S. Georgia, where according to my experience this plant 

 does not grow. Regarding the variety linearis Reinsch, see under Ascoseira. 



L. nigrescens Bory; Skottsb. Ant. Meeresalg. I p. 69. 



In his work on Peruvian marine algae, Howe remarks that among the speci- 

 mens examined by him there are some with and others without mucilage ducts but 



