120 



Dansk Botanisk Arkiv, Bd. 3. Nr. 1. 



Found in several places at St. Jan in the sound between this island 

 and St. Thomas where it seems to be common. 



3. Wrangelia pcnicillata C. Ag. 



Agardh, C, Spec. Alg. II, p. 138. Agardh, J., Spec. Alg. II, pars III, 

 p. 708; Epicrisis, p. 623. Derbes et Solier, Memoire, p. 71, pi. 18, figs. 6 — 8. 

 KüTziNG, Spec, p. 664. Harvey, Nereis Bor. -Am., Part 11, p. 143, tab. 34 B. 

 BoRNET et Thuret, Notes algologiques, Fasc. II, 1880, p. 183. pi. 48. Zer- 

 lang, O. E., Entwicklungsgesch, Untersuch, über die Florideen-Gatt. Wran- 

 gelia und Naccaria (Flora, 47, 1889, p. 371). 



G/iffithsia penicillata Agardh, Systema Alg., p. 143. 



Dasya spinella Duby, Second memoire sur le groupe des Céramiées, 

 p. 13, tab. II, figs. 3, 4, 5 and tab. Ill, ligs. 1, 2. 



In the West Indian seas this plant attains a great size especially 



when it is growing in deep water. 

 Several of the specimens reach a 

 height of 20 cm or even more. 

 The specimens growing in shal- 

 low water are smaller and more 

 robust and more like the Euro- 

 pean specimens while the speci- 

 mens from deep water are more 

 flabby, thinner and in all re- 

 spects more elongated. As to the 

 American form see Harvey, 1. c, 

 where a description and good 

 figures of this plant are found. 

 Zerlang has 1. c. given a very detailed description of the 

 development and structure of this plant to which the reader is 

 referred. I shall only mention briefly that the main filaments in 

 an early stage of development become bare at their base while 

 higher up they carry the verticillate branchlets at each joint. 

 From each of these whorls a smaller branch issues and these 

 branches are regularly alternating. Some of these branches grow 

 out mto long branches and serve to form the ramification of the 

 thallus, most of them in the sterile plant soon die away and fall 

 off; in the fertile plant, on the other hand, they carry the organs 

 of fertilization and last longer. The branchlets are subdichoto- 

 mously branched, thin and soft. At the apices of the branches 

 the branchlets are bent upwards and more or less cover the 

 growing point of the branch, giving all the short branches a 

 penicillate appearance. The ends of the filaments in the ramuli 

 are blunt. 



Fig. 131. Wrangelia penicillata C. Ag. 



Part of a plant with tetrasporangia. 



(About 200 : 1). 



