300 



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



Subfam. 6. Bostrychieæ. 

 Bostrychia Montagne. 



1. Bostrychia tenelia (Vahl) J. Ag. 



Agardh, J., Spec. Alg., vol. II, p. III, p. 869. Analecta Algologica, cent. 

 IV, 1897, p. 83. Falkenberg, P., Rhodomelaceen, p. 515. 



Fucus tenellus Vahl, Endeel kryptogamiske Planter fra St. Croix (Skriv- 

 ter af Naturh. Selskab, 5te Bd., 2 Hefte, Kiobenhavn 1802, p. 45). 



For more synonyms compare: De-Toni Sylloge Alg., Vol. IV, p. 1162. 



Bostrychia tenella (Fig. 299) occurs as a rather common epi- 

 phyte upon the roots of the mangroves, or it grows upon stones 



Fig. 299. Bostrychia tenella (Vahl) J. Ag. Part of a plant. (About 8:1.) 



and rocks near or in shaded locaHties somewhat above the sur- 

 face of the sea. 



It has 6 to 8 pericentral cells, 8 in the older main stems, 

 fewer upwards in the branches; in the branchlets the number of 

 pericentral cells decreases more and more, making an even transi- 

 tion to the often long monosiphonous summits of these. 



The pericentral cells are in an early stage of development 

 divided by horizontal walls into two cells. From the outer sides 

 of these cells, as described by Falkenberg, cells are cut off from 

 which the cortical layer originates. This makes a thick cover 

 upon the main stem (Fig. 300), thinner upon the side-branches, 

 and disappears gradually upwards, the thinner branchlets being 

 quite uncovered. 



