362 



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



The life-histpry of this plant has been studied very minutely 

 by OsTERHOUT. The following short description is based partly upon 

 his description, partly upon my own observations. 



Agardhiella grows at the islands in more sheltered places in 

 shallow water and likes localities with sandy or muddy bottom sprink- 

 led with stones. To these the plant is fastened by means of a disc 

 from which often several erect stems arise. These are much branched 



Fig. 355. Agardhiella tenera (J. Ag.) Schmilz. 

 a, trHnsver.se section of the thallus. b, longitudinal section of the thallus. 



{a, about 80:1; b, 45; 1). 



in all directions, the plant forming in this way small highly branched 

 bushes up to about a foot high. When growing in shaded places 

 their colour is a clear rosy-red, in strong light on the other hand 

 they assume a more yellowish-brown tinge. 



The summit of the plant looks like several densely placed fila- 

 ments. According to Osterhout's examination and as far as I have 

 seen there is nevertheless a central filament and lateral filaments 

 extending from it. 



Transverse and longitudinal sections of the thallus (Fig. 355) 

 show that there is in the middle a very loose tissue consisting 

 of long much curved and bent filaments, now and then ramified 

 and running between each other. In the fully developed thallus 

 this medullary tissue is so loose that we may rightly say that 

 there is, in the interior of the thallus, a cylindrical cavity filled 

 with sap through which the filaments run. The peripheral tissue 

 is firmer, consisting innermost of one or two layers of large, 

 roundish-polygonal cells covered by a layer of small epidermal cells. 



