236 



The most characteristic feature of this species is the clavate 

 shape of the branchlets. The upper part of the branchlets is 

 thickened, having for the most part no ramuli, but sometimes a 

 few and scattered ones may be found. Even the main filaments 

 are sometimes more or less clavate in their upper end, most 

 probably in such plants in which the growth begins to be slow, 

 else the main filaments taper evenly towards their summit. 



The ramuli are short and robust, about 600 n long. They 

 are upwards curved and keep nearly the same breadth from their 



base to a little above their 

 middle, tapering then rather 

 quickly and ending in an acute 

 spine composed of 3 4 super- 

 posed, small cells. Sometimes 

 the ramuli, too. taper towards 

 their base, these being thickest 

 in the middle. The cells in 

 the ramuli are mostly as long 

 as broad; in the middle of the 

 ramuli about 60 /j. long and 55^ 

 broad. At the transverse walls 

 a whorl of small cortical cells are 

 present. 



The main filaments as well 

 as the branchlets are corticated. 

 The cortex consists of alter- 

 nating series of cells : shorter, 

 oval ones above the transverse 

 walls of the large central cell 

 and longer, cylindrical ones 



between them. The first men- 

 Fig. 227. Spyridia clavata Kiitz. Part .. , , o-^nv j 



of a plant. (About 18 : 1). tloned are about 25-40 // broad 



and 45 70// long, the cylindri- 

 cal are about 6070^ long and often not more than 8 jut broad. 



Upon specimens preserved in spirit the large central cells are 

 very easily seen; in the main filaments the joints are about 2 x /2 

 times as broad as long. 



The nearly spherical tetrasporangia are seriately placed upon 

 the upper side of the ramuli near their base: sometimes the 

 tetrasporangia occur also on the lower sides of the ramuli. They 

 are tetrahedrally divided, having thick walls, their diameter 

 reaching about 50^. 



