147 



Helminthocladia J. Agaidh. 

 1. Holmiuthoclcadia imrpiirea (Harv.) J. Ag. 



J. Agaiclli, Spec. II, p. 414, III, p. oOG: Flora Danica lab. li()9'.) ; Sclimitz, CIiiumato|)lioreii lier Alf,'cii, p. (53 

 fig. 11 12. 



Mcsoj/loia purpurea Harvey in Hooiier Hrit. Flora II, 1833, p. 386. 



Nemalion piirpiircum Cliaiiv. ; Harve:', Pliyc. Hrit. PI. 161; Kiitzing, Tab. pliyc. Hi. Hand I'l. (12 c, d. 



The struclure of the frond is somewhat similar to that of Nemalion nmlli/idum, 

 bill the assimilative filaments are composed of larger cells, of which the terminal 

 ones are the largest (fig. 71). These terminal 

 cells bear no hairs, and these organs are 

 upon the whole rare in the older parts of 

 the plants, while they occur fairly abun- 

 dantly in the younger parts. They are 

 given otf from thinner branches not reach- 

 ing the surface of the frond and are partly 

 terminal, partly lateral; they have the same 

 structure as other similar hairs, arc fairly 

 thick and attain a considerable length (fig. 

 71 A, B). Besides the hair a little cell with 

 fairly dense contents is visible; such cells 

 are also to be found in the older parts of 

 the frond without hairs. The chromato- 

 phores which are particularly large and 

 well developed in the terminal club-shaped 

 cells, contain as shown by Schmitz (I.e.) a 

 large central pyrenoid which in some cases 

 was readily visible as a dense body, while 

 in other cases they conveyed rather the 

 impression of being vacuolar cavities like 

 those stated for Nemalion by Wolfe (figs. 

 71 A, 12 A, B). 



The antheridia form dense, often hemi- 

 spherical clusters at the end of the assimila- 

 tive filaments. The outermost cells are then 

 small and bear a number of short much branched antheridia-bearing branchlets. 

 These branchlets are shorter than in Nemalion and Helminthora and their joints 

 are often nearly globular (fig. 72 A — C). In some cases a number of globular cells 

 were found crowded together at the upper end of the last cells in the assimilative 

 filaments (fig. 72 E, F). These cells, which were larger than the antheridia and 

 contained a thin chiomatophore, might be suggestive of monosporangia ; they were 

 however certainly no such organs but probably only checked antheridial branches, 



19* 



; Fig.^71. 



Halminthocladiaipurpiirea. A, end of assimilative fila- 

 ment with young hair. B, similar witli base of hair. 

 C, young l-celled carpogenic tihiment. D, assimilative 

 filaments with antheridia and carpogenic filament. £, 

 end of branch with a terminal 4-celIed and a lateral 

 2-celled carpogenic filament. F. carpogenic branch 

 in stage of fertilization. :S;)0:1. 



