2. M. graniferum. 



Amphiroa granifera Harvey, Phyc. austr. pi. CCXXX. Syn. Cat. 1863, p. XXX. 



Ampkiroa intermedia Harvey. 



Amphiroa stellata Kutzing, Spec. Alg. 1849. 



Amphiroa similis Sonder, Bot. Zeit. 1845. 



Amphiroa setacea Kützing, Spec. Alg. 1849. 



Plants with branching, distinctly articulate fronds. Joints cylindrical up to 0,5 cm. long and 

 at the utmost 1 mm. broad. Nodes surrounded by a tuft of branches like whorls, no true whorls 

 just as in M, charoidcs. Anatomical structure of joint consists of many layers of cells all of 

 the same size, the cells of each horizontal row communicating by thin places in the thin walls. 



In the nodes the cells are very small and thick-walled. 



Fructification consists of conceptacula, that appear first on the inner side of the branches 

 but afterwards cover the whole branch. 



A. similis Sond. is only distinguished from A. granifera Harv. by its smaller size. Of 

 A. setacea Kütz. there is only a very small specimen in Kützing's herbarium. I think it probable, 

 that this plant belongs also to M. graniferum but I am not quite sure. It has the same anato- 

 mical structure as M. graniferum. 



Af. graniferum is an inhabitant of the Australian seas : the plant called Amphiroa setacea 

 was found on the coast of Peru. 



3. AI. stclligerum. 



Corallina stclligera Lamarck, Mem. du Musée II, p. 239. 



Amphiroa stelligera (Lamk.) Areschoug, Die Corallineae in Agardh's Spec. Gen. & Ord. Alg. 



1851, p. 540. 

 Amphiroa jubata Lamouroux, Hist. polypiers flex. 1S16. 

 Amphiroa interrupta Lamouroux, Hist. polypiers flex. 18 16. 

 Amphiroa verrucosa Lamouroux, Hist. polypiers flex. 18 16. 

 Amphiroa elegans Sonder, Bot. Zeit. 1845. 



Long, slender plants with branching fronds ; distinctly articulate when young, less so in 

 old plants. Branches whorl-like, very slender. Old plants often drop their calcified cortical lavet- 

 and slender branches. 



Anatomical structure of the young joints consists of many rows of cells, all of the same 

 size. In the nodes the cells are very small, thick-walled and take various shapes above all in 

 old plants, where the central layer of the joint loses its chalk and where, by subsequent divisions 

 of a layer of cells surrounding the central strand, the calcified cortical layer is throvvn off and 

 a new cortical layer formed. This process gives rise to the cup-like swellings we often see at 

 the top and base of nodes of AI. stclligerum pi. XV, fig. 9. 



Conceptacles on the branches. This species may have a very different appearance accorcling 

 to whether the cortical layer has fallen off or not. Plants that were rather bare or had only slender, 

 scattered branches were called A. jubata or A. interrupta by Lamouroux. I believe that A. 

 verrucosa is also a synonym of this species. Areschoug gives the name as a synonym of A. cha- 

 roidcs but he ackls, that he has not seen the authentic specimen. Under the name of A. verrucosa 



