1925 ] Setchell-Gardner: Melanophyceae 517 



even traces of deciduous ones. Consequently we do not feel certain 

 of anj- constant difference among' these three genera, viz., Punctaria., 

 Homoeostroma and Desmotrichum. We also do not find any definite 

 distinctions to separate Shuh's Rhadinocladia (1900, pp. Ill, 112) 

 from the simpler Desmotrichums (cf. especially Kylin, 1907, pp. 

 66-68), nor are we able to distinguish satisfactorily Kuetzing 's Diplo- 

 stromium (1843, p. 298) while J. G. Agardh's Nematophloea (1896, 

 p. 12), if Kuetzing's figure (1856, pi. 45, I) is to be considered typical, 

 seems to have nothing to distinguish it from Kuetzing 's Phycolapathum 

 (excluding synonymy of type species, pro parte) and Punctaria. 

 Phycolapathum Kuetzing (1843, p. 299, pi. 24, II) is founded on 

 Greville's Punctaria latifolia, although Laminaria debilis Ag. is 

 quoted, possibly erroneously, as a synonym. The plate of Kuetzing 

 represents a Punctaria. We have, therefore adopted the name Punc- 

 taria for all of our species, but we have seen none of the slender 

 Desmotrichum type on our coast, Punctaria has received the sanction 

 of the International Botanical Congress (Rules, 1912, p. 76) for the 

 generic name. 



Key to the Species 



1. Fronds with numerous marginal crenulate lobes 2 



1. Fronds with entire, smooth or undulate or coarsely ruffled margins 3 



2 Fronds large, up to 50 cm. long, chartaceous, composed of 6-7 layers 



of cells 6. P. chartacea (p. 521) 



2. Fronds small, 10 cm. long, composed of 4 layers of cells. .4. P. lobata (p. 519) 

 3. Fronds broadly expanded, up to 30 cm. broad, very fragile. .7. P. expansa (p. 521) 



3. Fronds narrower, up to 10 cm. broad 4 



4. Fronds narrowly linear, distinctly stipitate, smooth, entire 5 



4. Fronds irregular, more or less broadly expanded, obscurely stipitate, 



with undulate or ruffled margins 6 



5. Fronds epiphytic, base broadly cuneate, apex not laciniate..l. P. hesperia (p. 517) 

 5. Fronds saxicolous, long stipitate, base narrowly cuneate, the apex deeply 



laciniate 2. P. fissilis (p. 518) 



6. Fronds with undulate, much ruffled margins. .5. P. occidentalis (p. 520) 

 6. Fronds with smooth or slightly undulate margins... 3. P. latifolia (p. 519) 



1. Punctaria hesperia S. and G. 



Plate 37, fig. 30, and plate 19, fig. 18 



Fronds 1.5-2.5 cm. high, 5-10 mm. wide, solitary or in small 

 clusters, tapering at the base to a very short stipe and to a blunt apex, 

 35-50/* (up to 80jLt) thick, composed of 4-6 layers of cells, those of the 

 two middle layers much larger than those of the cortical layer ; cortical 

 cells thin walled, 4-5 sided in surface view, 18-22/* diam. containing 

 numerous parietal disk-shaped or small band-shaped chromatophores, 



