210 Rhodora [AvGUsT 
ter might consider the figures as applicable to P. rimosa, a compari- 
son of the two plants would convince any one that the two species 
were distinct, and that Reinsch's plate fitted better to the Revere 
plant than to P. rimosa: That they belong to different genera, how- 
ever, may be open to question until the fruit of P. rimosa is known. 
‘The sporangia of the latter may prove to be intercalary, which, in the 
present arrangement of the Chroolepideae would be sufficient to 
maintain it as a distinct genus. If the sporangia prove to be the 
same as in Æcroblaste, then the latter name will have to be dropped, 
and both species placed under Piinia. 
Another Pilinia species is P. diluta Wood, F. W. Algae of the U. S., 
p.211, 1872. This has been thoroughly studied by Miss Josephine 
Tilden, Minnesota Bot. Studies, Vol. I, p. 601-635, and the conclu- 
sion that she reaches, that it is merely a stage of growth of some 
Stigeoclonium, is undoubtedly correct; but her further deduction, 
that all species of Acrodlaste and Pilinia are growth forms, is, as 
pointed out by Hazen,! unjustifiable. This appears clearly from her 
figures in Plate XXXII; the band-shaped chromatophores are very 
different from the chromatophores in Reinsch’s and Kützing's figures, 
where they occupy the whole of the thick-walled cell. 
A third species has been added to the genus, P. maritima (Kjellm.) 
Rosenv. to include Chaetophora maritima and C. pellicula, both of 
Kjellman. Both of these species have abundant hairs, the presence 
of which is characteristic of the subfamily Chaetophoreae, as defined 
by Wille in Engler & Prantl. Rosenvinge figures terminal sporangia, 
whose presence is characteristic of the Chroolepideae, their absence 
of the Chaetophoreae. It would appear that some new character 
must be found, if these subfamilies are to be kept distinct; at any 
rate Kjellman's C. maritima, with abundant hairs and smooth globu- 
lar thallus, can hardly be placed in the genus 7/xza as here under- 
stood. 
THE GENUS PonPHYRA is represented in Farlow's Marine Algae of 
New England by only one species, P. /aciniata ( Lightf.) Ag., although 
the author notes that Z. /eucosticta Thuret is to be expected. In the 
list given by the writer in Rropona, Vol. II, p. 41, four species were 
'The Ulothrichaceae and Chaetophoraceae of the U. S., Mem. Torr. Bot. Club, 
Vol. XI, p. 200, 1902. 
? Rosenvinge, Grénlands Havalger, p. 932, 1893. 
