XVII. OBSERVATIONS ON RHODYMENIA. 



FREDERIC K. BUTTERS. 



History and Literature. The genus Rhodymenia was 

 founded by Greville in 1830. As originally constituted it con- 

 tained species which have since been referred to Gracilaria, 

 Gigartina, Kattymcnia, Calliblepharis and other genera. 

 Agardh (3), p. 376, states that in his Mediterranean Algae (i) 

 he transferred many species to the genera Gracilarja, Gigan- 

 tina and Kallymenia, but united Calliblepharis \\ith Rhody- 

 menia under the latter name. In 1849 Kiitzing in his Species 

 Algarum, p. 778, united the species of the genera Rhodymenia 

 and Gracilaria together with some other species under the 

 generic name Sphcero coccus. 



Agardh (2), p. 15, (3) p. 375, revised the genus Rhodymenia 

 and gave it substantially its present limits and generic characters. 

 The generic description as given by De-Toni and Levi, p. 19, 

 is as follows : Frond plane, membranaceous, dichotomous or pal- 

 mate, proliferate from the margin or surface, composed of two 

 layers ; interior cells oblong, cortical minute, rounded ; cystocarps 

 scattered throughout the frond, each within an hemispherical 

 pericarp opening by a carpostome, composed of cells, the outer 

 radiating the inner concentric ; cystocarp with a simple rounded 

 or somewhat lobed nucleus ; nucleus naked within the pericarp, 

 on a basal placenta with paniculate-branched placental fila- 

 ments sustaining the lobes ; young fertile lobes disposed radially 

 composed of articulated filaments, older obconico-rotund, bear- 

 ing numerous protospores ; tetraspores often collected into sori, 

 cruciately divided ; antheridia produced in superficial sori com- 

 posed of minute hyaline cells in a single vertical series. 



Greville spelled the name of this genus Rhodomenia. Mon- 

 tagne, p. 44, in 1839, employed this spelling in a list of Bra- 

 silian cryptogams, but in a footnote states that, in conform- 

 ity to its etymology it should be spelled Rhodymenia. J. 



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