1925] Setchelh-Gardner : Melanophyceae 555 



FAMILY 14. MYRIOGLOIACEAE kuckuck 



Fronds filamentous, erect, cylindrical, solid or later tubulose, 

 central strands of larg-e colorless cells, peripheral of two sorts, free, 

 short, cortical filaments with rounded terminal cell and exserted mono- 

 siphonous filaments, with basal meristematic cells and outer cells pro- 

 vided with phaeoplasts and, consequently colored ; colorless hairs 

 absent ; terminal growth conspicuously trichothallic ; zoosporangia 

 arising at the base of the cortical filaments, unilocular ; gametangia 

 unknown. 



Kuckuck, in Oltmanns, Morph. und Biol, der Algen, ed. 2, vol. 2, 

 1922, p. 19 (by implication). Myriogloeeae Oltmanns, loc. cit. 



The family thus far is credited with a single genus, Myriogloia, 

 although it is far from certain that Mesoglaia Andersonii Farlow is 

 cogeneric with Myriodadia Scmrus Harv., as a glance at Kuckuck 's 

 figures (loc. cit., p. 22, fig. 312, 1 and 2) will indicate. The very 

 robust plants assigned to Myriodadia Scinrus Harv., M. Chorda J. 

 Ag., and 31. gramdis Howe may, or may not, belong to the same genus 

 as Mesogloia Andersonii Farlow and Myriodadia callitricha Rosenv. 

 We feel reasonably certain in referring the two last species to Myrio- 

 gloia, which is absolutely distinct from Myriodadia J. Ag., as typified 

 by M. Lovenii J. Ag., designated type of the genus, at least if one 

 credits Kuckuck 's sketches (cf. Oltmanns, 1922, p. 37, fig. 328 and 

 p. 38, fig. 329) as having been drawn from correctly determined 

 specimens. Influenced by these sketches and the various descriptions 

 (notably that of Kylin, 1907, pp. 88-90, fig. 21), we are inclined to 

 refer Myriodadia J. Ag., as limited to M. Lovenii, to the Myrio- 

 gloiaceae as here established, as a second genus, distinguished by hav- 

 ing its axis made up of a single longitudinal and persistent cellrow 

 (monosiphonous axis), whereas in Myriogloia this condition is soon 

 lost, the frond becoming polysiphonous or hollow^ below, and in the 

 thicker species {Myriodadia Sciurus, M. Chorda, and M. grandis) the 

 medullary portion is probably polysiphonous from the first (cf. 

 Kuckuck 's figure 312, 2, on p. 22 of Oltmanns, 1922) and remains 

 solid. So far as our opportunities are concerned, there is insufficient 

 material to follow out a detailed investigation and we cannot proceed 

 farther than the above suggestions. Oltmanns, however, keeps Myrio- 

 dadia (1922, p. 34) distinct and establishes a special tribe, Myrio- 

 cladieae, for it under the family Spermatoehnaceae. Spermatodinus, 

 however, has a distinct apical cell. 



