Basicladia crassa HoflFmann & Tilden 1930, p. 382 

 PI. 77, Figs. 11-13 



Thallus composed of tangled prostrate filaments giving rise to up- 

 right filaments as much as 2 cm. long; upright branches rigid, 50- 

 120/x in diameter in the distal portions, composed of thick-walled 

 coenocytic units up to 3175/i, in length, the vertical filaments some- 

 times dichotomously branched, sometimes to the second order, but 

 straight and rigid, gradually tapering toward the anterior end. 



On backs of snapping turtles in northern lakes; producing zoo- 

 spores in August. Mich., Wis. 



ORDER OEDOGONIALES 



In this order the plants are filamentous, either simple or branched, 

 and always attached, at least when young. The cells are sometimes 

 cylindrical, but usually they show a slight inflation or increase in 

 size toward the anterior end. In Oedogonium, cell division occurs 

 by the interpolation of a new section or cylindrical piece that devel- 

 ops by the stretching of a thick inner ring of material which forms 

 near the anterior end of a cell. The rupturing of the wall as the elon- 

 gation occurs leaves an external ring-like scar at the anterior end of 

 the cell. The chloroplast is a parietal reticulum containing several 

 pyrenoids. The cells are uninucleate. Asexual reproduction occurs 

 by large multiflagellate zoospores formed singly in undifferentiated 

 vegetative cells. Sexual reproduction is heterogamous. The female 

 organ (oogonium containing a single egg) is much enlarged and 

 opens by a pore or lid to permit the entrance of the antherozoid, 

 which is a small motile gamete produced either in box-like anther- 

 idial cells in filaments the same size as those which bear the oogonia, 

 or in dwarf male plants epiphytic on the female. 



There is one family, the Oedogoniaceae. Two of the three genera 

 which compose this family are well represented in the region, but 

 Oedocladium has not yet been reported. Oedocladium is a genus 

 small in number of known species. Some of them undoubtedly occur 

 here and are to be sought for in terrestrial rather than aquatic 

 habitats. 



FAMILY OEDOGONIACEAE 



Characters as described for the order. 



Special terms used in describing taxonomic features of the Oedo- 

 goniaceae will be found in the Glossary. For complete descriptions 

 of the reproductive and morphological characteristics of this family, 

 see Tiffany ( 1930 and 1937 ) . 



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