undoubtedly occur in the region are included. In order to make 

 an adequate study of this interesting group, dredging and other 

 special methods of collecting would be required. Many species of 

 Chara listed by Robinson ( 1906 ) occur in the range of this area, 

 but none are specifically referred to Michigan and Wisconsin. See 

 Allen (1888-1896), Robinson (I.e.), and Groves and Bullock- 

 Webster (1924) for the taxonomy of Chara. 



Key to the Species 



1. Stems iincorticated (Ecorticata) 2 



1. Stems corticated (Corticata) .._. 3 



2. Bracts about the oogonium distinctly shorter 



than the mature fruit C Braunii 



2. Bracts about the oogonium as long as or 



longer than the mature fruit C. Schiveinitzii 



3. Cortication haplostichous (see definition above) C. canescens 



3. Cortication diplostichous or triplostichous 4 



4. Cortications diplostichous 5 



4. Cortications triplostichous 7 



5. Primary cortical cells more prominent than their secondary laterals 6 



5. Lateral cortical cells in pairs and more prominent than the primary 

 cell; posterior bracts much shorter than the 



oogonium, sometimes wanting C. vulgaris 



6. Stipulodes in a double row, the upper longer than the lower 



and persistent; bracts about the oogonium M its length C. excelsa 



6. Stipulodes in a double row but short and blunt, usually deciduous, 

 leaving scars; bracts about the oogonium sometimes a little shorter 



than the female organ but usually 6-7 times its length ^ C. contraria 



7. Leaves (branchlets) uncorticated in the internode region just 

 above the node of the stem; oogonia and antheridia on different 



leaf nodes, or sometimes on the same node -- — . — - - - 8 



7. Basal internode region of the leaves corticated; oogonia and 

 antheridia always on the same leaf node . . C fragilis 



8. Bracts about the oogonia longer than the mature fruit 9 



8. Bracts about the oogonia shorter than the mature fruit C. sejuncta 



9. Oogonia and antheridia on the same node C. elegans 



9. Oogonia and antheridia at different nodes C formosa 



Chara Braunii Gmelin 1826, p. 646 

 PL 81, Fig. 1 

 Plants bright green, slightly if at all encrusted with lime, but 

 crisp, (6)-15-20 cm. high; stem long-jointed, with a single whorl of 

 stipulodes at the node, one for each of the leaves, of which there are 

 10-12; internodes of stem and leaves entirely uncorticated; sex 

 organs monoecious, borne at the same node; oogonia 0.7-0.8 mm. 

 long, subtended by bracts which are shorter than the mature fruit, 

 cortical cells of oogonium showing 9-10 turns; antheridium small, 

 0.25-0.275 mm. in diameter. 



[ 336 ] 



