630 MINNESOTA BOTANICAL STUDIES. 



With this fact in view it is not difficult to account for some of 

 the "new species" among the genera related to Stigeoclonium. 

 In particular it is believed that Pilinia diluta Wood, Chaetoph- 

 ora pellicula Kjellman, and perhaps some of the species of 

 Endoclonium are forms of Stigeoclonium. Stigeoclonium 

 pygmaeum of Hansgirg (I) approaches the Belief onte plant 

 more nearly than any other species in that it is coated with 

 lime, its branches sometimes 2-3 approximate and its trichomes 

 altogether similar in character. But this is an epiphyte or 

 endophyte living on Ranunculus, Lemna, and other aquatic 

 plants. 



This belief is strengthened by various observations found in 

 descriptions of this genus. Dr. Wood (ii. 206. PI. 19, fig. I.) 

 himself states that a Stigeoclonium, which he watched for 

 several seasons, in its earlier state "appears at times to 

 possess the characters of a young Chaetophora, forming a 

 small gelatinous base out of which the threads soon escape as 

 they lengthen." His figure might well be taken as a repre- 

 sentation of a Pilinia developing Stigeoclonium filaments. 



A paragraph from Wolle's (I) notes upon S. fastigiatum Kg. is 

 as follows: "Some of the species of Stigeoclonium are very 

 closely related to species of Chaetophora, as is evident from 

 personal observation. Referring to Plate CHI, figs. 1, 2, two 

 thalli of Chaetophora pisiformis magnified about 250 diameters. 

 These show a few of the radial filaments, normally imbedded 

 in a firm gelatinous mucus, extending beyond the mucous 

 tegument; this figure, (1, 2,) is such a filament more fully 

 developed, drawn with all of its branches; it is one of many 

 which occurred in the same pool; Chaetophora also was pre- 

 valent in quantity. This observation may open the inquiry, 

 'is this a normal process of development? Is the plant a 

 Stigeoclonium or a Chaetophora? Or is the latter a mere con- 

 dition of development of the former?' 



"Plate CII, figs. 1-3 and 5-8. Other forms developing from 

 Chaetophora, comp. Stigeo. longipilus, and Stigeo. radians." 



In the following description, that of S. longipilus Kg., he 

 again touches upon this point. ' ' There are two distinct forms 

 of this species, the one 8-10 mm. long, represented plate CII, 

 figs. 1, 2, 3, with long bare stems and bushy tops. Kirchner 

 remarks that the species may represent a transition state, go- 

 ing over to Chaetophora. Personal observations prove the 

 reverse, Chaetophora developing Stigeoclonium." * * * 

 "Plate CII, figs. 5-9, are very much elongated filaments of 



