Osmunda Osmundaceae 41 



Supplementary Key for the Separation of Sterile Fronds of Some 

 Species That Superficially Look Much Alike. 



In my early study of ferns I was not aware that sterile fronds could be 

 identified. Sterile specimens of Osmunda and Pteretis much resemble each 

 other and I had never been able to find the last named genus until I was 

 able to identify the sterile specimen. Since that time I have found several 

 colonies and I think if all of our fern students knew how to separate these 

 genera that many more colonies of Pteretis would be found. Likewise 

 there is a possibility that sterile specimens of Woodiva?'dia virginica and 

 certain species of Athyrium and Dryoyteris might be confused with Os- 

 munda. Hence this key. 



Veins simple, not forked; pinnules entire; vascular bundles in stipe 7 Pteretis. 



Veins not simple, more or less forked. 



Veins usually forked once ; vascular bundle in the stipe 1 ; stipe stramineous. 



Sterile fronds with tufts of wool at the base of the pinnae . . Osmunda cinnamomea. 



Sterile fronds without tufts of wool at the base of the pinnae 



Osmunda Claytoniana. 



Veins with areolae on both sides of the midrib with which simple or rarely forked 



veins connect the margin; vascular bundles more than 5; stipe dark brown. 



Woodwardia. 



1. Osmunda regalis L. var. spectabilis (Willd.) Gray. (Rhodora 21: 

 179. 1919.) (Osmunda regalis of Gray, Man., ed. 7 and Britton and Brown, 

 Illus. Flora, ed. 2, not L.) Royal Fern. Map 6. Frequent in the lake area 

 and infrequent to local south of it. It is not especially particular as to its 

 habitat except that it must be a moist or wet one. It is found mostly in 

 low woods, about ponds and lakes, and less frequently in the open in wet 

 prairies. 



Newf. to Sask., southw. to Fla. and Miss. 



2. Osmunda Claytoniana L. Interrupted Fern. Map 7. Infrequent 

 to local throughout the greater part of the state. Besides the counties 

 shown on the map, there are reports from thirteen additional counties. It 

 seems to prefer the moist bases of black and white oak slopes. In the 

 southern part of the state it is found on the slopes of deep, wooded ravines. 



Newf. to Minn., southw. to N. C., Ky., and Mo. ; a variety also in s. Asia. 



3. Osmunda cinnamomea L. CINNAMON FERN. Map 8. Frequent in the 

 lake area, becoming infrequent to local south of it. In the lake area it is 

 usually common in tamarack bogs and swamps about lakes, and in the 

 southern part of the state it grows in low, fiat woods, associated with sweet 

 gum and red maple. Throughout its range it is found only in wet soil in 

 bogs or about ponds and marshes and rarely on shaded slopes. 



Newf. to Minn., southw. to Fla., La., and N. Mex. ; also in Mex., S. A., 

 W. I., and Eurasia. 



3a. Osmunda cinnamomea f. auriculata (Hopkins) Kittredge. (Bull. 

 Conn. State Geol. and Nat. Hist. Surv. 48: 12. 1931.) This form has the 

 basal segments much elongated and deeply and sharply toothed on the 

 lower side or rarely on both sides. The other segments are normal or 

 nearly so. It has been found in Porter County by R. M. Tryon, Jr. 



