TROT IP VI F R TILE AND STERILE FRONDS LEAF-LIKE 

 AND USUALLY SIMILAR ; FRUIT-DOTS ROUND 



delight in this new promise we forget for a mo- 

 ment to mourn the vanishing summer. 



The outline of the Common Bladder Fern sug- 

 gests that of the Obtuse Woodsia. The two plants 

 might be difficult to distinguish were it not for the 

 difference in their indusia. At maturity the indu- 

 sium of the Common Bladder Fern usually disap- 

 pears, leaving the fruit-dot naked, while that of the 

 Obtuse Woodsia is fastened underneath the fruit- 

 dot and splits apart into jagged, spreading lobes. 



The sterile fronds of the Slender Cliff Brake also 

 have been thought to resemble this fern, in whose 

 company it often grows. 



Williamson says that the Common Bladder Fern 

 is easily cultivated either in mounds or on rock- 

 work. 



54. RUSTY WOODSIA 



Woodsia Ilvensis 



From Labrador and Greenland south to North Carolina and Ken- 

 tucky, usually on exposed rocks in somewhat mountainous regions. 

 A few inches to nearly one foot high. 



Fronds. Oblong-lance-shaped, rather smooth above, the stalk 

 and under surface of the frond thickly clothed with rusty chaff, 

 once-pinnate ; pinna oblong, obtuse, sessile, cut into oblong seg- 

 ments ; fruit-dots round, near the margin, often confluent at matur- 

 ity ; indusium detached by its base under the sporangia, dividing 

 into slender hairs which curl above them. 



Last Decoration Day, while clambering over 

 some rocky cliffs in the Berkshire Hills, I found the 

 Rusty Woodsia growing in masses so luxuriant to 

 the eye and so velvety to the touch that it hardly 



200 



