^ STERILE AND FERTILE FRONDS TOTALLY UNLIKE; 



kjROUP I FERTILE FRONDS NOT LEAF-LIKE IM APPEAPANCE 



very evidently green and neither scarce nor spe- 

 cially inconspicuous. 



I have found these fertile fronds apparently full- 

 grown in June, though usually they are assigned to 

 a much later date. They remain standing, brown 

 and dry, long after they have sown their spores, 

 side by side with the fresh fronds of the following 

 summer. 



Detail a in Plate I represents the so-called var. 

 obtusilobata. This is a form midway between the 

 fruiting and the non-fruiting fronds. It may be 

 looked for in situations where the fern has suffered 

 some injury or deprivation. 



2. OSTRICH FERN 



Onoclea Struthiopteris 



Nova Scotia to New Jersey, along streams and in moist woods. 

 Growing in a crown, two to ten feet high. 



Sterile fronds. — Broadly lance-shaped, once-pinnate ; f>innce 

 divided into narrowly oblong segments which do not reach the 

 midvein ; stalk short, deeply channelled in front. 



Fertile fronds. — Quite unlike the sterile fronds, growing in the 

 centre of the crown formed by the sterile fronds, shorter, erect, 

 rigid, with green, necklace-like pinnae which hold the spore-cases ; 

 appearing in July. 



I first found this plant at its best on the shore of 

 the Hoosick River in Rensselaer County, N. Y. 

 We had crossed a field dotted with fragrant heaps 

 of hay and blazing in the midsummer sun, and had 

 entered the cool shade of the trees which border the 

 river, when suddenly I saw before me a group of 

 ferns of tropical beauty and luxuriance. Great 



56 



