| GROUP I | STERILE AND FERTILE FRONDS TOTALLY UNLIKE; |
very evidently green and neither scarce nor specially 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; pinnæ 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 pinnæ 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
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