Part 17

Fertile fronds.--Quite unlike the sterile fronds and shorter, erect, rigid, contracted; pinnules rolled up into dark-green, berry-like bodies which hold the spore-cases; appearing in June or July.

This is one of our commonest ferns, growing in masses along the roadside and in wet meadows. Perfectly formed sterile fronds are found of the tiniest dimensions. Again the plant holds its own among the largest and most effective ferns. From its creeping rootstock rise the scattered fronds which at times wear very light and delicate shades of green. There is nothing, however, specially fragile in the plant's appearance, and one is struck by the inappropriateness of its title. It is probable that this arose from its sensitiveness to early frosts.

Though one hesitates to differ from Dr. Eaton, who described the fertile fronds as "nearly black in color" and said that they were "not very common," and that a young botanist might "search in vain for them for a long time," my own experience has been that the fresh ones are 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 plume-like fronds of a rich green arched above my head. From the midst of the circle which they formed sprang the shorter, dark, rigid fruit-clusters. I was fairly startled by the unexpected beauty and regal bearing of the Ostrich Fern.

SENSITIVE FERN

a. Var. obtusilobata]

This magnificent plant luxuriates especially in the low, rich soil which is subject to an annual overflow from our northern rivers. Its vase-like masses of foliage somewhat suggest the Cinnamon Fern, but the fertile fronds of the Ostrich Fern mature in July, some weeks later than those of its rival. They are dark-green, while those of the Cinnamon Fern are golden-brown. Should there be no fruiting fronds upon the plant, the Ostrich Fern can be distinguished by the free veins with simple veinlets (Plate II, a) of its pinnæ, the veins of the Cinnamon Fern being free and its veinlets forking (Pl. III, a), and by the absence of the tuft of rusty wool at the base of the pinnæ on the under side of the frond.

The Ostrich Fern does so well under cultivation that there is danger lest it crowd out its less aggressive neighbors. It propagates chiefly by means of underground runners. Mr. Robinson describes a specimen which he had planted in his out-door fernery that crawled under a tight board fence and reappeared in the garden of his neighbor, who was greatly astonished and equally delighted so unexpectedly to become the owner of the superb plant.

OSTRICH FERN

a Portion of sterile frond b Fertile frond c Detail, showing free veins with simple veinlets]

The Ostrich Fern, like its kinsman the Sensitive Fern, occasionally gives birth to fronds which are midway between its fruiting and its non-fruiting forms. This is specially liable to occur when some injury has befallen the plant.

3. CINNAMON FERN

Osmunda cinnamomea

Nova Scotia to Florida, in swampy places. Growing in a crown, one to five feet high.

Sterile fronds.--Broadly lance-shaped, once-pinnate; pinnæ cut into broadly oblong divisions that do not reach the midvein, each pinna with a tuft of rusty wool at its base beneath.

Fertile fronds.--Quite unlike the sterile fronds, growing in the centre of the crown formed by the sterile fronds and usually about the same height; erect, with cinnamon-colored spore-cases.

In the form of little croziers, protected from the cold by wrappings of rusty wool, the fertile fronds of the Cinnamon Fern appear everywhere in our swamps and wet woods during the month of May. These fertile fronds, first dark-green, later cinnamon-brown, are quickly followed and encircled by the sterile ones, which grow in a tall, graceful crown. The fertile fronds soon wither, and, during the summer, may be found either clinging to the stalks of the sterile fronds or lying on the ground.

CINNAMON FERN

a Showing tuft of wool at base of pinna, also free veins with forking veinlets]

The Cinnamon Fern is often confused with the Ostrich Fern. When either plant is in fruit there is no excuse for this mistake, as the cinnamon-colored spore-cases of the former appear in May, while the dark-green fertile fronds of the latter do not ripen till July. When the fruiting fronds are absent the forked veinlets (Plate III, a) of the Cinnamon Fern contrast with the simple veinlets of the other plant (Plate II, a). Then, too, the pinnæ of the Cinnamon Fern bear tufts of rusty wool at the base beneath, the remnants of the woolly garments worn by the young fronds.

The plant is a superb one when seen at its best. Its tall sterile fronds curve gracefully outward, while the slender fruit-clusters erect themselves in the centre of the rich crown. In unfavorable conditions, when growing in dry meadows, for instance, like all the Osmundas, and indeed like most growing things, it is quite a different plant. Its green fronds become stiff and stunted, losing all their graceful curves, and its fruit-clusters huddle among them as if anxious to keep out of sight.