[Footnote 1: Recently donated to the Gray Herbarium.]
For numerous facts and suggestions we are indebted to the twenty volumes of the Fern Bulletin, and also to its able editor, Mr. Willard N. Clute. To him we are greatly obligated for the use of photographs and plates, and especially for helpful counsel on many items. We appreciate the helpfulness of the American Fern Journal and its obliging editor, Mr. E.J. Winslow. To our friend, Mr. C.H. Knowlton, our thanks are due for the revision of the checklist and for much helpful advice, and we are grateful to Mr. S.N.F. Sanford, of the Boston Society of Natural History, for numerous courtesies; but more especially to Mr. C.A. Weatherby for his expert and helpful inspection of the entire manuscript.
The illustrations have been carefully selected; many of them from original negatives bequeathed to the author by his friend, Henry Lincoln Clapp, pioneer and chief promoter of school gardens in America. Some have been photographed from the author's herbarium, and from living ferns. A few are from the choice herbarium of Mr. George E. Davenport, and also a few reprints have been made from fern books, for which due credit is given. The Scott's spleenwort, on the dedication page, is reprinted from Clute's "Our Ferns in Their Haunts."
[INTRODUCTION]
Thoreau tells us, "Nature made a fern for pure leaves." Fern leaves are in the highest order of cryptogams. Like those of flowering plants they are reinforced by woody fibres running through their stems, keeping them erect while permitting graceful curves. Their exquisite symmetry of form, their frequent finely cut borders, and their rich shades of green combine to make them objects of rare beauty; while their unique vernation and method of fruiting along with their wonderful mystery of reproduction invest them with marked scientific interest affording stimulus and culture to the thoughtful mind. By peculiar enchantments these charming plants allure the ardent Nature-lover to observe their haunts and habits.
"Oh, then most gracefully they wave
In the forest, like a sea,
And dear as they are beautiful
Are these fern leaves to me."
As a rule the larger and coarser ferns grow in moist, shady situations, as swamps, ravines, and damp woods; while the smaller ones are more apt to be found along mountain ranges in some dry and even exposed locality. A tiny crevice in some high cliff is not infrequently chosen by these fascinating little plants, which protect themselves from drought by assuming a mantle of light wool, or of hair and chaff, with, perhaps, a covering of white powder as in some cloak ferns--thus keeping a layer of moist air next to the surface of the leaf, and checking transpiration.
Some of the rock-loving ferns in dry places are known as "resurrection" ferns, reviving after their leaves have turned sere and brown. A touch of rain, and lo! they are green and flourishing.
Ferns vary in height from the diminutive filmy fern of less than an inch to the vast tree ferns of the tropics, reaching a height of sixty feet or more.