Lucien Marcus Underwood

“ When we add to these peculiar forms of our own country those of foreign lands, and include the immense tree-ferns of tropical regions, we find our early conception of a fern inadequate to cover this diversity of forms. ”

“ Ceratopteris is an anomalous genus from southern Florida, having a few sori arranged on two or three veins parallel to the midvein, and covered by the broadly reflexed margin of the frond. It properly forms the type of a family.
41. Struthiopteris (Fig. 7) is intermediate between those genera in which there is an indusium formed of the revolute margin of the frond and those in which the indusium is remote from the margin. Our single species has dimorphous fronds, free veins, and the fructification in a broad band next the midvein, covered by acontinuous and distinctly intramarginal indusium. ”

“ Mode of Growth.—Ferns vary greatly in their method of growth, yet each species has a plan which, within certain limits, is fixed and definite. Some, like the common brake, have their fronds rising from more or less distant portions of the creeping rootstock. Others, like Asplenium trichomanes, are tufted, many fronds rising irregularly in a cluster; while still others, like the ostrich-fern (Matteuccia) , and many shieldferns (Dryopteris) , grow in crowns or circles, the later fronds continually rising within the older ones. ”

“ The Ferns, on the contrary, produce no flowers. Instead of seeds developed from fertilized ovules, minute spores are produced asexually, from which new ferns are developed by a peculiar process of germination very unlike that of flowering plants. These spores are collected in little sacs known as sporangia or spore cases. The sporangia in the true ferns (Polypodiaceæ) are collected in little clusters on the back of the frond, or are variously arranged in lines along the veins or around the margins (Fig. 1) . ”

“ The numerous species of spleenworts are closely related to each other in their methods of fructification, but differ widely in the form, texture, and cutting of their fronds. The sori are placed on the upper side of an oblique vein (sometimes crossing it in § Atheyrium) , and covered by an indusium of the same shape attached by its edge to the fruiting vein and opening toward the midvein. In some species part of the indusia are double. The veins are free in all our species. In § Euasplenium the sori are straight or slightly curved ”

“ To understand thoroughly an animal we must study its habits in its native haunts. To know its structure and position in the animal kingdom we must carefully dissect a large number of specimens, and study the development of the individual from its beginning. ”

“ Some are stout and fleshy, others are delicate and even filmy, but most are herbaceous, resembling ordinary flowering plants in the texture of their foliage. While most would be recognized as ferns by even a novice, a few differ so widely from the ordinary typical forms that to an unskilled observer they would scarcely be considered as bearing any resemblance to ferns whatever. The fronds of one of our Florida species resemble narrow blades of grass, and the fertile spikes of another from New Jersey might be mistaken for a diminutive species of sedge. ”

“ It will be readily seen that this is merely a modified form of the ordinary pinnate frond. Throughout the domain of nature there is infinite variety of form and structure, and at the same time unity in plan and conformity to a few generalized types.
25. Venation.— The method of veining admits of great variation, often serving to distinguish species, and more especially the sections of the various genera. In some ferns, like most shield-ferns (Dryopteris) , the veins are free — that is, arising from either side of the midvein they do not unite with any other vein. ”

“ Of necessity, such species are of comparatively small size, and likely to be protected in some way against the heat of the sun, and provided with means to retain their moisture in times of drought. Others still are found in wet, rocky ravines, often where moistened by the spray of cascades or waterfalls, and consequently have no such provision against the heat of an extended summer. Certain others thrive in open fields that are comparatively dry and unshaded. One species of Southern Florida is aquatic, having the sterile fronds floating in shallow water. ”

“ The exquisite delicacy and the extent to which this dividing is carried in some ferns determines largely their æsthetic value.
The continuation of the stipe through a simple frond is called the midvein; through a compound frond is called the rachis, and is further distinguished as primary when the frond is much compounded. A frond is entire when the margin forms an unbroken line; when so cut as to form lobes extending half way or more to the midvein it is called pinnatifid ”

“ To form a correct understanding of ferns we must study the ferns themselves as well as the text-book, as it is only by direct contact with nature that we gain definite and satisfactory information. The text-book is useful only in giving directions how to investigate. ”

“ Ferns are largely dependent for successful growth on the amount of warmth, moisture, and shade to which they are subjected, and we would naturally expect to find them reaching a maximum in size and abundance in warm swamps or shady marshes. While this is in general true, we nevertheless find many species thriving only in rocky places, thrusting their roots into the crevices of the rocks with little earth for their nourishment, and many times exposed to the scorching rays of the sun. ”

“ In the entire vegetable world there are probably no forms of growth that attract more general notice than the Ferns. Delicate in foliage, they are sought for cultivation in conservatories and Wardian cases, and when dried and pressed add to the culture of many a domestic circle by serving as household decorations. ”

“ Some of the species of Botrychium show the same tendency, especially in their fertile segments. It is probable that all our species will be found to fork under certain conditions. More definite information is desirable with regard to many species that show this tendency, as it doubtless involves the question of ancestry of existing ferns.
7. In those species whose sterile and fertile fronds are unlike, forms often appear that are intermediate between the sterile and fertile fronds, and sometimes even form a graded series from one to the other. ”

“ Many other ferns are found occasionally in openings of the forest or recent clearings, where they maintain a sickly existence, sometimes for a series of years. In such locations ferns often become contracted and abnormal in growth, and take on a faded yellow hue from their exposure to the open sunshine. ”

“ The various methods of fructification can be best understood by describing the peculiarities of the various genera in regular succession and noting the variations occurring in the sections or sub-genera. ”

“ Blechnum. — In this genus the sori are linear and near the midvein, and are covered by a membranous indusium which is fixed at its outer margin, bursting at its inner margin when the sporangia are mature. A single representalive is found within our limits.
43. Woodwardia. — Three Species of chain-ferns occur within our limits, and each represents a distinct section based on the methods of venation. ”

“ In like manner the marginal shield-fern (Dryopteris marginalts) , usually two or three feet high, is reduced to five inches when growing on rocky cliffs, and yet regularly produces fruit.*
* Cf. Bulletin Torrey Botanical Club, VI. 266 (Oct. 1878) . ”