PINNA. One of the primary divisions of a frond.

PINNATE. Feather-like; with the divisions of the frond extending fully to the rachis.

PINNaTIFID. Having the divisions of the frond extend halfway or more to the rachis or mid vein.

PINNULE. A secondary pinna. In a bipinnate frond one of the smaller divisions extending to the secondary midvein.

PROc.u.mBENT. Lying on the ground.

PROTHaLLIUM. (Or prothallus.) A delicate, cellular, leaf-like structure produced from a fern spore, and bearing the s.e.xual organs.

PTERIDoPHYTA. A group of flowerless plants embracing ferns, horsetails, club mosses, etc.

p.u.b.eSCENT. Covered with fine, soft hairs; downy.

RaCHIS. The continuation of the stipe through the blade or leafy portion of the fern.

REFLEXED. Bent abruptly downward or backward.

RENIFORM. Kidney-shaped.

REVOLUTE. Rolled backward from the margin or apex.

ROOTSTOCK. (Or rhizome.) An underground stem, from which the fronds are produced.

SCAPE. A naked stem rising from the ground.

SEGMENT. One of the smaller divisions of a pinnatifid frond.

SERRATE. Having the margin sharply cut into teeth pointing forward.

SeRRULATE. The same only with smaller teeth.

SESSILE. Without a stalk.

SINUS. A cleft or rounded curve between two lobes.

SiNUATE. With strongly wavy margins.

SORUS A cl.u.s.ter of sporangia; a fruit dot.

(plu. SORI).

SPaTULATE. Shaped like a druggist's spatula or a flattened spoon.

SPIKE. An elongated cl.u.s.ter of sessile sporangia.

SPiNULOSE. Spiny; set with small, sharp spines.

SPORANGE (plu. A spore case. A tiny globe in which SPORANGIA). the spores are produced.

STIPE. The stem of a fern from the ground up to the leafy portion; the leaf stalk.

STOLON. An underground branch or runner.

SuBULATE. Awl-shaped.

TeRNATE. With three nearly equal divisions.

TRUNCATE. Ending abruptly as if cut off.

TUFT. Things flexible, closely grouped into a bunch or cl.u.s.ter.

VENATION. The veining of a frond or leaf.

VERNATION. The arrangement of leaves in the bud.

WHORL. A circle of leaves around a stem.

WINGED. Margined by a thin expansion of the rachis.

NOTE

The student should have some idea of the terms _genus_, _species_ and _variety_, although they are not capable of exact definition.

A _species_, or kind, is in botany the unit of cla.s.sification. It embraces all such individuals as may have originated in a common stock. Such individuals bear an essential resemblance to each other, as well as to their common parent in all their parts. E.g., the Cinnamon fern is a kind or species of fern with the fronds evidently of one kind, and of a common origin, and all producing individuals of their own kind by their spores or rootstocks. When such individuals differ perceptibly from the type in the shape of the pinnae, or the cutting of the fronds, we have _varieties_ as _frondsum_, _incsum_, etc. Or if the difference is less striking the word _form_ is used instead of variety, but in any given case opinions may differ in respect to the more fitting term.

A _genus_ is an a.s.semblage of species closely related to each other, and having more points of resemblance than of difference; e.g., the royal fern, the cinnamon fern, and the interrupted fern are alike in having similar spore cases borne in a somewhat similar manner on the fronds, and forming the genus _Osmunda_. In like manner certain members of the clover group--red, white, yellow, etc., make up the genus _Trifolium_.

Thus individuals are grouped into species and species are a.s.sociated into genera, and the two groups are united to give each fern or plant its true name, the generic name being qualified by that of the species; as in the cinnamon fern _Osmunda_ (genus), _cinnammea_ (species).

CHECK LIST OF THE FERNS OF NORTHEASTERN AMERICA

In the following list the first name is usually the one adopted in the text, and those that follow are synonyms.

Names printed in small capitals are those of the newer nomenclature, now adopted at the Gray Herbarium but not in the Manual.

ADIANTUM L.

1. Adiantum Capillus-Veneris L.

2. Adiantum pedatum L.

Var. ALEUTIc.u.m RUPR.

ASPIDIUM SW.

3. Aspidium Boottii. Tuckerm.

Dryopteris Boottii. (Tuckerm.) Underw.

THELYPTERIS BOOTTII. (Tuckerm.) Nieuwl.

4. Aspidium cristatum. (L.) Sw.

Dryopteris cristata. (L.) A. Gray.

THELYPTERIS CRISTATA. (L.) Nieuwl.

5. Aspidium cristatum var. Clintonianum. D.C. Eaton.

Dryopteris cristata var. Clintoniana. (D.C. Eaton.) Underw.

THELYPTERIS CRISTATA var. CLINTONIANA. (D.C. Eaton.) Weatherby.

6. Aspidium cristatum marginale. Davenp.

7. Aspidium Filix-mas. (L.) Sw.

Dryopteris Filix-mas. (L.) Sw.

THELYPTERIS FILIX-MAS. (L.) Nieuwl.

8. Aspidium fragrans. (L.) Sw.

Dryopteris fragrans. (L.) Schott.

THELYPTERIS FRAGRANS. (L.) Nieuwl.

9. Aspidium Goldianum. Hook.

Dryopteris Goldiana. (Hook.) A. Gray.

THELYPTERIS GOLDIANA. (Hook.) Nieuwl.

10. Aspidium marginale. (L.) Sw.

Dryopteris marginalis. (L.) A. Gray.

THELYPTERIS MARGINALIS. (L.) Nieuwl.

11. Aspidium noveboracense. (L.) Sw.

Dryopteris noveboracensis. (L.) A. Gray.

THELYPTERIS NOVEBORACENSIS. (L.) Nieuwl.

12. Aspidium simulatum. Davenp.

Dryopteris simulata. Davenp.

THELYPTERIS SIMULATA. (Davenp.) Nieuwl.

13. Aspidium spinulosum. (O.F. Muell.) Sw.

Dryopteris spinulosa. (O.F. Muell.) Kuntze.

THELYPTERIS SPINULOSA. (O.F. Muell.) Nieuwl.

14. Aspidium spinulosum var. intermedium. (Muhl.) D.C. Eaton.

Dryopteris spinulosa var. intermedia. (Muhl.) Underw.

THELYPTERIS SPINULOSA var. INTERMEDIA. (Muhl.) Nieuwl.