Acute. Ending in a sharp point.

Appressed. Tending to be parallel to margin—not divergent.

Auricled. Having a somewhat ear-shaped lobe.

Bipinnate. Twice pinnate—applied to a frond completely divided into pinnae and the pinnae divided into pinnules.

Blade. The leafy portion of a frond.

Calcareous. Containing lime (applied to rock).

Chaffy. With dry scales.

Confluent. Running into each other.

Cordate. Heart-shaped (two rounded lobes with a notch between).

Crenate. Shallowly cut into rounded teeth.

Crenulate. Finely or slightly crenate, with very small rounded teeth.

Crown. Close cluster of fronds produced from an end-bud on a rootstock.

Deciduous. Withering away in autumn or at end of growing season.

Deltoid. Shaped like an equilateral triangle or like an isosceles triangle with base somewhat shorter than sides.

Elliptic. Shaped somewhat like an ellipse—widest in the middle.

Entire. Descriptive of a margin which is not toothed or lobed, or of a blade which is not lobed or deeply cut.

Fertile. Bearing spores.

Frond. A fern leaf, consisting of blade and stipe.

Fruit-dot. Another name for sorus (a cluster of sporangia).

Glabrous. Smooth, without hairs or scales.

Gland. A secreting structure, usually a globule at the tip of a hair.

Glandular. Bearing glands.

Incised. Sharply and deeply cut.

Indusium (plural indusia). A thin tissue covering a sorus or fruit dot.

Linear. Long and narrow.

Lobes. Divisions of a frond, pinna, or pinnule, when division is not complete—usually applied to small rounded divisions. (See segment and ultimate divisions.)

Medial. Descriptive of sori, midway between midvein and margin.

Non-calcareous. Not containing lime (applied to rock).

Oblong. Longer than wide, with the long sides parallel.

Obtuse. Blunt or rounded at tip.

Ovate. Egg-shaped in outline.

Panicle. A compound, loose group of sporangia.

Pinnae (singular pinna). The primary divisions of a frond where division extends completely to the rachis.

Pinnate. Divided into pinnae.

Pinnatifid. Applied to a frond divided into lobes or segments, but not completely into pinnae, or to pinnae not completely divided into pinnules.

Pinnules. Divisions of the pinnae where division is complete (term lobe or segment is used where division is not complete).

Pubescent. Hairy.

Rachis. The axis extending from the top of the stipe through the blade of a pinnate frond.

Reflexed. Bent abruptly downward or backward.

Revolute. Turned under at a margin.

Rootstock or rhizome. Horizontal or short erect underground stem, producing buds which develop into new fronds.

Segment. Division of a frond, pinna, or pinnule, when division is not complete. (See lobes.)

Serrate. Saw-toothed, with sharp teeth pointing forward.

Sessile. Attached without a stalk.

Sorus (plural sori). A cluster of sporangia, with or without an indusium.

Spike. An elongated axis on which sporangia are closely set.

Spinulose. Bearing small points. Margins which are spinulose-serrate or spinulose-toothed bear one of these small points at the end of each tooth.

Sporangia (singular sporangium). Spore cases, structures containing the spores.

Spore. Reproductive cell of ferns.

Stalk. General term for any supporting organ—may be used for stipe of frond or attachment of pinna, similar to petiole of a leaf.

Sterile frond. A frond which does not produce spores.

Stipe. The stalk below the blade of a frond.

Talus. Loose rock at the base of a cliff.

Ternate. Separated into three more or less equal divisions.