Al Schneider's Rocky Mountains Plant Descriptions

American Rockbrake
Cryptogramma acrostichoides
Brake family (Pteridaceae)

Look for these lacy ferns as you walk through and talus slopes and rocky hillsides at higher elevations. Notice the two distinct types of : the lower, rounded- are sterile; the taller are fertile. This species is circumboreal. In 1753 Linnaeus named this species Osmunda crispa from specimens collected in England and Sweden. Robert Brown renamed this and species in 1823 from specimens collected by Richardson on the Canadian Franklin Expedition. "Cryptos" is Greek for "hidden" and "gramma" for "line," and taken together the two refer to the lines of hidden by the rolled leaf margins. "Acrostichoides" means "similar to plants of the Acrostichum." (The Greek "oides" means "similar to.")


©2014 Susan McDougall, Trees Live Here.

Description

Rootstocks short, often in massive tufts, tufted, numerous, of two types on same plant: fertile and infertile. Fertile ones are 2-12" long, surpassing the sterile in size; are straw-colored, sterile 1-5" long, 2-3 times , . Fertile simpler with fewer segments, these , 1/4 to 1/2" long, margins covering .

Field Marks

Shorter sterile and longer fertile on same plant; tucked into rock crevices.

© Al Schneider

lobe -- Being divided by clefts.

frond -- a large, divided leaf. The leaves of most ferns are fronds.

ovate -- Oval, egg-shaped, with a tapering point.

A stipe is a small stalk that supports some other structure. In ferns, the stalk of a frond; generally a small stalk.

sori -- The dots on the back of fern fronds. These sori are groupings of many sporangia, each of which encloses numbeous spores, the reproductive bodies of ferns.

revolute -- With margins rolled backward and under onto the lower side of a leaf.

scree -- field of small, loose, slab rock. Common high on mountains.

pinnate -- A compound leaf with two rows of leaflets.

sporangium is the enclosure in which spores are formed.

genus -- A subdivision of a botanical Family in which all members have a significant number of similar characteristics.

blade -- Just the flat part of a leaf. Not the stem.

glabrous -- smooth, glossy, having no bristles or hair-like structures. Bald.

linear -- Long and very narrow like a blade of grass.