Pseudopedate
Encyclopedia
Pseudopedate is a term used in botany
to describe the leaf architecture of certain ferns in the genus Adiantum (maidenhair ferns).
, have been described as having a pedate
leaf architecture, with a forked rachis
which bears subdivided pinna
e along the outer edge of its two outward- and backward-curving branches. However, a forking (dichotomizing) rachis is not characteristic of any other members of the Polypodiaceae
. A more accurate description of such leaves was put forth by Margaret Slosson in 1906, and improved upon by Herb Wagner in the 1950s.
Slosson and Wagner showed that, in fact, the central one of the apparent "pinnae" contains the rachis of the blade; the "pinnules" adorning it are the medial and ultimate pinnae. The two basal pinnae not only form the "pinnae" flanking the first "pinna" (containing the rachis), but their basal basiscopic pinnules are enlarged into another set of apparent "pinnae". (The basal acroscopic pinnules are comparable In a sufficiently large specimen, the basal basiscopic segments of these are also so enlarged into another set, and so forth.
Within the genus, this architecture is shared by A. aleuticum
, A. patens, A. pedatum, A. viridimontanum
, and sometimes A. hispidulum
.
Botany
Botany, plant science, or plant biology is a branch of biology that involves the scientific study of plant life. Traditionally, botany also included the study of fungi, algae and viruses...
to describe the leaf architecture of certain ferns in the genus Adiantum (maidenhair ferns).
Plants
Historically, certain of the maidenhair ferns, such as Adiantum pedatumAdiantum pedatum
Adiantum pedatum is a maidenhair fern native to moist woodland in eastern North America.Adiantum aleuticum was once considered a subspecies...
, have been described as having a pedate
Pedate
Pedate is a term used in biology to describe certain structures resembling feet, or the quality of having feet. It derives from the Latin verb "pedo", meaning "to furnish with feet".-Plants:...
leaf architecture, with a forked rachis
Rachis
Rachis is a biological term for a main axis or "shaft".-In zoology:In vertebrates a rachis can refer to the series of articulated vertebrae, which encase the spinal cord. In this case the rachis usually form the supporting axis of the body and is then called the spine or vertebral column...
which bears subdivided pinna
Pinna
In animal anatomy, the pinna is the visible part of the ear that resides outside of the head ....
e along the outer edge of its two outward- and backward-curving branches. However, a forking (dichotomizing) rachis is not characteristic of any other members of the Polypodiaceae
Polypodiaceae
Polypodiaceae is a family of polypod ferns, which includes more than 60 genera divided into several tribes and containing around 1,000 species. Nearly all are epiphytes, but some are terrestrial.-Description:...
. A more accurate description of such leaves was put forth by Margaret Slosson in 1906, and improved upon by Herb Wagner in the 1950s.
Slosson and Wagner showed that, in fact, the central one of the apparent "pinnae" contains the rachis of the blade; the "pinnules" adorning it are the medial and ultimate pinnae. The two basal pinnae not only form the "pinnae" flanking the first "pinna" (containing the rachis), but their basal basiscopic pinnules are enlarged into another set of apparent "pinnae". (The basal acroscopic pinnules are comparable In a sufficiently large specimen, the basal basiscopic segments of these are also so enlarged into another set, and so forth.
Within the genus, this architecture is shared by A. aleuticum
Adiantum aleuticum
Adiantum aleuticum is a species of fern in the genus Adiantum, native mainly to western North America from the Aleutian Islands of Alaska, south to Chihuahua, and also locally in northeastern North America from Newfoundland south to Maryland.The fronds grow to 15-110 cm high, and are...
, A. patens, A. pedatum, A. viridimontanum
Adiantum viridimontanum
Green Mountain maidenhair fern is a rare fern limited to outcrops of serpentine rock in New England and Canada. A hybrid between Adiantum pedatum and Adiantum aleuticum , it closely resembles its parent species...
, and sometimes A. hispidulum
Adiantum hispidulum
Adiantum hispidulum, commonly known as Rough Maidenhair Fern or five-fingered jack, is a small fern in the family Adiantaceae of widespread distribution. It is found in Africa, Australia, Polynesia, Malesia, New Zealand and other Pacific Islands...
.