Shape: Silvery False Spleenwort is a tall soft green color fern forming a leafy clump. It grows from a black creeping rhizome.
Fronds: Sterile and fertile fronds are the same shape although the fertile fronds are taller and a bit slimmer. They also appear later than the sterile fronds and will grow to 30 inches in height and 5 to 12 inches wide. Fertile fronds bear the sori on the underside on either side of the pinnule vein. The stipe is slightly scaly, green to straw colored and much shorter than the blade, with a shallow groove in the topside portion. This groove gives a flattened surface to the topside while the backside remains rounded. Hair remains on the stipe till mid summer.
Blades taper to the tip and are broadest at the middle. They are pinnate-pinnatifid, that is the 1st division of the pinnae is cut to the main rachis but the second division on each pinna is lobed and not cut all the way to the pinna costa. Both the rachis and the costa of the pinnae have many silvery hairs.
The Pinnae: There are 18 +/- pairs of pinnae arranged alternately on the rachis with some space between each. Each pinna can be up to 6 inches long and tapers to the tip and the base end is sessile to the rachis. The lowest pair on the blade often point downward. The groove on the top of the costa does not meet the groove on the rachis. This is typical of the Deparia.
Pinnules: The pinnules have rounded squarish tips which may have small teeth. They are not cut all the way down to the costa but form a squared off lobe at the costa.
Fertility: The sori are long and mostly straight arranged in a herringbone pattern on the underside of the pinnules. They are covered with an indusia which attaches to the vein side of the pinnule. It is silvery at first (hence the "silvery" in the common name), then turning brown. The indusia lacks a tooted edge.
Habitat: Silvery False Spleenwort requires rich, neutral to acidic moist soil in the shade. Sun is tolerated only if the soil is constantly moist. Fronds are straw-colored in the autumn.
Names: The genus Deparia is derived from the Greek depas, meaning 'saucer' and referring to the saucer shaped indusia covering the sori of the fern that is the type for this species (the indusia is more curved than saucer shape on this specific species - there are six species of this genus known in North America). The species name acrostichoides, means 'like the genus Acrostichum' (referring to the fern's resemblance to a group of Asian ferns not found in North America).
The accepted author names of the plant classification are as follows: The first to classify in 1800 using the name Asplenium acrostichoides, 'Sw.' refers to Olof Swartz, (1760-1818) Swedish botanist who was a specialist in orchids, who had a botanical collection of 6000 specimens. His work was updated in 1980 by 'M.Kato' who is Masahiro Kato, (b. 1946) Japanese botanist and Professor at the Laboratory of Systematic Botany, Graduate School of Science, University of Tokyo.
In Eloise Butler's time it was given the name Asplenium acrostichoides. It was in that genus that the "false spleenwort" portion of the common name got attached as Aspleniums are commonly known as Spleenworts - a reference to their supposed medicinal properties for spleen problems - and 'false' because it in not a true spleenwort but is more like a wood fern. The classification changed to Athyrium thelypterioides in Martha Crone's time and is now Deparia acrostichoides.
Comparisons: The Lady Fern, Athyrium filix-femina, also has pinnae that are alternate on the rachis, the lowest pinnae may point downward and the sori also form a herringbone pattern, but the pinnules of Lady Fern usually have pointed tips and the pinnule margins have small lobes where the veins reach the pinnule edge. The indusia of Lady Fern has a toothed edge and the species lacks the profuse silvery hair of the Spleenwort.
Frances Theodora Parsons wrote in 1899: "Its color is a dull green, the silvery indusia on the lower surfaces of the pinnae giving the plant its English title. Although usually its fronds are larger, their outline, tapering as it does both ways from the middle, somewhat suggests that of the New York Fern. It is readily identified, as the oblong or linear fruit-dots at once proclaim it a Spleenwort, and no other member of this tribe has fronds of the same shape.
Although it cannot be classed among the rare ferns, it is absent from many promising localities, and is associated in my mind with especially successful expeditions." From A GUIDE TO THE NAMES, HAUNTS, AND HABITS OF OUR COMMON FERNS
Silvery False Spleenwort ID notes: Above: The fronds are widest in the middle with tapering tips, upward pointing pinnae, arranged alternately. Fiddleheads are hairy.
Below: - The base pinnae usually point downward and below them the stipe has hair and a few tan scales. 3rd photo - both the rachis and costa have silvery hair. The pinna does not have a stalk. The groove of the costa does not meet the grove of the rachis. The pinnules are not cut all the way to the costa, but are left with a squared off lobe and have a blunt rounded tip.
Below: Each pinna can be up to 6 inches long and tapers to the tip and the base end is sessile to the rachis.
Below: 1st photo - The stipe has a shallow groove in the upper portion.
The sori of fertile fronds: 2nd photo - Sori are arranged in a herringbone pattern along the veins of the pinnules. A silvery color indusium covers each sorus. 3rd photo - The indusia turn a tan-brown when the sori are approaching maturity. Note the hair on both the rachis and the costa
Notes: Silvery False Spleenwort is not indigenous to the Garden area. Eloise Butler first planted it in 1909, 1911 and 1918, sourced all 3 times from Gillett's Nursery in Southwick, MA. Martha Crone planted 8 in 1933, 12 in 1937, more in '53 and 50 from Henderson's Nursery in 1956 when she was developing the Fern Glen. Most recently Curator Susan Wilkins planted 6 in 2006.
Silvery False Spleenwort's range in North America if the eastern half of the continent, excepting Florida. Minnesota and Ontario are on the western edge of the range. Within Minnesota however, it has only been found in 5 counties of the SE corner - Fillmore, Houston, Olmsted, Wabasha and Winona. The species is listed on the Minnesota "Special Concern" plant list. In Wisconsin it is widely found.
There are about 50 species of the genus Deparia in the world but only this one species is in the central and NE region of North America. It has been assigned several botanical names in the past as noted above.
References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.
Identification booklet for most of the flowering forbs and small flowering shrubs of the Eloise Butler Wildflower Garden. Details Here.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"