Flora of North America species comparison

The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

Cystopteris laurentiana

cystoptère laurentienne, Laurentian bladder fern, Laurentian fragile fern, St. Lawrence bladderfern
Stems

creeping, not cordlike, internodes very short, less than 5 mm, heavily beset with old petiole bases, hairs absent;

scales uniformly brown to ± clathrate, radial walls brown, luminae clear.
Leaves

monomorphic, clustered at stem apex, to 45 cm, nearly all bearing sori.
Petiole

usually dark at base, grading to straw-colored distally, shorter than blade, sparsely scaly at base.
Blade

ovate to narrowly ovate, 2-pinnate to 2-pinnate-pinnatifid, widest above base, apex short-attenuate;

rachis and costae usually sparsely invested with unicellular, gland-tipped hairs, occasionally with misshapen bulblets;

axils of pinnae with occasional multicellular, gland-tipped hairs.
Pinnae

typically perpendicular to rachis, not curving toward blade apex, margins serrate;

proximal pinnae pinnate-pinnatifid to pinnatifid, ± equilateral, basiscopic pinnules not enlarged, basal basiscopic pinnules sessile to short-stalked, base truncate to obtuse;

distal pinnae ovate to oblong.
Veins

directed into teeth and notches.
Indusia

cup-shaped, apex truncate, typically sparsely invested with unicellular, gland-tipped hairs.
Spores

spiny, usually 49–60 µm. 2n = 252.

Cystopteris laurentiana
Phenology Sporulating summer–fall.
Habitat Cracks and ledges on cliffs, often on calcareous substrates
Elevation 0–1000 m (0–3300 ft)
Distribution
from FNA
CT; IA; IL; MA; MI; MN; PA; VT; WI; NB; NF; NS; ON; QC
[WildflowerSearch map]
[BONAP county map]
Discussion

Cystopteris laurentiana is a sexual allohexaploid species with C. bulbifera as the diploid parent and C. fragilis as the tetraploid. Cystopteris laurentiana was previously thought to be common only in the Great Lakes region (R. F. Blasdell 1963); it is now known to occur frequently in the Driftless Area of the Midwest. Because C. laurentiana can be difficult to distinguish from C. fragilis, specimens with ovate leaves having unusually large spores and growing on moist cliffs should be checked carefully for occasional glandular hairs, the distinguishing feature of C. laurentiana. Sterile pentaploid hybrids between C. laurentiana and C. fragilis have been discovered where the two species are sympatric.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 2.
Parent taxa Dryopteridaceae > Cystopteris
Sibling taxa
C. bulbifera, C. fragilis, C. montana, C. protrusa, C. reevesiana, C. tennesseensis, C. tenuis, C. utahensis
Synonyms C. fragilis var. laurentiana
Name authority (Weatherby) Blasdell: Mem. Torrey Bot. Club 21(4): 51. (1963)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



Type/paste one or more Latin names into the boxes above; matching taxa will show up below the box as you type. You can use the up/down arrow keys to move through the list.

(If the plant you're looking for doesn't show up in the auto-complete list, that means it either isn't described in Flora of North America yet, or it's listed under a synonym. And please note that Flora of North America is still missing several plant families, including Fabaceae, Apiaceae, Boraginaceae, and Polemoniaceae.)

Choose a data source: Flora of North America

The species comparison tool is brought to you by:
Northwest Wildflowers