Asplenium ×biscayneanum

(D. C. Eaton) A. A. Eaton

Fern Bull. 12: 45. 1904.

Common names: Biscayne spleenwort
Basionym: Asplenium rhizophyllum var. biscayneanum D. C. Eaton Bull. Torrey Bot. Club 14: 97, plate 168. 1887
Treatment appears in FNA Volume 2.

Roots proliferous. Stems erect, not branched; scales blackish throughout, linear-deltate, sparse, 1–1.3 × 0.1–2.4 mm, margins entire. Leaves nearly monomorphic. Petiole green, becoming blackish in older leaves, 1–5 (–12) cm, 1/8–1/3 length of blade; indument of black, narrowly lanceolate scales. Blade dull, linear, 2-pinnate, (4–) 12–22 × 1–3.5 cm, papery, glabrous; base slightly tapered; apex narrowing gradually, not rooting. Rachis mostly blackish, green distally and in juvenile leaves, shiny, sparsely scaly. Pinnae in 9–20 pairs, oblong, 0.5–2 × 0.4–1.3 cm; apex blunt to truncate. Pinnules of 1–2 segments; segments linear-oblong, 3–6 × 1–3 mm; margins dentate; apex notched, pointed, rounded, or blunt. Veins free, evident. Sori 1–2 per segment, on both basiscopic and acroscopic sides. Spores abortive. 2n = ca. 180.


Habitat: Hammocks, on limestone rock faces
Elevation: 0–20 m

Discussion

Asplenium × biscayneanum is the hybrid of A. trichomanes-dentatum and A. verecundum, with which it occurs. This peculiar spleenwort may most readily be separated from A. trichomanes-dentatum by its deeply cut pinnae, and from A. verecundum by being only 2-pinnate and having long petioles. Chromosome pairing in A. × biscayneanum is irregular. Judging from herbarium collections, it shows considerable hybrid vigor. All the collections are from Dade County, Florida, where it may now be extirpated.

Selected References

None.

Lower Taxa

None.
... more about "Asplenium ×biscayneanum"
not rooting +
Blunt (?) +, Rounded (?) +, Pointed (?) +, Notched (?) +  and Truncate (?) +
narrowing +
Warren H. Wagner Jr. +, Robbin C. Moran +  and Charles R. Werth +
(D. C. Eaton) A. A. Eaton +
tapered +
Asplenium rhizophyllum var. biscayneanum +
simple +  and 4-pinnate +
4 cm40 mm <br />0.04 m <br /> (12 cm120 mm <br />0.12 m <br />) +
12 cm120 mm <br />0.12 m <br /> (22 cm220 mm <br />0.22 m <br />) +
1cm;3.5cm +
Biscayne spleenwort +
0–20 m +
Hammocks, on limestone rock faces +
monomorphic +
juvenile +  and older +
fertile +  and than sterile ones +
dentate +  and entire +
perforate +, reticulate +, spiny +  and winged +
not articulate +
5 cm50 mm <br />0.05 m <br /> (12 cm120 mm <br />0.12 m <br />) +
blackish +  and green +
1/8 length of blade;1/3 length of blade +
c--shaped +
1 cm10 mm <br />0.01 m <br /> (5 cm50 mm <br />0.05 m <br />) +
0.5 cm5 mm <br />0.005 m <br /> (2 cm20 mm <br />0.02 m <br />) +
0.4 cm4 mm <br />0.004 m <br /> (1.3 cm13 mm <br />0.013 m <br />) +
green +  and blackish +
proliferous +
black +  and blackish +
0.1 cm1 mm <br />0.001 m <br /> (0.13 cm1.3 mm <br />0.0013 m <br />) +
lanceolate +  and linear-deltate +
0.1mm;2.4mm +
0.3 cm3 mm <br />0.003 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
0.1 cm1 mm <br />0.001 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
acroscopic +  and basiscopic +
less lunate;linear +
dorsiventral +  and symmetric +
not branched +
Asplenium ×biscayneanum +
Asplenium +
species +
anastomosing +