Asplenium plenum

E. P. St. John ex Small

Ferns S. E. States 173. 1938.

Common names: Ruffled spleenwort
Treatment appears in FNA Volume 2.

Roots proliferous. Stems erect, unbranched; scales blackish throughout, narrowly deltate, 0.4–1.1 × 0.3–0.7 mm, margins entire to denticulate. Leaves monomorphic. Petiole blackish throughout, dull, 2–6 (–10) cm, 1/4–2/5 length of blade; indument absent. Blade lanceolate, 1–2-pinnate, (4–) 8–12 (–15) × 1.5–5 cm, thin, glabrous; base not tapered; apex gradually narrowing. Rachis mostly green except occasionally blackish at base, dull, glabrous. Pinnae in (5–) 10–20 (–25) pairs, oblong-deltate, 1–3.5 × 0.5–1.8 cm; base excavate on basiscopic side; apex pointed. Pinnules linear to oblong, 4–10 mm; apex mostly notched. Veins free, not conspicuous. Sori mostly 1 per segment, 1–3 mm. Spores mostly abortive, some viable. 2n = 144.


Habitat: Limestone rocks in shaded forests
Elevation: 0–50 m

Discussion

Asplenium plenum occurs with its parents on limestone rocks in shaded forests and is known only from Florida, although it could occur in the Antilles, Central America, and South America (D. B. Lellinger 1981). It is noteworthy for constituting one of the first known examples of backcrossing and formation of a new taxon by unreduced spores from a sterile hybrid. According to V. M. Morzenti (1967) and G. J. Gastony (1986), hybridization between A. abscissum and A. verecundum produced A. × curtissii. An unreduced spore of the hybrid gave rise to a 3 x gametophyte. This gametophyte produced a 3 x sperm that backcrossed with an x egg of A. abscissum producing the 4 x allotetraploid, A. plenum, that is not only capable of propagation by minute root proliferations like those of the parents but also to some extent by spores. This complex hypothesis was confirmed by electrophoretic comparisons of the plants involved (G. J. Gastony 1986).

Selected References

None.

Lower Taxa

None.
... more about "Asplenium plenum"
Notched (?) +  and Pointed (?) +
narrowing +
Warren H. Wagner Jr. +, Robbin C. Moran +  and Charles R. Werth +
E. P. St. John ex Small +
not tapered +
simple +  and 4-pinnate +
12 cm120 mm <br />0.12 m <br /> (15 cm150 mm <br />0.15 m <br />) +
8 cm80 mm <br />0.08 m <br /> (12 cm120 mm <br />0.12 m <br />) +
lanceolate +
thin;1.5cm;5cm +
Ruffled spleenwort +
0–50 m +
Limestone rocks in shaded forests +
monomorphic +
fertile +  and than sterile ones +
entire +  and denticulate +
perforate +, reticulate +, spiny +  and winged +
not articulate +
6 cm60 mm <br />0.06 m <br /> (10 cm100 mm <br />0.1 m <br />) +
1/4 length of blade;2/5 length of blade +
c--shaped +
2 cm20 mm <br />0.02 m <br /> (6 cm60 mm <br />0.06 m <br />) +
1 cm10 mm <br />0.01 m <br /> (3.5 cm35 mm <br />0.035 m <br />) +
0.5 cm5 mm <br />0.005 m <br /> (1.8 cm18 mm <br />0.018 m <br />) +
linear;oblong +
0.4 cm4 mm <br />0.004 m <br /> (1 cm10 mm <br />0.01 m <br />) +
Ferns S. E. States +
blackish +  and green +
proliferous +
0.04 cm0.4 mm <br />4.0e-4 m <br /> (0.11 cm1.1 mm <br />0.0011 m <br />) +
deltate +
0.3mm;0.7mm +
less lunate;linear +
0.1 cm1 mm <br />0.001 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
dorsiventral +  and symmetric +
Asplenium plenum +
Asplenium +
species +
anastomosing +
not conspicuous +