Pleuridium ravenelii

Austin

Bull. Torrey Bot. Club 6: 142. 1877,.

Treatment appears in FNA Volume 27. Treatment on page 464.

Stem-leaves erect, concave, lamina juxtacostally 2-stratose, becoming 1-stratose towards margin; proximal leaves minute, bractlike, narrowly deltoid, acuminate, 0.53–0.85 × 0.15–0.25 mm, entire; distal stem-leaves ovate to lanceolate, acuminate to subulate, 1.05–1.75 × 0.2–0.38 mm, entire; costa broad, percurrent to excurrent. Sexual condition paroicous, antheridia naked in the distal leaf-axils just proximal to the perichaetium. Perichaetial leaves oblong to obovate-lanceolate proximally, carinate-acuminate distally, gradually narrowed to a broad, channeled to subtubulose acumen which generally shorter than the leaf base, 1.58–2.63 × 0.43–0.58 mm, margins serrulate to serrate, erect to incurved distally, coarsely and irregularly to distinctly jaggedly toothed at shoulder; lamina plicate to pleated; basal-cells oblong to rectangular; median cells subquadrate to shortrectangular; distal cells at shoulder longer, long-rhomboidal to curved linear; costa excurrent with a conduplicate or canaliculate awn, broad, smooth on back, indistinct at mid leaf, confluent with the juxtacostal part of lamina, filling most of the acumen; transverse-section of costa at mid leaf with adaxial guide cells and abaxial stereid cells forming wide rows across the width with the central accessory-cells forming an aperture; innermost perichaetial leaves ovate-acuminate, percurrent. Seta 0.15–0.2 mm. Spores (32–) 37.5–42.5 µm, bluntly and finely papillose, yellow to orange in mass.


Phenology: Capsules mature Mar–Jun.
Habitat: Bare sandy soil, open spaces of scrub oak association
Elevation: low to moderate elevations

Distribution

V27 673-distribution-map.gif

Ala., Ark., Del., Fla., Ga., La., Mass., Mo., N.J., N.C., Okla., Pa., R.I., S.C., Tex., W.Va.

Discussion

The chromosome number of Pleuridium ravenelii is n = 13 (North Carolina, H. A. Crum and L. E. Anderson 1981). The species is characterized by (1) plicate leaf lamina (most easily observed in transverse sections), (2) lamina outwardly 1-stratose but 2-stratose on either side of the costa, (3) channeled distal portion of costa, and (4) coarsely toothed shoulder. Serrations of the leaf shoulder, however, vary from minimally toothed with projecting ends of marginal cells to abruptly exaggerated (“jagged shoulders,” Crum and Anderson). Though not always obvious because of the plicate lamina and the canaliculate costa, the jaggedly toothed shoulders are most pronounced in outer perichaetial leaves. The spores are the largest in the genus, as initially described by Austin. Early American bryologists (e.g., S. Watson in W. H. Brewer et al. 1876–1880, vol. 2; C. L. Lesquereux and T. P. James 1884) considered P. ravenelii a taxon intergrading with P. acuminatum because of the intermediate leaf shape. Crum and Anderson suggested that P. ravenelii is an extreme habitat response of P. acuminatum populations along the coastal sand dunes of eastern North America. Most specimens examined are, indeed, from such characteristic habitats of the southeastern Coastal Plain. An occasional specimen may resemble P. acuminatum or P. subulatum in general habit. For instance, a specimen from Florida (Breen 2930, NY) has an ovate-lanceolate leaf base with narrowly acuminate tips and is 1-stratose in the portion of the lamina towards the margins (and is therefore close to P. subulatum), but (1) the carinate acumen (clearest in the characteristic transverse section), (2) the jagged teeth at leaf shoulders (usually obscure because hidden by the conduplicate costa and the plicate lamina), and (3) the juxtacostally 2-stratose leaf lamina support its identification as P. ravenelii.

Selected References

None.

Lower Taxa

None.
... more about "Pleuridium ravenelii"
to a broad , channeled to subtubulose acumen which generally shorter than the leaf base , 1.58-2.63×0.43-0.58 mm , margins +
0.158 cm1.58 mm <br />0.00158 m <br /> (0.263 cm2.63 mm <br />0.00263 m <br />) +
channeled +
broad +, 0.43mm +  and 0.58mm +
forming a marginal border +  and not differentiated +
Kwok Leung Yip +
Austin +
canaliculate +
oblong;rectangular +
serrulate +  and serrate +
to a broad , channeled to subtubulose acumen which generally shorter than the leaf base , 1.58-2.63×0.43-0.58 mm , margins +
0.158 cm1.58 mm <br />0.00158 m <br /> (0.263 cm2.63 mm <br />0.00263 m <br />) +
channeled +
broad +, 0.43mm +  and 0.58mm +
small +
cucullate +
orange;brownish +
cleistocarpous +
long-exserted +
ovoid +  and elliptical +
percurrent;excurrent +
subpercurrent +
shortrectangular +  and isodiametric +
monoicous +  and sexual +
long-rhomboidal +  and curved linear +
oblong;lanceolate +
0.105 cm1.05 mm <br />0.00105 m <br /> (0.175 cm1.75 mm <br />0.00175 m <br />) +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.038 cm0.38 mm <br />3.8e-4 m <br />) +
Ala. +, Ark. +, Del. +, Fla. +, Ga. +, La. +, Mass. +, Mo. +, N.J. +, N.C. +, Okla. +, Pa. +, R.I. +, S.C. +, Tex. +  and W.Va. +
low to moderate elevations +
Bare sandy soil, open spaces of scrub oak association +
1-stratose +  and 2-stratose +
plicate to pleated +
curved +  and straight +
3 (?) +  and 8 (?) +
subulate +, acuminate +  and lanceolate +
serrulate +  and serrate +
to a broad , channeled to subtubulose acumen which generally shorter than the leaf base , 1.58-2.63×0.43-0.58 mm , margins +
1.58mm;2.63mm +
undifferentiated +
channeled;channeled +
broad +, 0.43mm +  and 0.58mm +
conic +  and short-rostrate +
to a broad , channeled to subtubulose acumen which generally shorter than the leaf base , 1.58-2.63×0.43-0.58 mm , margins +
0.158 cm1.58 mm <br />0.00158 m <br /> (0.263 cm2.63 mm <br />0.00263 m <br />) +
toothed +, narrowed +, carinate-acuminate +, oblong +  and obovate-lanceolate proximally +
with a longer , broader sheathing base +  and differentiated +
0.043 cm0.43 mm <br />4.3e-4 m <br /> (0.058 cm0.58 mm <br />5.8e-4 m <br />) +
on short branches +  and axillary +
Capsules mature Mar–Jun. +
filamentous +
0.053 cm0.53 mm <br />5.3e-4 m <br /> (0.085 cm0.85 mm <br />8.5e-4 m <br />) +
0.015 cm0.15 mm <br />1.5e-4 m <br /> (0.025 cm0.25 mm <br />2.5e-4 m <br />) +
Bull. Torrey Bot. Club +
yellow;orange reddish-brown brown or reddish purple +
elongate +
0.015 cm0.15 mm <br />1.5e-4 m <br /> (0.02 cm0.2 mm <br />2.0e-4 m <br />) +
yellow +  and orange +
spherical +
branched +  and simple +
0.3 cm3 mm <br />0.003 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
superficial +
4 +  and 10 +
Pleuridium ravenelii +
Pleuridium +
species +
subulate +  and acuminate +
specialized +
synoicous +, paroicous +, autoicous +, dioicous +  and sexual +
plant +  and gregarious +
small +  and medium-sized +