Pleosporales - CBS - KNAW
Pleosporales - CBS - KNAW
Pleosporales - CBS - KNAW
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Fungal Diversity<br />
Fig. 77 (continued)<br />
Literature: Ramaley and Barr 1995.<br />
Type species<br />
Pleoseptum yuccaesedum A.W. Ramaley & M.E. Barr,<br />
Mycotaxon 54: 76 (1995). (Fig. 79)<br />
Ascomata 300–500 μm diam., scattered, or in small<br />
groups of 2–3, immersed with a flattened top, globose to<br />
conoid, black, papillate, ostiolate (Fig. 79a). Papilla<br />
small, slightly protruding from the host surface. Peridium<br />
30–50 μm thick at sides, up to 100 μm thick at the apex,<br />
1-layered, composed of 5–8 layers of heavily pigmented<br />
purplish-brown cells of textura angularis, cells 5–12 μm<br />
diam., cell wall 1–2 μm thick, apex cells smaller and<br />
walls thicker (Fig. 79c). Hamathecium of dense, long<br />
cellular pseudoparaphyses 1–2 μm broad, septate,<br />
branching (Fig. 79b). Asci 125–170(−195)×15–22 μm<br />
(x ¼ 153:8 19:3mm, n=10), 8-spored, bitunicate, fissitunicate,<br />
cylindrical to cylindro-clavate, with a short,<br />
narrowed, furcate pedicel which is 10–20 μm long, with<br />
an ocular chamber best seen in immature asci (to 5 μm<br />
broad×3 μm high) (Fig. 79d and e). Ascospores 22–30×<br />
11–14 μm (x ¼ 27:1 12:6mm, n=10) obliquely uniseriate<br />
and partially overlapping, ellipsoid, ovoid to fusoid,<br />
yellowish to yellowish brown, becoming reddish brown<br />
to dark brown, muriform, with 3-(4) transverse septa,<br />
constricted at the primary septum, part above central<br />
septum wider, vertical septa exist in each cell, ornamentation<br />
of foveolae in linear rows (Fig. 79f and g).<br />
Anamorph: Camarosporium yuccaesedum Fairm.<br />
(Ramaley and Barr 1995).<br />
Conidiomata 200–450 μm diam., pycnidial, immersed,<br />
scattered, subglobose to conoid, ostiolate. Macroconidiogenous<br />
cells determinate or indeterminate, enteroblastic,<br />
hyaline, smooth. Macroconidia holoblastic, 20–36×10–<br />
15 μm diam., ellipsoid to narrowly ovoid, muriform,<br />
yellowish brown, 3–7 transverse septa, constricted at the<br />
septa. Microconidiogenous cells produced near or in the<br />
ostiole, hyaline, smooth. Microconidia 5–10×5–7 μm<br />
diam., globose to ovoid, aseptate, hyaline, smooth.<br />
Material examined: USA, Colorado, Montezuma County,<br />
hillside near entrance to Mesa Verde National Park, on dead<br />
leaves of Yucca baccata, 11 Oct. 1992, Ramaley Annette<br />
(9237A) (BPI 802381, holotype).<br />
Notes<br />
Morphology<br />
Pleoseptum is a monotypic genus established by<br />
Ramaley and Barr (1995) and represented by P. yuccaesedum<br />
basedonits“immersed ascomata, thick peridium,<br />
muriform ascospores, anamorphic stage and the linoeate<br />
ornamentation of the ascospores and conidia”. Theshape<br />
of ascomata of Pleoseptum is comparable with that of<br />
Chaetoplea, but the peridium structure easily distinguishes<br />
them. Some species of Curreya, Leptosphaeria and<br />
Heptameria are comparable with Pleoseptum, but their<br />
anamorphic stages differ.<br />
Pleoseptum yuccaesedum and its Camarosporium yuccaesedum<br />
anamorph both formed in the leaves of Yucca<br />
baccata and the ascomata and conidiomata were indistinguishable.<br />
Camarosporium is the anamorph of diverse<br />
teleomorph genera included in Botryosphaeriales and<br />
Cucurbitariaceae (Kirk et al. 2008). The genus is in need<br />
of revision (Sutton 1980) and is no doubt polyphyletic.<br />
Phylogenetic study<br />
None.<br />
Concluding remarks<br />
The placement of Pleoseptum under Phaeosphaeriaceae<br />
is still tentative.<br />
Pleospora Rabenh. ex Ces. & De Not., Comm. Soc. crittog.<br />
Ital. 1: 217 (1863). (Pleosporaceae)<br />
Generic description<br />
Habitat terrestrial, saprobic or parasitic. Ascomata smallto<br />
medium-sized, immersed, erumpent to superficial,
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