Monographs Details: Merugia palicoureae Rogerson & Samuels
Authority: Samuels, Gary J. & Rogerson, Clark T. 1990. New ascomycetes from the Guayana Highland. Mem. New York Bot. Gard. 64: 165-183.
Description:Species Description - Stroma superficiale, tenue, crustosum, nigrum,
usque 1 m m diam., annulis concentricis. Perithecia
centralia, ovoidis vel subglobosa, non
papUlata, nigra, verrucosa, cuqusque 2-5. Asci
cylindrici, 125-170 x 12-13 µm, apice annulo
chitinoideo provisi. Ascosporae filiformes, 98-
120 X 3-4.5 Mm, 0-6-septatae, hyalinae. Pycnidia
prope stromatis marginem immersa; cellulae
conidiogenae iis Chalarae-similis, in hymenio
basali productae; conidia clavatae,
dacryoidae, vel oblongae, 6.2-7.4(-8.7) x 2.8-3
fim, unicellulariae, hyalinae.
Stroma superficial, ca. 135 µm at thickest point
in the middle, crustose, easily removed from the
substrate, black, to 1 m m diam., with concentric
rings; stromal surface ca. 20 fim wide, of dichotomously branched, short-celled, 5-7 µm
wide, darkly pigmented hyphae; cells immediately
below the surface angular, ca. 7.5 µm across,
darkly pigmented, forming a region ca. 40 iim
wide; stromal cortex ca. 75 µm wide at the widest
Distribution and Ecology - Guyana, known only from the type collection.
Habitat. O n stems and petioles of Palicourea
Etymology of the Specific Epithet. Refers to
the host plant.
TYPE. GUYANA: Mt. Wokomung, at base of exposed
rock wall of main peak, 05°05'N, 59º50'W, elev.
1540-1570 m, on petioles and stems of Palicourea sp.
(Boom 9211), 15 Jul 1989, Samuels (6552), Boom &
Bacchus (holotype N Y , isotype BRG).
Notes. We have referred Merugia palicoureae
to the Lasiosphaeriaceae because the ascal ring,
which is inamyloid and chitinoid, resembles the
apical ring of other members of that family
(Lundqvist, 1972; Eriksson & Yue, 1989), and
because of the persistent, apically free paraphyses,
and long, colorless ascospores. The asci are
freed from the hymenium and are presumably
discharged intact; very few discharged ascospores
The anamorph, with conidia formed within
collarettes of Chalara-like phialides, is not inconsistent
with the Phialophora anamorphs attributed
to some species of Lasiosphaeria (Gams
& Holubova-Jechova, 1976). A n attempt to germinate
ascospores of Merugia palicoureae on
commeal dextrose agar at 20°C was unsuccessful.
The intimate association ofthe pycnidia with the
perithecia leaves no doubt that the two morphs
are part of the same life-cycle. This anamorph
cannot be identified to any ofthe genera included
by Sutton (1980), but it can be accommodated
in the anamorph order Phialidales suborder Phialostromatineae,
as defined by Sutton (1980).
Stromata of Merugia palicoureae are not
erumpent; they are easily removed from the substrate.
There is no evidence of direct penetration
of the apparently healthy tissues of the Palicourea.
However, the dark porose cells that form in
a single layer at the stromal base adjacent to the
host tissue (Fig. 7) are reminiscent of appressoria
formed by species of Colletotrichum (Sutton,
1980: fig. 320)