CRAPHIS ScnIPTA - Universitetet i Oslo

6 Marie Lindstrdnt
irregularly orientated, intenn oven hyphae and
photobiont cells; hyphae 2.5-3.5 pm thick.
Photobiont Nostoc; cells 6-8 x 3.5-5 Ffr,
ellipsoid or rarely globose, in short chains.
l,ower cortex similar to upper cortex, 6-17 pm
thick, occasionally with short rhizo-hyphae of
hyaline, cylindrical cells, 2.5-3.5 pm.
Apothecia zeorine with a narrow, poorly
developed, cupulate excipulum of periclinal
hyphae, best observed at the margins where it
is 35-47 pm thick. Thalline margin 45-65 pm
thick. Mature apothecia with prominent basal
and marginal supporting tissue of hyaline cortical
cells; at the margins 5-7 cells thick, 45-
%) pm thick, underneath the hymenium 8- 10
cells thick, 94-118 pm thick, distinctly paraplectenchymatous.
Subhymenial layer 45-95
pm thick, of closely compacted, irregularly
orientated hyphae, opsgu€, yellowish.
Hymenium 90-118 pm high. Epihymenium 6-
18 pm high, reddish-brown, pigment external
to apices of the paraphyses, paraphyses
conglutinated in a gelatinous matrix, 1-2.5 pm
thick below, apical cells 3.5 pm wide, septated.
Asci clavate to cylindrical, 71-100 x 9.5-1,4
pm. Ascospores mono- to distichous, hyaline,
usually ellipsoid to fusiform, occasionally with
acute apices and apiculi, 2L-25 x 8- 10 ,rzm
(length: mean value 23.2 Fn, SD 2.0 Ffr,
L.min. I7.7 Ffr, L.mar. 28.3 Fffi, n=90; width:
meanvalue 9.3 pm, SD 1.2 Ffr, W.min. 7.I pm,
W.ma)r. 1L.8 Ffr, n=90), eight per ascus,
usually more or less submuriform with 3 (-5)
transverse septa, 1 longitudinal septum (rarely
without longitudinal septum). Epispore c. I pm
thick, usually more or less smooth, sometimes
minutely pitted.
Pycnospores hyaline, bacillariform, c. 3.5 x
0.5-L.0 pm.
Distribution, habitat and ecoloEr
Leptogium degefii is a neotropic species with,
as far as knowo, & very limited distribution in
French Guyana. Unfortunately I have no own
field experience of this new taxon, and the
notations on habitat and ecology are usually
very scanty. However, it seems to be more or
less restricted to the primary lowland rainfor-
GRAPHTS SCRIPTA 5 (1ee3)
est in the central and southern parts of French
Guyana.
Leptogium degelii is a corticolous species
and has been collected on the trunk and
branches of various trees (e.g. Theobroma),
and lianas. One of the specimens (Jacquemin
2329) was found growing submerged
(presumably on rocks) in the Qapock River.
L. degelii grows usually intermingled with
bryophytes and other lichens, occasionally with
filmy ferns. Sometimes it is associated with
other species of Leptogium, vrz. L. (uureum
(S*.) Mont., L. diaphanum (S*.) Mont., and
L. reticulatum Mont.
The altitudinal distribution ranges from c.
35 m to 200-300 m.
Remarks
Leptogium degelii is characterized by the
thin, papyraceous thallus with a roughened,
matt and weakly bullate-faveolate upper surface,
the shortly stipitate apothecia with small
irregular, granular to terete appendages on the
thalline margin. L. degelii seems to have a
more or less constant morphology. Some variation
is observed in the colour of lobes and
apothecia. This new species belong to the
Leptogium azureum group since the anatomy
and ontogeny of the apothecia and the spores
agrees well with that of L. azureum. L. degelii
is easily separated from L. azureum by smaller,
thinner and spreading lobes, matt, bullatefaveolate
upper surface, the thalline margin
with irregular appendages, and ascospores with
a more or less smooth epispore.
Additional specimens examined; French
Guyana. River Comt4: between Belizon and
Jalbot, M'15'N, 52"38'W, 35 m, L3 June 1.958,
Degelius s.n. pro ma(. parte (Herb. Degelius);
Saiil, near Boeuf Mort, 03'38'N, 53"L2'W,
200-300 m, March 1985, Aptroot 15243 pro
parte, 15345 (U); Saiil, near Roche Bateau,
03"38'N, 53"10'W, 200-300 m, March 1985,
Aptroot 15392, 15444 (U); Trois Sauts,
Oyapock, 02'15'N , 52"40'W, 16 March 1979,
Jacquemin 2329 (U).