History of Name:
Laccaria longipes
G. M. Mueller, Mycotaxon 40: 145-150. 1991. Type: CANADA: Ontario, Nipissing District,
Algonquin Provincial Park, Spruce Bog Trail, among Sphagnum under Picea
mariana, Larix laricina and Alnus rugosa, 18 September 1984, G. M.
Mueller 1929 (F!, holotype).
Species synopsis:
Pileus mostly 11-55 mm broad, translucent striate, orange brown. Lamellae light flesh
color. Stipe 67-138(-165) mm long; basal mycelium white. Basidia 4-sterigmate. Cheilocystidia
absent. Basidiospores 7-8.5 X 6-8 µm (excluding ornamentation), subglobose to
broadly ellipsoid, echinulate; spines mostly <0.5-1.5 µm long. Great Lakes
region among moss, especially Sphagnum.
Habitat and Distribution:
Among mosses, especially Sphagnum, usually under Picea mariana (Mill.)
B. S. P., Larix laricina (Du Roi) K. Koch and Alnus rugosa (Du Roi)
Spreng. Reported to date from the Great Lakes region (southern Ontario, Michigan,
Wisconsin Minnesota) and New York. See Specimens
Examined for the list of species studied.
Observations:
Laccaria longipes can be distinguished from other members of the L. laccata
complex by its relatively small, subglobose basidiospores, long stipe, and restricted
habitat. Laccaria laccata var. moelleri also occurs in bogs and has
similar macromorphological features but differs in having larger basidiospores (
= 8-10 x 7.3 8.3 µm). Laccaria galerinoides Singer is another taxon which
grows among Sphagnum. It appears to be restricted to southern Argentina and
Chile and has only been reported from under Nothofagus antarctica (G. Forster)
Derst. Laccaria galerinoides differs from the two Northern Hemispheric taxa
in having smaller, darker colored basidiomata and more elongate basidiospores ( =
1.34; holotype).
Tested isolates of L. longipes were intersterile with all other tested isolates
of the L. laccata complex including isolates of L. laccata var. moelleri
(Mueller, 1991b, 1991c). RFLPs of mtDNA and rDNA indicate that divergence has occurred
between L. longipes and other taxa in the L. laccata complex (Gardes
et al., 1990, 1991a). While isolates of L. laccata var. moelleri
were intersterile with all tested North American isolates, including L. laccata
var. pallidifolia (intersterility group 1), they were intercompatible with
the tested Swedish isolates of L. laccata var. pallidifolia and both
taxa belong to intersterility group 3 (Mueller and Vellinga, 1986; Mueller, 1991b,
1991c). Data on potential molecular divergence between these morphologically distinct
taxa do not yet exist, however, since both isolates of intersterility group 3 tested
by Gardes et al. (1990, 1991a) are referable to L. laccata var. moelleri.
Collections of L. longipes were cited as L. laccata var. moelleri
in several recent publications (Doudrick and Anderson, 1989; Gardes et al.,
1990, 1991a). The decision to treat the North American and Swedish populations as
distinct taxa occurred only after a synthesis of the data on RFLPs with data on intercollection
pairing reactions and morphometric similarities (Mueller, 1991b, 1991c).
It is not yet clear whether L. longipes and L. laccata var. moelleri
are closely related or if their similar macromorphology is due to convergence
resulting from their occurrence among Sphagnum and other mosses.
Macromorphology:
Pileus 11-55(-78) mm broad, convex to broadly convex, often becoming plane
to uplifted, often centrally depressed, slightly to moderately translucent-striate,
finely fibrillose, orange-brown (6B5-6D7) fading to buff in age; margin incurved
to decurved or plane, entire to undulate, becoming slightly eroded. Lamellae
adnate, distant, thick, up to 10 mm broad, light flesh color (near 6A2). Stipe
67-138(-165) x 3-9 mm, equal with slightly swollen base or narrowly clavate, dry,
slightly to moderately fibrillose striate, concolorous with pileus. Basal mycelium
white. Basidiospores in mass white.
Micromorphology:
Pileipellis of radially arranged barrel-shaped hyphae with occasional, scattered
small fascicles of 10-30 ± perpendicular hyphae; terminal cells 5-10 µm,
morphologically undifferentiated to subclavate, hyaline. Pileus trama tightly
interwoven, morphologically undifferentiated, hyaline to light yellowish brown. Lamellar
trama of parallel to subparallel hyphae, mostly 3-19 µm diam, thin-walled,
hyaline; cells barrel-shaped. Subhymenium morphologically undifferentiated.
Basidia 28-44 x 7-10 µm, clavate, hyaline; sterigmata 4, up to 10 µm
long. Pleurocystidia lacking. Cheilocystidia not observed. Basidiospores
(excluding ornamentation) [158\7] 7-8.5(-9) x 6-7.8(-8.4) µm ( = 7.6-7.8 x 6.8-7.2
µm), Q = (1-)1.05-1.2(-1.3) ( = 1.08-1.13), subglobose to broadly ellipsoid,
occasionally globose or ellipsoid, hyaline, echinulate; echinulae (0.7-)1-1.5(-2)
µm long, less than 1 µm wide at base.
Somatic Culture Mat Morphology
(n=1; GMM 1929):
PDA: Radius at week 6 = 43 mm; mat felty, thick, tightly interwoven,
tightly appressed to agar surface, not translucent, uniform texture near plug, forming
dendritic thicker strands from midpoint to margin, tan to olive brown; margin
* 6 mm broad, subfelty to silky, abruptly thinner than mat, tan; hyphae 2.5-5
µm diam, morphologically undifferentiated. MMN: Radius at week 6 = 28
mm; mat felty, thick, tightly interwoven, tightly appressed to agar surface,
uniform texture, dull white; margin up to 5 mm broad, irregular, white; hyphae
2.5-8 µm diam, morphologically undifferentiated, occasionally irregularly swollen.
MEA: Radius at week 6 = 42 mm; mat subfelty, thin, translucent, white;
margin 2-3 mm broad, not well differentiated, white; hyphae 2.5-8 µm
diam, most morphologically undifferentiated, occasionally irregularly swollen.