Details about map content are available here Click on the map dots to view record details.
Species Information
Summary: Features include 1) erumpent growth on aspen and sometimes other hardwoods, 2) cankers that are crusty, cracked, and white-pruinose then black, the cankers having gray perithecia and gray dusty conidial pegs between bark and cambium, 3) not exuding pigments when a small piece is placed in 10% KOH on a microscope slide, 4) a germ slit on the concave side of the spore, and immature spores bearing a cellular appendage, and 5) the ascus tip containing an amyloid plug clearly visible at 400x. In eastern North America, "Hypoxylon canker is a very important and damaging disease of aspen, especially in stands predisposed by weather or insect damage", but in BC it is infrequently collected and has not been associated with heavy damage within stands, (Callan).
Entoleuca mammata has been found in BC, WA, ON, NF, AK, CO, IA, MA, ME, MI, MN, MO, ND, NH, NJ, NY, PA, VA, WI, WY, Finland, Germany, and Sweden, (Miller, J.H.).
Fruiting body: stromata [fruitbodies] "immersed or erumpent from bark", on plants with thick hard bark discrete, orbicular [circular], 0.2-0.5cm across and 0.1-0.2cm thick, while on plants with soft bark often indefinite in shape and usually coalescing to form an effused fruitbody up to 2.5cm in length; "at first white pruinose, later becoming black"; "smooth except for the coarsely papillate ostiola, or often tuberculate from the prominent perithecial projections, carbonous", perithecia single to many, up to 30 in a stroma, (Miller, J.H.), cankers "begin as yellow to orange, slightly sunken areas of bark on lower trunks or branches", then "expand more rapidly longitudinally than horizontally, the surface becoming roughened or cracked", after a few years, "cankered bark starts to separate from the underlying wood", as gray, dusty pillars of fungal tissue (hyphal pegs) 0.2-0.5cm in diameter, and 0.1-0.2cm tall, covered with conidia, force the bark outward; perithecia develop in whitish to grayish crusts "on dark central areas of the canker, where bark has split or sloughed off", clusters of 10-30 perithecia may be fused into a single crust, with the top of each perithecium nipple-like, opening with darker central ostiole; interior black and shiny when a fresh, dry crust is sectioned, (Callan)
Microscopic: SPORES 20-33 x 9-12 microns, oblong-elliptic with obtuse ends, dark brown, uniseriate or obliquely uniseriate; ASCUS 140-200 x 12-16 microns in spore-bearing part, cylindric, with stem 30-40 microns long; PARAPHYSES present; PERITHECIUM 700-1000 microns in diameter, spherical to ovate, (Miller, J.H.), SPORES 20-33 x 9-12 microns, elliptic, with one side flattened, blackish brown, with straight germ slit appearing under high magnification as a pale line on the concave side of the spore; ASCUS 8-spored, cylindric, long-stemmed, with prominent rectangular plug that turns blue in Melzer''s reagent; CONIDIUM 5.5-8.0 x 1.5-4.0 microns, single-celled, colorless, (Callan)
Habitat / Range
"Hypoxylon cankers occur most commonly on Populus tremuloides, but are also rarely encountered on Salix spp. and Alnus sinuata (Regel) Rydb. (Sitka alder) in BC"; perennial and thus detected any time of year, new cankers appearing after stress or wounding, (Callan, Latin names italicized), on wood: Acer (maple), Alnus (alder), Betula (birch), Carpinus (hornbeam), Fagus (beech), Picea (spruce), Populus, Pyrus (pear), Salix (willow), Sorbus (mountain-ash), Ulmus (elm), (Miller, J.H.), a serious pathogen of Populus tremuloides (Quaking Aspen) and a number of other species of Populus, Alnus, Salix, Betula, and other genera, (Rogers)
Similar Species
Entoleuca callimorpha Syd. is described in Rogers, J.D.(5) and collections were examined from Montana and Colorado; as far as they knew it had not been collected in recent times: 1) the ascospores averaged much smaller, (14.5)17.5-20.5(22.0) x (6.5)7.0-9.5 microns, than for Entoleuca mammata, 2) spore shape is elliptic to elliptic-inequilateral, with narrowly rounded or broadly rounded ends (as opposed to somewhat rectangular for Entoleuca mammata), (Rogers, J.D.(5)). |E. mammata differs from Hypoxylon spp. in several ways including 1) the stroma does not exude pigments when a small piece is placed in 10% KOH on a microscope slide or watch glass, 2) the ascospore germ slit occurs on the concave side of the pore whereas in Hypoxylon the slit is on the concave side if the spore is inequilateral, 3) immature ascospores bear a cellular appendage, 4) the "ascus tip contains a plug which turns blue in Melzer''s reagent, is taller than broad", and is clearly visible at 400x under a microscope, whereas Hypoxylon species "have much reduced disc-like ascus apical structures that are much broader than tall, and are often hard to see even at high magnification", and 5) the anamorph produces bark-rupturing hyphal pegs covered in conidia, unlike anamorphs of Hypoxylon species, (Callan, after Ju and Rogers(1996)).
