Redhead Fungal Biogeography.pdf - Mushroom Hobby

Can. J. Bot. Downloaded from www.nrcresearchpress.com by Adolf Ceska on 10/11/11
For personal use only.
3004 CAN. J. BOT. \
in 1983 (Redhead 1984b), i.e., coast to coast in 5 years. This
pattern of distribution certainly brings to mind the anonymous
quote cited in Smith and Weber (1980, p. 6), "Mushrooms are
where you find them." The apparent hopelessness of studying
the biogeography of mushrooms, as well as economical practices,
have been contributing factors leading to the common
practice of citing mushroom specimens in North American
monographs by the state or province followed only by
collector's numbers and no maps. For example, Lactarius
glyciosmus (Fr.) Fr. was reported from unspecified locations
in both Quebec and Ontario in addition to various other provinces
and states by Hesler and Smith (1979). Ontario covers
1 068 630 km2 and Quebec covers 1 540 681 km2, both span
nearly 15" of latitude, and both have vegetation ranging from
tundra to Carolinian hardwood forests.
In questions of plant quarantine, legal issues concerning trafficking
of illicit species, locating or protecting harvestable species,
and in the formulation of national policies, it is
imperative that some sense be made of the distributional patterns
of macrofungi. Are there species truly endemic to Canada
and not just known from a type locality in Canada? If a species
is found in coniferous forests in British Columbia, and then in
New York state, can we assume it occurs across the continent?
If a fungus, new to North America, is found in Canada, where
else in the world might it have been described? What were the
mycofloristic elements that combined to form our present
fungus flora?
Comparable plant and lichen floras
During the Pleistocene nearly all of Canada (Prest 1984),
except for parts of the northern Yukon and the Arctic Archipel-
ago (HultCn 1937), isolated parts of coastal British Columbia
(Calder and Taylor 1968), and perhaps Newfoundland (Ahti
1983; Brassard 1983, 1984; Steele 1983), was covered by con-
tinental glaciers. In the past 8000 - 12 000 years, virtually all
of Canada has been recolonized from elsewhere. HultCn (1937)
suggested that some of the northern vascular plant flora of
North America and Eurasia survived in isolated refugia, such
as those mentioned above, from which they are radially
spreading at different rates. Whitehead (1972) noted that much
of the northern flora was displaced to the south, to form plant
communities that differed from any extant flora. Some plant
species have successfully recolonized circumpolar areas and
others now have fragmented, disjunct distributions. Commonly
recognized disjunctions among vascular plants are the eastern
Asia - eastern North American disjuncts (Gray 1859; Wood
1972), eastern North America - western North America dis-
juncts (Schofield 1969; Wood 1972), amphi-Atlantic disjuncts
(HultCn 1958), and amphitropical North America - South
America disjuncts (Wood 1972). Culberson (1972), Schofield
and Crum (1972), and Schofield (1972) have shown that
lichens and bryophytes have nearly identical patterns of dis-
junctions and contiguous ranges to those exhibited by vascular
plants. Culberson (1972, p. 165) stated, "So similar in fact
are the well documented ranges of lichens to the ranges
of vascular plants that the conclusion that both result from
the same physioecological and historical factors is inescap-
able." With regard to the Canadian vascular plant flora,
Porsild (1958) recognized eight major categories of plant
distribution with additional subcategories: (i) Circumpolar
(High-arctic Element, Arctic-alpine Element, Low-arctic Ele-
ment); (ii) Amphi-Atlantic (Arctic Element, Subarctic Ele-
ment); (iii) Amphi-Beringian, (iv) North American (Arctic
Element, Boreal forest Element, Cordilleran Element, Pacific
coast Element, Prairie and foothill Element, Southern hard-
wood forest Element, Northern hardwood forest Element,
Atlantic coastal plain Element); (v) Arctic Archipelago
Endemic; (vi) Eastern Arctic Endemic Element; (vii) Western
Arctic Endemic Element; (viii) Disjuncts. The disjunct distri-
butions in North America can be further divided as done by
Schofield and Crum (1972) for bryophytes. They recognized
eastern American - East Asia disjuncts, tropical and sub-
tropical - Southern Appalachian disjuncts, bipolar disjuncts,
European - western North America disjuncts, as well as
amphi-Pacific, amphi-Atlantic, and arctic-alpine disjuncts.
Brodo and Hawksworth (1977) categorized the distributional
patterns of various epiphytic North American lichen genera
slightly differently. They treated many of the disjuncts as spe-
cies with fragmented circumboreal ranges, and therefore,
included them with species with more complete circumboreal
distributional patterns. Thus, their categories were (i) Circum-
boreal -Circumpolar species (1. arctic-alpine element; 2. low-
arctic element; 3. amphi-Atlantic, southern element; 4. boreal
forest element; 5. Appalachian - Great Lakes, temperate; 6.
oceanic-suboceanic species; 7. western American - Euro-
pean disjuncts); (ii) Asian affinities (8. bicoastal, Appala-
chian - west coast disjuncts); (iii) North American endemics
(9. North Pacific; 10. coastal lowland; 11. lowland to western
montane humid forests; 12. Western montane and inter-
montane dry forests; 13. Appalachians; 14. northeastern
coastal plain; 15. Central American highlands).
Current status of macromycete mycogeography
Relatively few studies have been made of the distributions of
macromycetes. Accumulation of accurate data is the most
common problem. With fleshy fungi, detailed field notes are
often required for precise determinations. Hence, relatively
few herbarium specimens can be confirmed or redetermined
accurately. The need for detailed notes slows the collecting
process so that fewer collections are made. Added to these
problems is the ephemeral nature of the fruitbodies. Another
consideration of more importance in Eurasia than in North
America, is the limitation of access by political boundaries.
The latter factor severely limited the usefulness of maps of 50
macromycetes prepared by the Committee for Mapping of
Macromycetes in Europe (Lange 1974) and the two earlier
maps by the committee- a an sen and Lange 1966). Contribu-
tions were lacking from Spain, Portugal, Italy, and the USSR,
and relatively few were received from Bulgaria and Ireland. To
a lesser extent this occurs in North America. Kers (1988)
mapped the disjunct European - western North American dis-
tribution for the hypogeous ascomycete Geopora cooperi
Hark. The species appears to abruptly stop at the border
between Washington, U.S.A. and British Columbia, Canada,
and again reappears in Alaska. This is clearly an artifact result-
ing from monographers collecting only within their own
country. Canadians have not collected many hypogeous fungi.
To overcome some of the difficulties mentioned above, the
European Mycological Congress chose 100 easily recognized,
clearly defined macrofungi, e.g., Auriscalpium vulgare S. F.
Gray, Strobilomyces floccopus (Vahl. : Fr.) Sacc., and
Phaeolepiota aurea (Bull. : Fr .) Marie for mapping (Lange