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The Genera Boletellus and Austroboletus  

[ Basidiomycetes > Boletales > Boletaceae . . . ]

by Michael Kuo

The genera Boletellus and Austroboletus are easy to distinguish from the other boletes--if you have a microscope. These genera are composed of species with spores that are not smooth, which is unusual among boletes. In Boletellus, the spores are ornamented with ridges, while spores in Austroboletus are pitted. Another bolete genus, Strobilomyces, includes species with spiny spores, but Strobilomyces species are easily separated from other boletes without using a microscope.

If you do not have a microscope, most of the dozen or so mushrooms in Austroboletus and Boletellus are difficult to separate from boletes in other genera. However, Austroboletus betula, Boletellus russellii, Austroboletus subflavidus, and Boletellus ananas can probably be fairly quickly assessed with careful perusal of photographs (click each link for a photo, and be sure to pay attention to the stems).

Whether or not Boletellus and Austroboletus are "good" genera is a question I will leave to the specialists. Mycologists have never agreed on precise limits for these groups, and we have seen plenty of evidence in recent years that sporal ornamentation in and of itself does not necessarily correlate to actual genetic difference. However, separating these mushrooms is very useful--at least, to those who have microscopes--when it comes to identifying (rather than classifying) them.

 		 

Boletellus russellii
Ridged spores of Boletellus russellii

Austroboletus gracilis
Pitted spores of Austroboletus gracilis

Boletellus pseudochrysenteroides spores
Ridged spores of Boletellus pseudochrysenteroides


Key to 11 Bolete Taxa with Pitted or Ridged Spores  


1.Stem shaggy, coarsely and conspicuously reticulate, or conspicuously ridged.
2

1.Stem fairly smooth, or finely reticulate.
7


2.Pore surface bruising blue.
3

2.Pore surface not bruising blue.
4


3.Usually growing on the ground; stem and mature cap conspicuously scaly; cap medium brown to dark brown; stem not bruising.
Boletellus fallax

3.Usually growing on rotting wood; stem hairy and dotted, cap smooth becoming cracked; cap blackish brown becoming brown; stem bruising blue, then slowly reddish.
Boletellus chrysenteroides
in Smith & Thiers, 1971


4.Spore print olive to olive brown.
5

4.Spore print pinkish brown to reddish brown.
6


5.Cap smooth, slimy when wet, shiny when dry; spores pitted and loosely reticulate.
Austroboletus betula
in Smith & Thiers, 1971
(photo at Southern Appalachian Fungi)

5.Cap velvety and dry; spores grooved and ridged.


6.Cap whitish to pale grayish yellow; taste bitter.
Austroboletus subflavidus
at Roger's Mushrooms

6.Cap reddish brown to brown; taste mild.
Austroboletus gracilis var. pulcherripes


7.Pore surface whitish at first, becoming pinkish to flesh-colored at maturity; stem usually graceful and slender.

7.Mature pore surface yellowish to bright yellow; stem variously shaped but not typically graceful and slender.
8


8.Cap pinkish to reddish, with very conspicuous, large, hairy scales; partial veil present when young.

8.Cap variously colored but not covered with large, conspicuous hairy scales; partial veil absent.
9


9.Cap blackish brown to brown, without reddish shades; usually growing on decaying wood.
Boletellus chrysenteroides
in Smith & Thiers, 1971

9.Cap reddish, at least when young; usually growing on the ground.
10


10.Cap remaining reddish overall through maturity; taste acidic.

10.Cap reddish when young but soon olive brown to olive gray; taste mild.
Boletellus intermedius
in Smith & Thiers, 1971



References

Arora, D. (1986). Mushrooms demystified: A comprehensive guide to the fleshy fungi. Berkeley: Ten Speed Press. 959 pp.

Bessette, A. E., Roody, W. C. & Bessette, A. R. (2000). North American boletes: A color guide to the fleshy pored mushrooms. China: Syracuse UP. 399 pp.

Both, E. E. (1993). The boletes of North America: A compendium. Buffalo NY: Buffalo Museum of Science. 436 pp.

Coker, W. C. and Beers, A. H. (1943). The boleti of North Carolina. New York: Dover. 96 pp. (1971 reprint.)

Grund, D. W. & Harrison, A. K. (1976). Nova Scotian boletes. Germany: J. Cramer. 283 pp.

Smith, A. H. & Thiers, H. D. (1971). The boletes of Michigan. Ann Arbor: U Michigan P. 428 pp. An online version of this book is available here, at the University of Michigan Herbarium (URL too long for duplication).

Smith, A. H., Smith, H. V. & Weber, N. S. (1981). How to know the non-gilled mushrooms. Dubuque, Iowa: Wm. C. Brown. 324 pp.

Snell, W. H. & Dick, E. A. (1970). The boleti of northeastern North America. Germany: J. Cramer. 115 pp.

Wolfe, C. B. (1979). Austroboletus and Tylopilus subgenus Porphyrellus with emphasis on North American taxa. Germany: J. Cramer. 148 pp.



Cite this page as:

Kuo, M. (2005, March). The genera Boletellus and Austroboletus. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/boletellus.html

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