Major Groups > Boletes > Boletellus, Heimioporus & Austroboletus

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The Genera Boletellus, Heimioporus, and Austroboletus  

[ Basidiomycetes > Boletales > Boletaceae . . . ]

by Michael Kuo

These genera are easy to distinguish from the other boletes--if you have a microscope. They contain 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 and spores in Hemioporus are pitted or reticulate. Another bolete genus, Strobilomyces, includes species with spiny, reticulate spores, but Strobilomyces species are fairly 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, Heimioporus, and Boletellus are difficult to separate from boletes in other genera. However, Heimioporus betula, Boletellus russellii, Austroboletus subflavidus, and Boletellus ananas can probably be fairly quickly assessed with careful perusal of photographs (click each link for photos, and be sure to pay attention to the stems).

Whether or not Boletellus, Heimioporus, and Austroboletus are "good" genera is up for grabs. 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. Researchers at the New York Botanical Garden are currently sorting out some of these boletes (see Surveys and Revisions in Boletineae for links to ongoing studies of Boletellus and Heimioporus). However, separating these mushrooms is very useful--at least, to those who have microscopes--when it comes to identifying (rather than classifying) them.

 		 

Austroboletus gracilis
Pitted spores of Austroboletus gracilis

Boletellus pseudochrysenteroides
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.Stem and mature cap conspicuously scaly; growing terrestrially.
Boletellus fallax

3.Stem hairy and dotted, cap smooth becoming cracked; often (but not always) growing from or near rotting oak stumps.


4.Spore print olive to olive brown.
5

4.Spore print pinkish brown to reddish brown.
6


5.Cap smooth, moist to slimy when wet, shiny when dry; stem yellow, becoming reddish with age; spores pitted.

5.Cap velvety and dry; stem reddish brown, without a yellow stage; 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; often (but not always) growing from or near rotting oak stumps.

9.Cap reddish, at least when young; growing terrestrially.
10


10.Cap remaining reddish overall through maturity; taste acidic; most spores > 11 µ long.

10.Cap reddish when young but soon olive brown to olive gray; taste mild; most spores < 12 µ long.
Boletellus intermedius
in Smith & Thiers, 1971



References

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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