Observation 97732: Loweomyces fractipes (Berk. & M.A. Curtis) Jülich

When: 2012-06-18

Collection location: Rock Island State Park, Warren Co., Tennessee, USA [Click for map]

35.8° -85.6346° 274m

Who: Christine Braaten (wintersbefore)

Specimen available

This is the third time I’ve found this fungus at three separate locations, and I think it is also the same one from my observation here: http://mushroomobserver.org/95685?q=Kgo9

Found each time on the smaller fallen branches of hardwoods. The pores are very small (2-4 per mm) becoming slightly larger near the stipe.

Spores are smooth, subglobose and lacrymoid with a single oil droplet, 4-4.5-5 x5-6-7.

This is seeming to be a fairly common mini-pored cream-colored stipitate polypore.


The larges fruitbody was approximately 8.0 cm.
Clamp connections seen on hyphae from the context of the pileus.
Clamp connections seen on hyphae from the context of the pileus.

Proposed Names

28% (1)
Recognized by sight: wild guess
31% (2)
Recognized by sight

Please login to propose your own names and vote on existing names.

Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
a lucky break
By: Danny Newman (myxomop)
2012-06-20 13:22:05 AEST (+1000)

There are madmen in dark, crooked, fairy tale towers agonizing over their own plain, pale, milquetoast polypores. We just happened to strike gold on MushroomExpert of all places. Good sleuthing all around. Huzzah!

So much for keys!
By: Christine Braaten (wintersbefore)
2012-06-20 13:16:17 AEST (+1000)

It looks exactly like https://www.google.com/...

I think Loweomyces fractipes (syn: Abortiporus fractipes) looks good,
Thanks Danny!

By: Danny Newman (myxomop)
2012-06-20 13:12:32 AEST (+1000)

means only generative hyphae. clamps are only present on generative hyphae, so if all the hyphae you see look pretty much the same and are all clamped, there’s a good chance it’s monomitic.

By: Danny Newman (myxomop)
2012-06-20 13:09:19 AEST (+1000)

from MycoBank (http://www.mycobank.org/...) as Abortiporus fractipes:

Abortiporus fractipes (Berk. & Curt.) Gilbn. & Ryv. Fig. 22 – North Am. Polypores 1:85. 1986. – Polyporus fractipes Berk. & Curt., Grevillea 1:39, 1872.

Basidiocarps highly variable, centrally to laterally stipitate, dimidiate with fanshaped to reniform pilei or almost effused-reflexed, 1-4 cm wide, 1-5 mm thick, soft when fresh, brittle when dry; upper surface white when fresh. with age and drying ochraceous to straw coloured, at first finely tomentose, with age more adpressed and semi-glabrous, often somewhat wrinkled, usually azonate; stipe when present white to ochraceous, up to 4 cm long, cylindric to flattened and expanded towards the pileus; pore surface white to cream, pores angular, 4-5 per mm, often decurrens on the stipe, but sharply delimited; context in pileus and stipe white and duplex with a hard inner or lower layer covered with a much looser layer which may be agglutinated on the surface with age; tube layer concolorous, up to 3 mm thick.

Hyphal system monomitic; generative hyphae with clamps, in the subhymenium and trama thin-walled, 3-5 µm in diam. in the context and especially the stipe much more thick-walled and reminiscent of skeletal hyphae, but with scattered clamps, and we interpret these hyphae as sclerified generative hyphae; also in the trama are some hyphae with contorted or lobed apices. Cystidia variably present. often difficult to observe, mostly close to the dissepiments, ventricose to cylindrical, thin-walled, 15-25 × 5-6.5 µm. Basidia broadly clavate. 4-sterigmate, 15-20 × 6-9 µm, with a basal clamp. Basidiospores broadly ellipsoid or ovoid to subglobose, slightly thick-walled, smooth, hyaline. negative in Melzer’s reagent, 4.5-6 × 4-5 µm.

Type of rot. Causes a white rot in dead hardwoods.

Cultural characteristics. Unknown.

Sexuality. Unknown.

Substrata. On dead hardwoods, often from buried wood or roots. Known from Fagus, Fraxinus, Carpinus and Alnus in Europe.

Distribution. A rare species, known from France, southwest Germany, Czechoslovakia, Yugoslavia, Byelorussia and Georgia. See Jahn (1973:82) and Kotlaba & Pouzar op. cit. for references on the European distribution. Widespread in North America.

emphasis added.

Spore images
By: Christine Braaten (wintersbefore)
2012-06-20 13:07:32 AEST (+1000)

I will upload spore images tomorrow, but the inamyloidicity was unambiguous- no amyloid reaction. This keys out to Microporellus in NA Polypores because it is: stipitate, color of pore surface is white, hymeniphore is poroid, rot type is white, spores are smooth, thin walled, not pigmented, not amyloid/not dextrinoid, clamps present. Now, it says that it must also be “monomitic,” and I will have to confirm that because I’m not sure what that looks like under the microscope.

you say
By: Danny Newman (myxomop)
2012-06-20 12:52:54 AEST (+1000)

you saw inamyloid spores. can we have a look?

By: Christine Braaten (wintersbefore)
2012-06-20 12:42:26 AEST (+1000)

is the closest I could come to using North American Polypores (no species listed in there for Tyromyces were stipitate).

North American Polypores
By: Christine Braaten (wintersbefore)
2012-06-20 12:23:40 AEST (+1000)

I tried for an hour today to key this out in there, and any assistance with that would be most helpful. In my description of consistency, this was “spongey” but not “soft,” in that it held enough water so that when squeezed it could actually be “wrung out.” But still too tough that it could not be torn apart with your fingers.

By: Danny Newman (myxomop)
2012-06-20 12:14:44 AEST (+1000)

your consistency description has me a bit confused. I think of “spongy” and “very tough, even to cut with a knife would be difficult” as mutually exclusive. The Tyromyces I’ve handled (which isn’t many) were some combination of watery, spongy, soft, pliable, and most definitely sectionable, though less so upon drying. It sounds like this is more conky/coriaceious with some give in the tissues, but not “spongy” per se. Am I right?

Consistency aside, the inamyloidity and abundant clamps in your micrographs match up well with Tyromyces, and probably a boat load of other polypores as well. If you have access to highfalutin mycology texts, try and take this through Gilbertson & Ryvarden’s North American Polypores Volumes I & II.

By the way, are those purple stains in the second to last macro photo?

By: Christine Braaten (wintersbefore)
2012-06-20 12:07:10 AEST (+1000)


Stipe minutely velvety.

By: Christine Braaten (wintersbefore)
2012-06-19 21:52:14 AEST (+1000)

Spongey but very tough, even to cut with a knife would be difficult. Very watery and sponge-like. No distinct odor like I’ve seen with some other Tyromyces.

can you describe the texture/consistency?
By: Danny Newman (myxomop)
2012-06-19 15:59:08 AEST (+1000)

Created: 2012-06-19 12:44:58 AEST (+1000)
Last modified: 2012-06-20 13:17:00 AEST (+1000)
Viewed: 391 times, last viewed: 2018-03-17 08:10:10 AEDT (+1100)
Show Log