Observation 212085: Hysterangium separabile Zeller
When: 2015-08-05
( 5000m)

Notes: Found beneath young saplings of Douglas fir, Western hemlock and Western red cedar(all within five feet of Hypogeus sample).

Elevation: 5000ft.

Temp: low 70’s.

Note: Was going to try and slice this down the middle to show inner context(as I usually do with truffles and false truffles), but the damn thing was rock solid from drought. I have kept the specimen, vouchered, bagged and will study further.

Bone white, slight pinkish brown discoloration on lower portions of gleba. Small evident pigtail stem in center of sporophore-perhaps rhizopogon? Will delve further once I can crack the thing open.

Species Lists


Next to mushroom knife for scale.
Note brownish yellow, pink hue on right side.
Stem arranged vertically. Approximately 3 inches beneath the soil.
Where I came upon the find. Squirrel holes everywhere surrounding. Beneath soil this seems to be a rhizomatous hub for young saplings.
Where I came upon the find. Squirrel holes everywhere surrounding. Beneath soil this seems to be a rhizomatous hub for young saplings.

Proposed Names

28% (1)
Recognized by sight
-10% (2)
Recognized by sight: Very solid, even when immature and in humid conditions.
Used references: Field Guide to North American Truffles
56% (1)
Recognized by sight: Single rhizomorphic attachment reminds of H. coriaceum
Used references: Field Guide to North American Truffles
84% (1)
Recognized by sight: According to Field Guide, peridium quickly bruises pink to red to rosy-brown. The peridium also breaks away quickly from the gleba.
Used references: Field Guide to North American Truffles

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

Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
Thanks again Daniel!
By: Drew Henderson (Hendre17)
2015-08-07 19:20:12 PDT (-0700)

Thank you for taking the time to key this out and give such thorough feedback. I greatly appreciate your help, along with all the other species you’ve led me to to over the last few years(not giving the species away easily and hinting towards the right keys), made me learn and study keys more thoroughly. You are a wise educator kind sir.

Good luck this season!


Another feature
By: Daniel B. Wheeler (Tuberale)
2015-08-07 11:09:52 PDT (-0700)

of H. separabile is a dendroid columella: a branching sterile stipe-like structure, which in this species should be transluscent. The base of said dendroid columella should continue into the base. Really only need to look at the base carefully: I don’t recall any native species with this feature other than the suggested species. The base should much easier to disect. The outer shell will tend to fracture readily, like the peridium.

By: Drew Henderson (Hendre17)
2015-08-06 15:50:20 PDT (-0700)

Hysteriangium will be where I start… I am hoping I didn’t collect one that is too far gone to slice. As you mentioned some disintegrate. Thank you for all your vast knowledge and propagation experience with our hypogeous friends. I am still hesitant to dig any deeper than 5 inches into the rhizomatious networks beneath the surface. I am greatly becoming more and more interested in the underground and hopefully can get more specimens as I learn new methods.

You are an asset. Thank you again sir!

Spores truly,


Not Hymenogaster
By: Daniel B. Wheeler (Tuberale)
2015-08-06 15:18:10 PDT (-0700)

but Hysterangium, Drew. I tried to delete Hymenogaster, but MO wouldn’t let me.

The interior of Hymenogaster will be gelatinous-tough, with the consistency of a superball. The interior gleba may appear to be filled with gel-filled spaces. Sometimes (some Hymenogaster species) may even have locules present.

Spore-filled gleba may be green or bluish. When completely mature, the sporocarp turns softer and may shatter in your hands. The peridium is usually white, but may quickly stain another color. Best to keep a photograph of the recently-unearthed fungus, and another of the handled sporocarp, as staining/bruising can be an important feature for the group. Not all sporocarps may have the mycelial cord attachment: often breaks off during excavation.

By: Daniel B. Wheeler (Tuberale)
2015-08-06 15:05:34 PDT (-0700)

often develop well-colonized areas, which tend to hold soil together, even on very steep slopes. The sporocarps develop within this tenacious, tough, sometimes fibrous and difficult to tear-apart mycelial mat. Mat communities often develop in steeper slopes. Younger specimens can be found at depth, usually nearby. It is often necessary to literally tear apart the mat communities, at least some, to reach the underlying sporocarps, which can be completely surrounded by the mycelial mat. While you observe one specimen at the soil surface, there can be literally hundreds or thousands of sporocarps nearby and underground. I have found these communities up to 14 inches deep (I wasn’t willing to go deeper) associated with Garry’s oak (Oregon White oak) on Peterson’s Butte. I have also found several hundred surface sporocarps of Hysterangium associated with Noble fir in a Christmas tree plantation near Oregon City.

Hysterangium often has a texture (normal) of a superball, and reacts like one when bounced on the floor.

Hey Daniel!
By: Drew Henderson (Hendre17)
2015-08-06 15:04:48 PDT (-0700)

Long time no post my friend. I forgot to include the odor with this one… My wife and I immediately thought of sharp parmesan or toe jam(grossly enough-LOL).

Could be similar to the briny, acrid odors in black or calumet olives I s’pose.

I have an old key from Trappe that I will try to work through this weekend and maybe we can get to the bottom of this. Hopefully, I don’t cut my hand off doing it!

Glad to be back in touch-

Hope you are well and am looking forward to a possible truffle hunt with you in the future. Trade you a few Agarikon spots for Hypogeus/Xmas tree farm spots this year???

Either way,

I hope you are well and would love to get you up to the mountain Passes for a foray this season with you. What should I exactly be looking for in the interior from your experience with these hard Hymenogasters?

Was there an odor?
By: Daniel B. Wheeler (Tuberale)
2015-08-06 14:51:44 PDT (-0700)

When mature (mushy), Hymenogasters often develop an odor similar to over-ripe olives.

Of the possible hosts,
By: Daniel B. Wheeler (Tuberale)
2015-08-06 14:50:31 PDT (-0700)

Western Red cedar is never mycorrhizal. Douglas fir and Western hemlock both widely mycorrhizal. Likely something like Hymenogaster coriaceum, but at 5,000 feet elevation not terrible likely. Would have liked to see the interior, although sectioning the sporocarp will take a steady hand and considerable force, even with a surgical scalpel.

Created: 2015-08-06 11:28:38 PDT (-0700)
Last modified: 2015-08-06 22:09:11 PDT (-0700)
Viewed: 68 times, last viewed: 2016-10-22 21:38:45 PDT (-0700)
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