Observation 93418: Tuber californicum Harkness
When: 2012-04-27
Herbarium specimen reported

Proposed Names

21% (2)
Used references: Tuffles of NA, Trappe
Based on microscopic features: globose “soccerball” spores

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Eye3 = Observer’s choice
Eyes3 = Current consensus

Comments

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Only one way to know with certainty.
By: Daniel B. Wheeler (Tuberale)
2012-09-17 12:30:15 PDT (-0700)

Need to see microscopy.

I have looked at the second photo more thoroughly. Under a magnifying glass, the second photo shows just as many brown spores as black. The peridium is reddish-brown to orange-brown. Tuber californicum peridium should be chocolate-gray to black.

The photo included in Field Guide to North American Truffles is in my opinion rather immature. The spores are not at all black, as would be in mature specimens. A better photo is available at the NATS website.

A final point: Tuber californicum is rarely, if ever, over 1 inch in diameter. Usually is is nearly globose, but the Field Guide photo mentioned above is more ovate-globose. The overall shape of this obs. appears irregular, another point for immaturity. Many Tuber species have irregular shapes when immature, but tend to plump-up with maturity.

been pondering this one still
By: Daniel Nicholson (danmadrone)
2012-09-17 10:37:21 PDT (-0700)

A little follow up as I have a moment finally, later drier specimen pulled from the window sill after being in the refer for months looks as if spores did darken. I think it is a more than half decent fit for T. californicum.

Not mature T. californicum
By: Daniel B. Wheeler (Tuberale)
2012-05-14 15:36:25 PDT (-0700)

and very immature. Mature T. californicum has black spores, and near maturity the entire gleba turns cafe au lait with white sterile veins. Under 30x the spores are black. The peridium is dark reddish-brown. This obs. has no reddish-brown peridium.

NATS has collections from all over the US and Canada. The late Dr. Helen Gilkey did most of her early collecting in California, before she published “A Revision of the Tuberales (truffle fungi) in California” in 1916. In 1939 she published “The Tuberales of North America”. Dr. Gilkey was my botany professor at Oregon State University before dying 1 August 1972.

Near mature T. californicum specimens can be found at: http://www.natruffling.org/photo.htm. The specimen on the far right is approaching maturity, but IMO still only 80% mature. It can be nearly black at maturity.

NATS has collections of T. californicum from every month of the year.

Perhaps you are correct in saying this obs. is not T. shearii. It certainly is not T. californicum.

That leaves us with a possible species novum.

Without much more detailed information, probably requiring a scanning electron microscope and spore details, we may never know.

I will defend my tentative identification of T. shearii, which I have found mature with Douglas-fir in May and June from Oregon, and have voucher collections which have been added to the NATS database and OSU Herbarium.

You state “I doubt NATS has any observation from my area…”. Dr. Gilkey collected extensively in California. Her collections were left to the OSU Herbarium collection at her death in 1972.

dont agree w/ T. shearii
By: Daniel Nicholson (danmadrone)
2012-05-14 07:48:06 PDT (-0700)

I doubt NATS has any observation from my area and we are usually bone dry in two months, this fungi is close to maturity in my opinion. Looking into T. shearii I see a very dark truffle that doesnt resemble my collection very well in my opinion.

To Daniel:
By: Daniel B. Wheeler (Tuberale)
2012-05-01 11:57:29 PDT (-0700)

“sourish stinky smell” may be from the ethylene, which is a chemical given off from Tubers to hasten maturity. The sporocarp is trying desperately to produce some mature spores to ensure it’s ability to disperse by an animal. The ethylene odor is variously interpreted by different noses. But for certain it should be much stronger and kind of “chemical” than the original odor. Ethylene sometimes makes my eyes water, if that helps any. Ethylene is also the chemical produced by many fruits and vegetables during the maturation process: bananas, apples, and tomatoes all produce it. So when these fruits and vegetables are placed inside a brown paper bag, it tends to concentrate the ethylene and helps to mature them.

Pubescence present.
By: Daniel B. Wheeler (Tuberale)
2012-05-01 11:50:39 PDT (-0700)

Visible in the photos if you blow them up. I think Debbie has a very good handle on what it may be.

But I respectfully disagree.

I think this may be a better match for T. shearii. The reason is kind of simple: T. californicum in my experience has a nearly black peridium. At maturity, the spores and gleba will be chocolate-brown to black coffee. T. californicum probably would not be mature for another 2-3 months in your area, based on collections submitted to NATS to date.

In my area, T. shearii is by far the rarer variety, but this seems to match closely. Pinus is actually a favorite host species for many Tuber species. Globose reticulatum seems limiting too. But T. shearii is more brown and finely pubescent. My collections of T. shearii at Jones Creek Tree Farm were typically found with Douglas-fir, but Douglas-fir is actually close to both Pinus and Tsuga (Pseudotsuga), so host tree in this case not conclusive, although compelling.

Pubescens should be visible within the venae externae if the photos are blown up: it is a fine fuzz, and if often overlooked even by the so-called experts. (I’ve beem called that name before. Yuk!)

Even for T. shearii, this is immature. I would like to see a collection, probably from the same tree, in June or July if that’s available, Daniel. If the gleba (interior) is mostly black at that time, it is likely T. californicum. If the gleba is more sepia or cafe au lait, probably T. shearii. At this stage of development I can’t be certain.

I’d imagine that just handling would destroy that delicate feature…
By: Debbie Viess (amanitarita)
2012-05-01 10:47:25 PDT (-0700)

I agree that this is a best match for californicum, with the info that we have at hand.

no hyphal pubescence
By: Daniel Nicholson (danmadrone)
2012-05-01 10:22:34 PDT (-0700)

a kind of hard thing to look for, but under scope nor handlens was “hyphal pubescence” observed. Somehow I think this doesnt remove T. californicum from a possibility. Sourish stinky smell from maturing specimen after an original sweet garlicky smell when youger and fresher was also obs.

globose reticulate (soccerball!) spores…
By: Debbie Viess (amanitarita)
2012-05-01 09:58:32 PDT (-0700)

only match T. californicum and T. shearii in the Trappe Truffle Guide (although I suppose there could be more options that were simply not included).

T. shearii has a thicker peridium than californicum; californicum is the better match here.

The other distinguishing character for californicum is “a fine pubescence of long tapered hyphal tips.” Could you see these with your hands lens, Daniel?

T. californicum does not appear to be restricted in its host trees, though, occurring w/Doug Fir, pine, oak and hazel.

Associated with Pinus ponderosa
By: Daniel Nicholson (danmadrone)
2012-05-01 09:26:11 PDT (-0700)

Hi I believe it to be Tuber californicum by some indications from Trappe’s book. It is almost definitively growing with Pinus ponderosa.

Many Tubers are found with specific tree species, and some shrubs.
By: Daniel B. Wheeler (Tuberale)
2012-04-30 16:10:05 PDT (-0700)

Do you know what trees and shrubs were nearby?

Created: 2012-04-27 10:24:00 PDT (-0700)
Last modified: 2012-09-17 10:30:35 PDT (-0700)
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