Observation 137454: Lactarius occidentalis A.H. Sm.

When: 2013-06-23

Collection location: Sunset Rest Area, Highway 26, Clatsop Co., Oregon, USA [Click for map]

Who: Sava Krstic (sava)

No specimen available

In a mixed forest.

Milk white, unchanging. Taste mild.

Spores white, 9 × 7 microns.


Sphaerocysts from cap trama, ~50 microns.

Proposed Names

28% (1)
Recognized by sight
28% (1)
Recognized by sight: yellow striate cap, delicate, white latex.
Used references: Milk Mushrooms of North America.
27% (1)
Recognized by sight: striation at least half the radius of the cap, taste mild. Sp 7-9.5 × 5.5-8 μm
Used references: Funga Nordica (Syn: L. cyathula ss Lange)
60% (2)
Recognized by sight: Although a little more sulcate then what I’m use to, it’s worth comparing to Hesler & Smith’s description.

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Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
By: Sava Krstic (sava)
2013-12-31 20:26:11 CET (+0100)

Thank you, Debbie.

Andy Methven…
By: Debbie Viess (amanitarita)
2013-12-31 16:30:09 CET (+0100)

concurred with the ID of occidentalis in recent correspondence with me.

By: Sava Krstic (sava)
2013-06-26 08:24:21 CEST (+0200)

Added photos of spores mounted in MLZ. Amyloid ornamentation seems to fit the description of L. occidentalis: “reticulum of [presumably amyloid] warts and spines connected by amyloid lines forming nodulose [bumpy] ridges”. Basidia ~45 × 10 (without sterigmata, which are up to 7 microns long). Unfortunately, I was unable to see any cheilocystidia or pleuromacrocystidia.

Debbie, Irene, Noah
By: Sava Krstic (sava)
2013-06-25 07:19:28 CEST (+0200)

Thank you for your ID efforts.

The milk wasn’t that scant in one of the mushrooms. When I poked the cap twice with a needle, drops of white milk about 1 mm large showed immediately. They remained white for a few minutes while I was watching. And they dried white too. I just added a photo which shows what these two drops look now. I added another picture that shows white spots which I would interpret as dried latex. These spots can be seen in many places where the mushroom was broken.

Unfortunately, I cannot get any latex out now and perform the test on white paper.

Will try to do more and better microscopy tomorrow.

It’s tough
By: Noah Siegel (Noah)
2013-06-24 23:33:52 CEST (+0200)

to get latex from L. occidentalis, and chances are you would only notice the yellowing if you put it on white paper.

And although Hesler and Smith don’t mention the sulcate (striate) cap, one of Smith’s pictures show it.

spore size within the range of occidentalis…
By: Debbie Viess (amanitarita)
2013-06-24 23:26:37 CEST (+0200)

but what about the unchanging white latex? occidentalis’ white latex should turn yellow, or at least stain paper yellow (according to Smith).

By: Irene Andersson (irenea)
2013-06-24 20:26:58 CEST (+0200)

If you use Melzer’s on the spores, you should get a much better picture of the ornamentation – could be important details there.

yeah, the spores are off…
By: Debbie Viess (amanitarita)
2013-06-24 18:48:22 CEST (+0200)

latex is described as “slightly acrid,” which sounds as though it could be missed.

the description of obscuratus also does not really match the photo in the Bessette book, either, but the photo of obscuratus on page 99 does look an awful lot like your little mushroom. there are not many with that striate cap.

closest I could come with the materials at hand.

close, but no cigar! ;)

Maybe obscuratus
By: Sava Krstic (sava)
2013-06-24 18:18:48 CEST (+0200)

Thanks, Debbie. The match with L. obscuratus is not perfect: “Spores 7-7.7+ x 5.7-6+ μm”, “taste peppery”.

Lactarius obscuratus…
By: Debbie Viess (amanitarita)
2013-06-24 18:06:43 CEST (+0200)

or at least our American version of it, has been recorded from the PNW.

nifty Lactarius, Sava.
By: Debbie Viess (amanitarita)
2013-06-24 17:58:27 CEST (+0200)
Yes, alder
By: Sava Krstic (sava)
2013-06-24 17:44:34 CEST (+0200)

… but also maple and Douglas fir in the vicinity.

Forgot to mention: caps are not viscid.


under Alder?
By: Noah Siegel (Noah)
2013-06-24 13:12:23 CEST (+0200)

Created: 2013-06-24 08:13:05 CEST (+0200)
Last modified: 2013-12-31 16:28:57 CET (+0100)
Viewed: 158 times, last viewed: 2018-03-11 22:58:56 CET (+0100)
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