Observation 47186: Rhizopogon Fr. & Nordholm
When: 2010-06-19
Collection location: Sintra, Portugal [Click for map]
Who: zaca
No herbarium specimen

Notes: This observation is related with that of MO#46788. This time I was looking for a younger specimen. I was able to find only one. The color of the gleba of this specimen was like the color of sand, in contrast with the blackish of the specimens in the first observation.

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No problem, Tuberale,
By: zaca
2010-06-21 15:28:29 CDT (-0400)

I feel that you only want to help me and thus no offense is possible. Your comments are very welcome.

I apologize if I offended.
By: Daniel B. Wheeler (Tuberale)
2010-06-20 18:02:10 CDT (-0400)

I was merely trying to establish how close to the original collection this was uncovered. Assuming this was the only other sporocarp unearthed in the immediate area, it would be logical to assume it is the same species, but less mature.

While some Rhizopogon do mature extremely fast, others species may take weeks or perhaps even over a month to reach maturity.

I regret not having any experience in Portugal.

Mailing a dried sporocarp to Matt Trappe in care of NATS is probably the best method of determining species that I know of. They have developed keys I’m still trying to learn how to read.

The really neat thing about Rhizopogons is that they are relatively easy to grow. A single mature (or even immature) sporocarp will have enough spores to be crushed into powder and added to a sprayer. A 1-second spray of this spore slurry should provide 10,000 to 100,000 spores. It takes only about 10,000 spores to inoculate a new tree. I prefer to over-inoculate. A 2-second spray takes marginally longer for inoculation, and provides much greater colonization likelihood. It has been suggested a single averaged-sized Rhizopogon contains enough spores to inoculate at least a square mile of seedling trees at 10,000 spores/seedling. There is strong correlation, at least here in Oregon, that trees which have been inoculated with Rhizopogon provide the pre-requisites for Tuber colonization later in the tree’s life. Rhizopogon is one of 7 indicator species that I must find before I attempt to inoculate Tuber in a new stand.

I apologize if I misread your first comment.
By: zaca
2010-06-20 17:46:38 CDT (-0400)

It seemed to me that you had not read the notes, because there I established the connection between the two observations. The site where I tried was exactly the same of the previous observation. The specimen I found was about 20 cm from the others. For his appearance I assumed that it was of the same species: only the color was slightly lighter, being younger, everything else was similar, including the rizomorphs. I was also able to confirm that the nearest tree was about 5 meters away and that all the surrounding trees were pines.
Thank you for all information and reports of past experiences with this type of fungi.

I did read the notes.
By: Daniel B. Wheeler (Tuberale)
2010-06-20 14:18:34 CDT (-0400)

I don’t understand your reference to “related” to MO #46788. Was this observation found near where #46788 was observed? How close? One meter? 15 meters?

One method of finding hypogeous fungi is to look for fungal pits where animals have found something underground, dug a small pit to reach it, and (perhaps) left a portion still there or nearby.

But I have found pounds of Rhizopogons in a day. Rarely are they all the same species, even though they may fruit next to each other. The spores of Rhizopogon are notoriously difficult to distinquish from similar Rhizopogons even though several may be fruiting in the same square meter on the same day.

Most Rhizopogon researchers are relying on mycorrhizal associations to attempt distinquishing one collection from another. Rhizopogons may fruit at considerable distance from their host plant and are very sensitive to available moisture. So it is quite possible to have multiple species fruiting in the same square meter or even 5 square meter area, if it is in a depression that captured more water than the surrounding area.

I’m reminded of one of the more interesting collections of Rhizopogon I have found: Rhizopogon ater. I happened to have a small pocket microscope with me at the time, and examined the gleba through the microscope (100x). The gleba showed what appeared to be silver threads meandering through the gleba, as if they were woven through the gleba like a cloth fabric. This rather distinctive feature (I have not seen it on any other species) became an important identifying characteristic.

Scientists are still not certain what characteristics are key to identification of Rhizopogon species, which is what makes them so difficult.

Thanks, Tuberale, for the comments,
By: zaca
2010-06-20 13:11:33 CDT (-0400)

but you forgot to read the “Notes” included in the observation.

Rhizopogon fruitings
By: Daniel B. Wheeler (Tuberale)
2010-06-20 12:37:14 CDT (-0400)

can occur at any time. Some species develop from primordia to full maturity in less than 2 weeks. Several species are now confirmed to have fruited year-round.

This observation looks very similar to MO #406788 to my eye. It would be a perfect specimen for slicing and drying for later study. One of the factors which MAY assist identification is the size of the locules in the gleba. Rhizopogon are genetically related to Suillus and Boletus mushrooms. The locules are cross-sections of the convoluted tubes remaining from from the original mushroom. Sometimes the shape of the locules can be informative as well: some are quite angular, almost like square pipes than tubes; in others very longated tubes; in still others, tiny and uniformly roundish tubes.

Any initial bruising or color changes, especially just after the gleba is sliced, is important. Many Rhizopogons bruise or stain on or near the peridium.

On this specimen I saw nothing very distinct for color changes or bruising, nor anything distinctive about the locules. But it could be important for future collections.

Created: 2010-06-20 12:16:53 CDT (-0400)
Last modified: 2010-06-20 12:28:48 CDT (-0400)
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