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The following passage is vague, but troubling. It is from A Sierra Nevada Flora by Dr. Norman Weeden, Professor of Plant Genetics at Montana State University.

"The reader may be aware that even in common crops such as squash (Cucurbita pepo) or potato (Solanum tuberosum) genetic or environmental variation can make the crop extremely toxic. In much the same way, selenium accumulators such as locoweed (Astragalus spp) can be poisonous on some soils and relatively innocuous on other soils. Although the author is not aware of specific instances where the toxicity of a Sierran species has been demonstrated to vary as a result of genetic differences, such variation certainly exists."

Is anyone aware of an example of an edible plant being toxic when found growing in a different soil?

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This is a great question.

I can not speak specifically about the soils and their toxicities in the Sierra Nevedas of California. My experience there is limited, though I am familiar with locoweed. Soil toxicity overall is a topic I am not very knowledgeable about.

Generally speaking when we are considering concerns about eating edible plants for our classes, we consider things like:

- Proximity to roads

- Proximity to mining activity

- Proximity to other industrial activity

- Proximity to other sources of pollution

- Proximity to industrial farms or other areas likely sprayed with pesticide or herbicide

So, we don't gather edible plants near road ways, in industrial areas or in places that show signs of mining activity. We never really consider selenium toxicity other than in those plants that are known to be toxic such as locoweed and others. Here is an excerpt from a scientific paper on selenium and its effects on plants that might give you some insight, and perhaps, ease your mind regarding concerns on its toxicity:

" Plants vary considerably in their physiological response to selenium (Se). Some plant species growing on seleniferous soils are Se tolerant and accumulate very high concentrations of Se (Se accumulators), but most plants are Se nonaccumulators and are Se-sensitive. "


N. Terry, A. M. Zayed, M. P. de Souza, and A. S. Tarun
Department of Plant and Microbial Biology, University of California Berkeley, Berkeley,

Here is where I found the article:

I can understand after reading that statement that you have concerns about selenium. My understanding is plants that accumulate selenium often use it as a defense against herbivores. Locoweed is known in many parts of the west, and in many field guides for plants of this region, as a toxic plant to be avoided. I can not speak much regarding squashes, but I know that the upper (above ground portions) and to some extent the raw tubers of potatoes are some what toxic. It is quite possible that potatoes use selenium in a similar fashion.

Bob, I noticed your focus has been on plants of the Sierras. Are you spending a lot of time down there right now?
Because I live in the Sacramento Area most of my backpacking is in the Sierras and Lassen National Park. Lassen, by the way, is in the part of the Cascades that lie in California. Because I backpack in the Sierras, it's good for me to study the plants in that area.

My favorite backpacking area, however, is in far northern California in the Marble Mountain Wilderness. I don't go there as often as I'd like because it's hard to get people from here to go that far. I mention it because that part of the state is really part of the Pacific Northwest. So the environment in the Marble Mountain Wilderness, or at least parts of it, is very similar to the lush jungle-like environment of Alderleaf College.
The Sierras are an amazing locale. I love that part of the country. I use to make trips out there when I was younger and lived in California. I was especially fond of the Lake Tahoe area and Sequoia-Kings Canyon area. My heart just about skips a beat when I think about the Sierras, and yet, I also feel that way about where I live now. : )

I am familiar with Mt. Lassen, at least from a distance of seeing it from I-5. I always wanted to visited that area. Some day soon I will have to go.

The Marble Mountain Wilderness area sounds wonderful. Again, my main experience with northern CA is just driving through. But, I have always wanted to visit more of it on foot. Do you keep a blog of your hikes and adventures? It might be fun to see your photos of these areas and read about your experiences.

There are some really good books on the natural areas of California. I bet you probably already have some, but I will still recommend a few:

AUDUBON FIELD GUIDE TO CALIFORNIA is a great little pocket field guide. We have one for the PNW that we use for Alderleaf students. I have taken to putting check marks or stars next to the photos of edible plants. This way if all I have is the field guide, I still know which ones I can eat.

Though, obviously if you want to get to know your plants/animals/fungi/etc. in more detail, you will need a more informative guide.

A NATURAL HISTORY OF CALIFORNIA by Allan A. Schoener is an excellent overall resource of CA. That was an important resource for me when I getting more involved in learning about the natural wonders of CA. It does cover the entire state, but the information in there is very good.

SIERRA NEVADA NATURAL HISTORY by Tracy I. Storer, Robert L. Usinger and David Lukas is a great resource that is more specific to the Sierras.

And if you are looking for more info on soils and plants, check out AN INTRODUCTION TO CALIFORNIA SOILS AND PLANTS: SERPENTINE, VERNAL POOLS AND OTHER GEOBOTANICAL WONDERS by Arthur R. Kruckeberg. Many other books in this series of "California Natural History Guides" are an excellent resource. I would recommend you look into them further.

Lastly, I would recommend in the Peterson's Series A FIELD GUIDE TO CALIFORNIA AND PACIFIC NORTHWEST FORESTS by John C. Kricher. We use an expanded version of this book in our classroom.

If you want to use me or Jason as a resource to help you identify plants, animals or fungi, please do so! Take lots of photos and share them. Photos are invaluable in helping identify mysteries because sometimes our memories or description are not complete or accurate.

Looking forward to lots more from you, Bob.
Thank for the recommended reading Filip. I am especially interested in the last book.

I was also interested to see Tracy Storer's name. He co-authored a fascinating book, California Grizzly
which is a history of encounters between people and grizzly bears during the Indian era, the Spanish era, and the American era in California.

Unfortunately you may not be hearing much from me in the next year. I was signed up for the edible plants class I posted about earlier. But my wife broke her arm hiking in Utah this week, and so I've had to back out of the class so that I can take care of things at home. But I will try do to the class next year.

At the very least this may give me an extra year of life. After failing to make fire, and failing to build a snare, last March at Alderleaf, I figured I'd likely poison myself in the edible plants class. But I'll be back sometime.
It is interesting to ponder that if some plants are tolerant to unusual properties in a particular soil, than perhaps with time a skilled naturalist would be able to understand some information about the soil without using reagents for testing. Would plants ever be used as indicator species to find mineral deposits, or in soil identification? It's a bit similar to the idea of up, down, all around in relation to nitrogen, phosphorus and potassium content in soil.


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