This post focuses on how to identify a plant's species once you have some idea which family or genus it belongs to. On my walk yesterday, I found two plants that were new to me. Here's how I identified each.
(As always, if you're new to foraging and want to give it a try, please read the first diary in the series as well as the linked diary for the full discussion of each plant. For a complete list of all plants covered in the series, click here.)
I found this first unknown plant under a juneberry bush (Amelanchier canadensis). Even from across a field, I suspected it was a mustard, but previous visits to that field made me think it was probably winter cress (Barbarea vulgaris, covered here). But one look at the fern-like leaves convinced me I'd found a new mustard.
The mustard family (Brassicaceae) is identified by having 4 petaled flowers (mostly yellow, but sometimes white or pink) in terminal clusters, many lobed leaves and slender seedpods. The flowers and seeds usually co-exist on the plant at the same time. Although there's a certain amount of variation in the family, if you spot tall and slender spikes of yellow, 4 petaled flowers in a field or along the edge of a road, you've almost certainly found a mustard. To be certain, look for 4 sepals and 6 stamens (2 short and 4 long-- you may need a magnifying glass) and leaves that smell like cabbage.
Having confirmed it was a mustard, I had a few options for getting a more specific ID. I could look at the entry in Wikipedia for Brassicaceae, but Wikipedia is missing lots of species and often doesn't have photos for less common plants. The USDA plants database entry has more photos as well as maps showing geographical ranges, but there's still too many genera (each containing many species) to wade through.
Luckily, I carry the Peterson Field Guide Wildflowers: Northeastern/North-Central North America on my walks. Although the book is divided by flower color and then flower characteristics, I already knew the family, so I could narrow it down even further. The beginning of the book has a listing of plant families and the pages that the flowers of those families are listed on, so it was easy to learn that yellow mustard flowers are on pages 158-160.
From there, I simply looked at the plant drawings until I found one with fern-like leaves. My unknown plant is tumble mustard (Sisymbrium altissimum). I gave it a taste, and it tastes quite similar to winter cress.
Despite having white flowers instead of yellow, I again knew this plant was a mustard as soon as I saw it. Shepherd's purse (Capsella bursa-pastoris) and poor man's pepper (Lepidium virginicum, both covered here) have quite similar looking flowers but the former has triangular seed pods, and the latter's seed pods are quite a bit smaller and more oblong than those of my mystery plant. Nonetheless, knowing those other two plants gives me a very big clue that my unknown plant is not only a mustard but also a peppergrass.
This time my Peterson guide let me know that white mustard flowers appear on pages 82-86. Bingo! There it was on page 82: field pennycress (Thlaspi arvense). It doesn't have as much of a peppery bite as poor man's pepper, but it's not completely mild, either. Next time I see it, I'll gather some to experiment with how to cook it.
I hope this post gives you a little more insight into how a plant goes from unknown to identified. If you want to learn more about how to identify the family of just about any plant you see, I highly recommend Botany in a Day by Thomas J. Elpel. See you in two weeks!
Helpful foraging resources
If you'd like to learn more about foraging but missed the earlier diaries in the series, you can click here for the previous 51 installments, and here for RonV's 4 part mini-series on medicinal plants and how to use them. As always, please feel free to post photos in the comments and I'll do my best to help identify what you've found. (And if you find any errors, let me know.)
"Wildman" Steve Brill's site covers many edibles and includes nice drawings.
"Green" Deane Jordan's site is quite comprehensive and has color photos and stories about many plants.
Green Deane's foraging how-to clips on youtube each cover a single plant in reassuring detail.
Linda Runyon's site features only a few plants but has great deals on her dvd, wild cards and books (check out the package deals in particular).
Steve Brill's book, Identifying and Harvesting Edible and Medicinal Plants in Wild (and Not So Wild) Places is my primary foraging guide. (Read reviews here, but if you're feeling generous, please buy from Steve's website.)
Linda Runyon's book The Essential Wild Food Survival Guide contains especially detailed information about nutritional content and how to store and preserve wild foods.
Samuel Thayer’s book The Forager's Harvest is perhaps the finest resource out there for the 32 plants covered. The color photos and detailed harvest and preparation information are top-notch. His second book, Nature's Garden, is just as good. For an autographed copy of either book, order from Sam's website.
Steve Brill also offers guided foraging tours in NYC-area parks. Details and contact info are on his website.
Don Wiss’s website is a treasure trove featuring hundreds of photos of common northeastern edibles.
For well-sourced info on the medicinal uses of plants, Plants for a Future is a site I turn to time and time again.
Finally, the USDA plants database is a great place to look up info on all sorts of plants.