Notes on Plant ID

I had an email this morning from someone whose plant ID app was telling her that plants she had bought from me as Anise-hyssop were Stinging Nettle or possible Catnip. Now, I have never used a plant ID app but, for plants whose most easily distinguishing features are non-visual — familiar scents for Anise-hyssop and Catnip, and irritating stinging sensation for Stinging Nettle — using a purely visual method of IDing seems inadequate. Although I haven’t used an app, I see many posts and comments from people who encounter errors in their app’s IDs.

So, what do I recommend for IDing plants? Honestly, I think the best place to start is good ol’ Peterson’s Field Guide. Yes, it has errors and, yes, it hasn’t been updated since it was first published a zillion years ago, but for the beginner, it is easy to use and it covers many of the basics. When I started growing Prairie Blazing Star (Liatris pycnostachya) I realized I would need to be able to tell it apart from Spike Blazing Star (L. spicata). I knew Prairie was taller and a bit later in bloom than Spike, but when one is growing them in pots, that’s not very helpful. I thought I would need to sit down with some pretty heavy-duty dichotomous keys and actually do some botany. But, hey, both are in Peterson’s and Prairie Blazing Star’s field mark was clearly indicated by an arrow on its line drawing. Excellent!

For less common species and more up-to-date botany, I look on-line for resources such as the University of Michigan Herbarium. I found a dichotomous key there when I was puzzling over the differences between Long-leaved Bluets and Canada Bluets. However, even though I knew exactly where on the Bruce Peninsula I had collected the seed of what I thought was Canada Bluets, I am still puzzled, because published authorities do not agree on the ranges for the two. Oh, well, they are both very pretty.

That’s the thing with keys, They are only definitive for the geographic range they are intended for. Still, you can often get good descriptive information when you get down to species using a key. Lets’s take a Goldenrod I have recently started carrying as an example.

Last year, Berit Erikson of the Corner Pollinator Garden, gave me some seedlings of something she called Ontario Goldenrod (Solidago ontarioensis), which is now on my list. Let’s see if Berit and I were right about its name.

I know that Ontario Goldenrod is considered Rare in Ontario, so the first place I am going to look is a booklet called “The Asters, Goldenrods and Fleabanes of Grey and Bruce Counties” published by the Owen Sound Field Naturalists. Yes, Ontario Goldenrod is one of the species described in this book. Because I already think I know what my plant is, I am going to skip the dichotomous key and go straight to the description.

The first thing I notice is that this booklet, published some years ago, calls the plant Solidago simplex var. ontarioensis. Is that the correct botanical name for Ontario Goldenrod? A quick check of VASCAN (Database of Vascular Plants of Canada) and I learn that the currently accepted botanical name IS Solidago ontarioenis. Yay, Berit. (Technically, it is Solidago ontarioensis (G.S. Ringius) Semple & Peirson, but let’s not get into that today.) The Flora of North America website says that Solidago simplex, or Sticky Goldenrod, splits into seven varieties. Likewise, the Grey-Bruce booklet says “Solidago simplex splits into a number of varieties with specific geographic distribution.” This underlines the importance of knowing where your seed came from. If I really needed to know exactly what I have got, I would have to quiz Berit more closely than I did on the origin of her seed — maybe down to which county in Ontario.

However, Ontario Goldenrod is considered distinctive enough to now rate as a species, and its distinguishing characteristics are clearly described: “rather sticky stem and flower head bracts”.

Comparing one of my plants of putative Ontario Goldenrod to the description, it agrees: early bloom time, downy stems on flower heads, tapering, slightly arched panicle, leaves narrowly oblanceolate, not sheathing the stem… Check, check, check. Now for the final test: Are the stems and bracts sticky? (Drumroll, please.) And …. I dunno. A bit gummy. Not as sticky as Sticky False Asphodel, certainly. A close reading of the description advises me that the stems are “slightly sticky”. Are these stems slightly sticky? I guess. Sort of. Thus concludes another great adventure in plant identification.

As a check, I went back to the key to Goldenrods and carefully read both choices at each level and got to, er, not Ontario Goldenrod. I go astray at a point where I have to chose “racemes in axils of leaves which are much shorter than the racemes.” Nope. But then, I am not in Grey-Bruce County looking at a wild plant, either.

Flora of North America, which is calling the plant Solidago simplex var. ontarioensis, gives one of the distinguishing characteristics as “peduncle bracteoles 1-3”. This is really getting into the weeds, if I may use that phrase. But, yes, my plant checks out. It has 3 peduncle bracteoles on the lower peduncles and 1 on the upper peduncles. Spellcheck is objecting to the word “bracteoles” and I am getting fed up with the very sight of the silly green thing in front of me.

Oh, dear. We are all trying to make our gardens livelier and more supportive of wildlife, not doing a doctorate on goldenrods or naturalizing a sensitive area on the Bruce. I think I can still call my plants Ontario Goldenrod. The flowers are not yet open, so perhaps the racemes will elongate as they mature. Also, I cannot get a good look at the bracts until the flowers get a bit larger. I will revisit this when the plants are in full flower.

This gives you an idea of the problems and puzzlements of doing plant identification. Sometimes one needs to revisit the plant at more than one season. Getting a key that pertains to your exact area in not always easy, or even possible. A plant growing in a garden out, even slightly, of its native range, has already lost defining information about range and habitat. Also, naturally occurring hybrids between species are relatively common. If a specimen of, say, Aster, or Goldenrod (two of the more troublesome groups) is giving you a hard time, it may be a hybrid. At some point, we can just leave the questions to be chewed over by professional botanists and note that the plant is doing its job of attracting pollinators and providing food for caterpillars in our gardens. For the most part, ecological connections are similar for plants within a genus, so we can leave geographic variants to the experts.

The featured photo above shows specimen of Ontario Goldenrod I was puzzling over. Please note the coffee cup, the single most important tool for investigations of this kind.