The “Kershaw and Allen” Guides to Botanical Identification

The 2025 Vascular Flora of Alberta: An Illustrated Guide and its earlier editions have now become the standard textbook for university students taking botany courses and for serious botanists. It is a much-needed update (albeit without descriptions) from the 1982 Flora of Alberta by E.H. Moss, edited by J.G. Packer. While I recommend that everyone should try using them, keys can be difficult and frustrating to use, especially without access to magnification or comparison material that would allow one to evaluate characters. 

For the less experienced botanist and learner, however, I do think the volume Vascular Flora of Alberta: Illustrations and Maps. can be well worth the purchase. (After all, most of us start by looking at pictures!) It provides larger drawings, and as well includes subspecies and varieties (not included in the key guide for reasons of space), although good illustrations could not always be found for infraspecific taxa.

Equally importantly, the volume provides range maps for each species, which can be helpful in confirming identifications. If you have identified a species and its range does not overlap with the area in which you found it, it is time to think again!

In the illustrations and maps volume, species are arranged in alphabetical order by scientific name, so with that you can easily look up the illustration. While an alphabetical Latin ordering means that related plants, i.e., those in the same genus, will occur together, it does not always mean that the most similar species are placed together, whereas this is often evident in the key. An example is the very similar species Carex bebbii and Carex crawfordii.  The illustration of Carex bebbii may not prompt you to check Carex crawfordii a couple of pages over, although the need to distinguish between the two is evident in the key on pages 446-447 of the 2025 Vascular Flora of Alberta: An Illustrated Guide.. 

If you have only a common name you can refer to the index of common names to find the appropriate page.

There are potential problems with old Latin names, however. I looked up Kochia scoparia, summer-cypress, and could not find it because its new name is Bassia scoparia. I located the new name by reference to the key volume, because that includes recent synonyms, both in the text and in the index, and I could have done likewise in Canadensys Vascan. Knowing the common name summer-cypress, however, will not help you in the key guide as it does not include common names. (Needless to say, I have both volumes, and I still refer to Moss’s Flora of Alberta for descriptions). 

Summer-cypress (Bassia scoparia) growing on bentonite on the slopes of the Sturgeon River at Gibbons. A native of Eurasia, it is often seen on city waste ground as a weed. It has undergone several name changes, from Linnaeus’ original Chenopodium scoparium (in the family Chenopodiaceae) to Kochia scoparia to Bassia, now in the Amaranthaceae. Photo: P. Cotterill

One small drawback detracting from the completeness of the volumes was the authors’ decision to exclude hybrids for reasons of space. (The key volume, at least, is still handy enough to take in the field.) An example is vine-leaved coltsfoot, Petasites frigidus var. xvitifolius, which does not appear in the books, even though it is commonly encountered in our woods and is included in Canadensys Vascan. 

The leaves of vine-leaved sweet coltsfoot, Petasites frigidus var. xvitifolius, a hybrid between two other common varieties of sweet coltsfoot, var. palmatus, palmate-leaved sweet coltsfoot, and var. sagittatus, arrow-leaved sweet coltsfoot. All three varieties are locally common, although the early spring white flower heads only seem to occur frequently in the arrow-leaved plant, a denizen of marshes and ditches; the two other, forest varieties, rely much more on rhizomes for reproductive spread. Photo: P. Cotterill

Quibbles aside, Linda and Lorna have achieved a considerable body of work, of great service to Alberta botanists. They have updated species lists for the province, updated nomenclature, adapted keys from pre-existing keys (no easy task) and chased down illustrations, all done as volunteers outside of academia!

Further, the mode of publishing means that these volumes can be continuously updated, although both authors are “retired” and this could be a task for their successors in the somewhat distant future!  

Patsy Cotterill

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Kershaw, Linda and Lorna Allen 2024. Vascular Flora of Alberta: Illustrations and Maps. Self-published. Kindle Direct Publishing.

Kershaw, Linda and Lorna Allen. 2025. Vascular Flora of Alberta: An Illustrated Guide. Second edition. Self-published.  Kindle Direct Publishing.