Botanic Names: On the (Leaf) Edge

Some plants’ botanic names describe edges, mostly of their leaves. Smooth leaf edges are termed “entire” and rarely find their way into botanic names. Aureolaria laevigata, Entire-leaf Yellow False Foxglove, is an exception. However, “laevigata” just means “smooth” and does not guarantee entire leaves. As an example of a plant that is smooth but doesn’t have entire leaves, The Flora of Virginia describes the leaves of Boechera laevigata, Smooth Rock Cress, as “serrate to dentate or pinnately dissected or lobed.” All of those adjectives turn up in botanic names somewhere or other.

An otherwise entire leaf may come to a short, sharp, slender, abrupt point, in which case it is termed “mucronate” as in Atriplex mucronata, Sea-beach Orach. Mucronate tips also can be found on tepals.

Simple teeth on the leaf edge are dentate, as in Viburnum dentatum, Arrowwood Viburnum, Castanea dentata, American Chestnut, Populus grandidentata, Big-tooth Aspen or even Ambrosia bidentata, “twice toothed” Lance-leaved Ragwort.

Little teeth may be called serrate, or you can make the teeth even smaller by adding a “ul” in there, as in Alnus serrulata, Smooth Alder, or Hypericum denticulatum, Coppery St. John’s-wort, though the St. John’s-wort tiny teeth are on the edges of its petals instead of its leaves.

Leaves with rounded teeth are crenate. The only example of this term in a botanic name I could find is Japanese Holly, *Ilex crenata, and its leaves are only sometimes crenate, sometimes entire.

Leaf edges may be turned under, as in Thalictrum revolutum – this does not translate to “revolting” even though its common name is Skunk Meadow-rue. Or they may be curled, “crisped,” as in Curly Dock, *Rumex crispus.

Leaves with deeply jagged edges may be called “laciniate” – think lacy or lacerated. Examples are Rudbeckia laciniata, the Cut-leaf or Green-headed Coneflower, and *Dipsacus laciniatus, Cut-leaf Teasel. Or they may be called “dissected”, as in Cardamine dissecta, formerly Dentaria multifida, Fork-leaf Toothwort (which has biternate leaves: divided into three leaflets, each of which is divided into three again) or Sceptridium dissectum, formerly Botrychium dissectum, the Cut-leaf Grape Fern. And if the leaves really get divided beyond what anyone wants to count, they may be called “thousand-leaved” as in Achillea millefolium, Common Yarrow.


Margaret Chatham