“Whose family is yours?”

Centuries ago, that query spurred scholars to name and define every kind of plant or animal they knew. They divided them in groups according to matching traits. Here, we’ll deal with plants.

For instance: rhododendrons and blueberries are in the heath family, formally known as Ericaceae. Again, easily-grown coleus, sage and beebalm each have square stalks (cut any piece of stem and look at its four-sided shape).

That sounds easy, but botanists have found that not all plants can be defined by same shape. The plant-namers, or taxonomists have spent years seeking to settle plants into neat categories: should they be “split” into narrow likenesses or “lumped” into broader categories?

The arguments persist, but in the last few decades, a new field of research has arrived: dividing according to each plant’s DNA (shown in my Merriam-Webster’s dictionary as deoxyribonucleic acid), types of molecules found especially in cell nuclei.

At present, this is the most accurate way of identifying to which family a given plant belongs.

As more and more is discovered about the exact qualities that identify each plant, I find I know less and less. As botanist and gardener, Dr. John Baumgardt wrote in “How to Identify Flowering Plant Families, a Practical Guide for Horticulturists and Plant Lovers” (1982, 1992): “we are far from knowing all ... about plant relationships, about the derivation of species.”

Botanical research is only one field; there’s also zoological work, on land and research happening at Bigelow Laboratory for Ocean Sciences.

Stay tuned.