Six Plant Families to Get to Know in Winter
by Carol Levine • Winter 2000 (Volume 27, no. 4)
The placement of specimens into plant families can be a difficult job when using the winter remnants. Families are grouped according to their reproductive morphology rather than other structures in the plant. In many instances, however, the winter remnants have lost essential parts of the reproductive structures. But, not to be discouraged, there are some families that retain enough characteristics in winter so that they still can be identified with some ease.
One family in particular that can easily be identified in winter is the Mint family (Lamiaceae, Labiatae). The branching is opposite, the stems are generally square, and the calyx remains on the stem after the petals have fallen. The calyx is tubular and lobed. End of story? No. There are a few plants that have all the above characteristics but are not members of the Mint family.
To make sure we have to go further and look into the ovary at the base of the calyx. If inside the base of the calyx we see four little nutlets, then we know we have a mint. On the other hand, if we discover there are actually two chambers to the ovary and each chamber contains numerous seeds, then we have to look further to the Figwort family (Scrophulariaceae). The Figwort family is a lot more variable than the mints. This family may have species with square or round stems, and opposite or alternate branches. But always the ovary is two-chambered with many seeds in contrast to four nutlets.
Another family that still comes together fairly well in winter is the Carrot family (Apiaceae, Umbelliferae). The floral remnants are characterized by inverted umbrella shapes known as umbels. Since the remnants of many Apiaceae appear quite similar in their winter state, it is helpful to find fruits still clinging to the umbels and to identify the species from these. The leaves are chiefly alternate or basal and the stems of the leaves are dilated to a sheathing base forming a bulge. The bulges and wrap-around leaf scars remain in winter. The stems are usually hollow and grooved.
Plants in other families that grow in umbels differ in various ways. In plants like the Alliums in the Lily family or Aralia spp in the Araliaceae, there would not be bulging wraparound leaf scars on the stems to the inflorescence.
The Orchid family (Orchidaceae) commonly has fruits and fruit remnants that typify the family. These fruits are three-parted capsules but the fruits of most of them stay closed at each end and open by slits along the sides. Their seeds are tiny and look like dust.
The fruit of the Mustard family (Brassicaceae, Cruciferae) is a unique type called a silique. Siliques can take many kinds of shapes (Iong and narrow, short and rounded) but they are always two-chambered with a thin septum in the middle and seeds on both sides. As time goes on and the seeds open, the outer walls fall off, and the seeds disperse. All that is left on the plant is the center septum, which is often silvery or translucent. This is one of the few families in which the members are identified more easily by their fruits than by their flowers.
Our sixth family is the Bean family (Fabaceae, Leguminosae). This family is typified by its fruit called either a pod or a legume or, in the case of Desmodium spp, a loment. These pods are single-chambered, bilaterally symmetrical and open along one or two seams, the full length of the fruit. Many have seeds lined up along one edge like a pea pod.
Here is the challenge to begin to organize our thoughts in regard to wildflowers in winter. It is not as difficult as it first appears to be because there are certain plant groups that do fall together and lead you down the path to identification.