- Author: John Madsen
- Posted by: Guy B Kyser
We were sampling plots in the Delta in July 2016, and found a small clump of this plant – pickerelweed (Pontederia cordata). Generally considered a desirable native wetland plant, it happens to fall in the same botanical family as the baddest of the bad in the Delta – waterhyacinth (Eichhornia crassipes). What does family mean in the botanical world, anyway? Although native here, pickerelweed is at best considered “occasional” in the Delta. Waterhyacinth falls somewhere between “abundant” and a “scourge,” depending on the year of reference. While there are a number of similarities in appearance (particularly in the characteristics of the flower, which is the original basis of splitting species into families), these plants do not “behave” at all alike.
We would like to see more of pickerelweed in the Delta – and a lot less of waterhyacinth.
John Madsen, USDA ARS, Davis, CA
In biological classification, family (Latin: familia, plural familiae) is one of the eight major taxonomic ranks; it is classified between order and genus. A family may be divided into subfamilies, which are intermediate ranks above the rank of genus. In vernacular usage, a family may be named after one of its common members; for example, walnuts and hickory trees belong to the family Juglandaceae, commonly known as the walnut family.
What does or does not belong to a family—or whether a described family should be recognized at all—are proposed and determined by practicing taxonomists. There are no hard rules for describing or recognizing a family, or any taxa. Taxonomists often take different positions about descriptions of taxa, and there may be no broad consensus across the scientific community for some time. Some described taxa are accepted broadly and quickly, but others only rarely, if at all; the publishing of new data and opinion often enables adjustments and consensus over time.