Observations of the Month: Pluchea (Asteraceae)

Salt Marsh Fleabane (Pluchea odorata var. odorata) https://www.inaturalist.org/observations/34415150 by @nora32
Arrow Weed (Pluchea sericea) https://www.inaturalist.org/observations/24209934 by @aarft

Noël-Antoine Pluche was an 18th century French priest and naturalist who wrote a nine-volume work called Le Spectacle de la Nature. San Diego County is home to two plant taxa in a genus that was named for him: Pluchea odorata var. odorata, commonly known as Salt Marsh Fleabane, and Pluchea sericea, commonly known as Arrow Weed. The two are somewhat similar with pinkish-purple flower heads and both can be found in saline soils, but their differences far outnumber their similarities. Salt Marsh Fleabane is an annual or perennial herb which rarely exceeds about a meter in height. Arrow Weed is an upright shrub that may be as tall as 5 meters. Salt Marsh Fleabane has a sweet scent and is sticky to the touch. Arrow Weed has no scent and is not sticky, but instead feels soft due to smooth silky hairs. Salt Marsh Fleabane's ovate leaves are fairly broad, toothed, attached to the stems by petioles, and spaced out along the stem. Arrow Weed's more narrow, lanceolate, entire leaves hug the stems and are crowded together. You will find both plants in coastal San Diego but Arrow Weed is expected in the desert where there are only a few records of Salt Marsh Fleabane. When you find either of these plants, you can think of it as one of Abbé Pluche's spectacles of nature.

Posted on 03 de janeiro de 2020, 05:49 PM by milliebasden