Heterotheca


Heterotheca, are North American plants in the sunflower family.

Etymology

Heterotheca comes from Ancient Greek ἕτερος héteros "other, different" and θήκη thḗkē "case, chest", and refers to the fact that, in some species in the genus, the cypselae of the disk and ray florets have different shapes.

Description, biology

These are annual and perennial herbs bearing daisy-like flower heads with yellow disc florets and usually yellow ray florets, associated with mesic to xeric habitats across North America. Several species now included in Heterotheca were previously classified in the genus Chrysopsis
Heterotheca species are often used as food plants by the larvae of some Lepidoptera species including Schinia lynx, Schinia nubila and Schinia saturata.

Chemistry

The leaf volatiles from which the name "camphorweed" is derived include camphor, but as a minor constituent ; of the 41 documented volatiles in a study of Heterotheca subaxillaris, for example, caryophyllene, pinene, borneol, myrcene, and limonene each comprised over 5% of the total.

Species

Sources:

Formerly included

Many species have been included in Heterotheca at various times in the past, but now regarded as more suitable for other genera. The most common of these is Chrysopsis, but others include Aster Bradburia Osbertia Munnozia Pityopsis + Tomentaurum.