University of Guam

[ Malvaceae ] [ Brassicaceae ] [ Cucurbitaceae ] [ Fabaceae ] [ Solanaceae ] [ Asteraceae ]

[Asterids: Campanulids]
Asteraceae (daisy family)

Arnica montana (the source of the medicinal arnica), displaying disk and ray florets. (Photographed in Austria)

On-line sources

U. Wisconsin Plant Systematics: Asteraceae

Texas A&M (Manhart): Asteraceae

Plants of Guam on-line: Pluchea; Wollastonia [as Wedelia].

 

Characteristics of the family

One of the largest and most distinctive families. The most familiar example here, probably, is Bidens alba, the "Guam daisy" or beggars'-ticks.

 "Flowers" are actually very tight inflorescences in which the fertile flowers are the little tubular ones (disc flowers) clustered in the middle (see photo above). Around the edge of the inflorescence is a ring of sterile ray flowers, each with a single petal. What we commonly refer to as the seeds are actually individual dry fruit, with one seed inside. When you shell a sunflower seed, you are taking off the fruit wall.

Sunflower.