Asteraceae-Mayweed2017-08-16T12:22:44+00:00

   Asteraceae: Sunflower Family – Anthemideae (Mayweed) Tribe

The Sunflower family is a very large family with over 25,000 members.  Botanists subdivide the family into a number of tribes of which 14 are represented in Monterey County, one of these, the Heliantheae or Sunflower tribe, being further broken down into subtribes of which 9 are represented in Monterey  County. The Mayweed tribe comprises a mixture of obviously daisy-like flowers and others, like some of those on this page as well as the Artemisia, which might not immediately be recognized as belonging to the Sunflower family.

Common Yarrow – Achillea millefolium

Blooms:

Apr–Sept

Plant Height:

3–10 dm

Flower Size:

Large cluster

Origin:

Native

Habitat:

Open places, many communities

Notes:

Very common and immediately distinguishable by its dense, flat-topped clusters of white flowers and long feathery leaves (“millefolium” in the scientific name meaning “thousand-leaved”). Close examination of the individual flowers will reveal the separate ray and disk flowers and a glance at the inflorescence from below will show that the clusters are not structured as umbels despite a superficial likeness of the inflorescence to those found in many members of the Apiaceae (Carrot family).

Mayweed / Dog Fennel – Anthemis cotula

Blooms:

Apr–Aug

Plant Height:

1–6 dm

Flower Size:

Medium

Origin:

Europe

Habitat:

Disturbed areas, coastal dunes, chaparral and oak woodland

Notes:

This plant has 10–15 white ray flowers with a protruding mound of yellow disk flowers.  The ray flowers may become recurved with age.  The aromatic, feathery leaves are distinctive.

Brass Buttons – Cotula coronopifolia

Blooms:

Mar–Dec

Plant Height:

5–40 cm

Flower Size:

Small

Origin:

South Africa

Invasive?

Yes – limited

Habitat:

Mud, moist banks & salt marshes, both coastal & inland

Notes:

A common, appropriately named plant.  It has a seemingly solid yellow disk at the tip of each peduncle comprising many disk flowers and a single series of rayless pistillate flowers on the rim.  The flat hypanthium is distinctive with phyllaries in 2–3 series. Leaves are fleshy, shallowly and irregularly divided.  When crushed, leaves may emit a distinctive aromatic fragrance.

Ox-eye Daisy – Leucanthemum vulgare

Blooms:

July–Aug

Plant Height:

1–3 (10) dm

Flower Size:

Large

Origin:

Europe

Invasive?

Yes – moderate

Habitat:

Waste places & fields

Notes:

Widely naturalized, this daisy has an erect stem  with one to a few large inflorescences, each with 13–34 white ray flowers up to 2 cm long.  Involucre is a flattish hemisphere. Leaves are alternate, obovate to spoon-shaped and coarsely serrated.

Pineapple Weed – Matricaria discoidea

Blooms:

Apr–Aug

Plant Height:

10–30 cm

Flower Size:

Small

Origin:

Native

Habitat:

Riverbanks & disturbed areas

Notes:

A common, low-growing weed with pinnately lobed leaves with linear segments.  There are many flowers in discoid heads, i.e with no ray flowers.  These give off a pineapple aroma when crushed.  The plant is said to act as a short-term insect repellent.

Feverfew – Tanacetum parthenium

Blooms:

June–Aug

Plant Height:

< 10 dm

Flower Size:

Medium

Origin:

Europe

Habitat:

Garden escape in waste areas

Notes:

Two separate forms are found, those with the normal yellow disk flowers and the “Plenum” form with more series of ray flowers and a less clear distinction between the ray and disk flowers. Note the chrysanthemum-like leaves.