Asteraceae

Asters, daisies, sunflowers, thistles, etc. Generally each “flower” is composed of many miniscule flowers of which there may be two types, tiny “disk” flowers in the middle, and larger “ray” flowers (that often look like normal petals) on the outside. (Some plants have only ray flowers, others only disk, some both types, some have separate male/female flowers where one or the other may not be either ray or disk).

In this coastal tarweed flower you can actually see how the disk flowers are real flowers with five petals. The ray flowers only seem to have one petal (or perhaps several petals fused into one). The branched style is clearly visible at the base of the ray flower, while the fused anthers (in dark purple) are obvious in the middle of the disk flower.

Achillea	Artemisia
Tribe: Anthemideae (Mayweed)
Achillea millefolium Common yarrow Feb–Oct	Artemisia californica Old man’s beard Apr–Oct	Artemisia douglasiana Mugwort June–Sep
Cotula		Matricaria
Cotula australis Southern Brass Buttons Feb–June	Cotula coronopifolia Brass Buttons All year	Matricaria discoidea pineapple weed Feb–May
Tribe: Astereae (Aster)
Baccharis
Baccharis pilularis Coyote Bush July–Dec	Baccharis plummerae Plummer’s Baccharis July–Dec	Baccharis salicifolia Mulefat July–May
Ericameria
Ericameria arborescens goldenfleece Sep–Nov	Ericameria ericoides Mock Heather July–Apr	Ericameria nauseosa Common Rabbit Brush Jan–Feb
Erigeron
Erigeron canadensis Horseweed Apr–Feb	Erigeron foliosus leafy fleabane Apr–Jan	Erigeron bonariensis Flax-leaved Horseweed Feb–Mar
Gutierrezia	Hazardia	Heterotheca
Gutierrezia californica California Matchweed July–Dec	Hazardia squarrosa sawtooth goldenbush July–Jan	Heterotheca grandiflora telegraph weed All year
Heterotheca	Isocoma	Rigiopappus
Heterotheca sessiliflora Hairy Golden Aster July–Oct	Isocoma menziesii Menzies’ goldenbush June–Apr	Rigiopappus leptocladus Wireweed April
Solidago	Symphyotrichum
Solidago velutina California goldenrod All year	Symphyotrichum subulatum Baby’s breath Aster Sep–Jan
Tribe: Cichorieae (Chicory)
Agoseris		Hieracium
Agoseris grandiflora California Dandelion Mar–July	Agoseris heterophylla Mountain Dandelion Apr–June	Hieracium argutum Southern Hawkweed May–Oct
Hypochaeris		Malacothrix
Hypochaeris glabra Smooth Cat’s ear Jan–June	Hypochaeris radicata Hairy Cat’s ear All year	Malacothrix saxatilis Cliff-aster All year
Malacothrix	Microseris	Picris
Malacothrix saxatilis-saxatilis Seaside daisy All year	Microseris lindleyi Silver Puffs Mar–June	Picris echioides Prickly ox-tongue All year
Rafinesquia	Sonchus	Stephanomeria
Rafinesquia californica California Chickory Mar–July	Sonchus sp. Sow-Thistle All year	Stephanomeria cichoriacea Chicory-leaved wire-lettuce June–Jan
Stephanomeria		Taraxacum
Stephanomeria exigua Small Wirelettuce June–Sep	Stephanomeria virgata Tall Stephanomeria June–Feb	Taraxacum officionale Dandelion Feb–Aug
Tragopogon	Lactuca
Tragopogon porrifolius Purple Salsify Apr–Sep	Lactuca serriola Prickly Lettuce May–Jan
Tribe: Coreopsideae (Coreopsis)
Bidens	Leptosyne
Bidens pilosa Beggar’s ticks All year	Leptosyne bigelovii Bigelow coreopsis April
Tribe: Cynareae (Thistle)
Carduus	Centaurea
Carduus tenuiflorus Slender thistle Nov–June	Centaurea melitensis Maltese star thistle Jan–Oct	Centaurea solstitialis Yellow star thistle Mar–Dec
Cirsium
Cirsium occidentale-californicum California thistle May–Aug	Cirsium occidentale-venustum Venus thistle Feb–Aug	Cirsium vulgare Bull thistle Jan–Sep
Silybum
Silybum marianum milk thistle All year
Tribe: Helenieae (Sneezeweed)
Chaenactis	Helenium	Lasthenia
Chaenactis glabriuscula Yellow Pincushion Mar–June	Helenium puberulum Sneezeweed July–Nov	?Lasthenia gracilis Common Goldfields Mar–Apr
Tribe: Heliantheae (Sunflower), Sub-tribe: Ambrosiinae (Ragweed)
Ambrosia
Ambrosia chamissonis beach-bur Jan–Oct	Ambrosia psilostachya Western ragweed May–Jan	Ambrosia artemisifolia Common ragweed Aug–Jan
Xanthium
Xanthium spinosum Spiny Clotbur September	Xanthium strumarium Cocklebur Feb–Mar
Tribe: Heliantheae (Sunflower), Sub-tribe: Baeriinae (Wooly Sunflower)
Eriophyllum
Eriophyllum confertiflorum golden yarrow All year
Tribe: Heliantheae (Sunflower), Sub-tribe: Eupatorieae
Ageratina	Brickellia
Ageratina adenophora sticky snakeroot Feb–Oct	Brickellia californica California Brickellbush May–Dec
Tribe: Heliantheae (Sunflower), Sub-tribe: Heliantheae (Sunflower)
Encelia	Venegasia
Encelia californica Bush sunflower All year	Venegasia carpesioides canyon sunflower All year
Tribe: Heliantheae (Sunflower), Sub-tribe: Madiinae (Tarplant)
Centromadia	Deinandra
Centromadia parryi Southern tarplant May–Feb	Deinandra fasciculata clustered tarweed Apr–Dec	Deinandra increscens Grassland tarweed July–Jan
Layia	Madia
Layia platyglossa Tidy Tips April	Madia elegans Common Madia June–Nov	Madia gracilis slender tarweed Apr–July
Madia
Madia sativa Coast tarweed May–Oct
Tribe: Inuleae (Everlasting)
Micropus	Pseudognaphalium
Micropus californicus Slender cottonweed April	Pseudognaphalium beneolens fragrant everlasting Dec–May	Pseudognaphalium biolettii twocolor cudweed Aug–May
Pseudognaphalium
Pseudognaphalium californicum California pearly everlasting Jan–Nov	Pseudognaphalium canescens white everlasting January
Tribe: Nassauvieae
Acourtia
Acourtia microcephala Sacapelote May–Aug
Tribe: No Tribe
Jaumea
Jaumea carnosa Fleshy Jaumea May–Oct
Tribe: NoTribe
Corethrogyne	Lepidospartum
Corethrogyne filaginifolia California Aster July–Feb	Lepidospartum squamatum Scalebroom September
Tribe: Senecioneae (Senecio)
Delairea	Senecio
Delairea odorata Cape Ivy Nov–May	Senecio flaccidus threadleaf ragwort June–Nov	Senecio vulgaris Old man of Spring Feb–May