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ASTERACEAE (Compositae) Composite Family. Leaves : alternate or opposite, mostly simple, usually toothed or lobed, texture coarse, rough. Inflorescences: heads ( capitula ), each of which is surrounded by an involucre of bracts called phyllaries. involucre. phyllary. Receptacle.
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Leaves: alternate or opposite, mostly simple, usually toothed or lobed, texture coarse, rough
Inflorescences: heads (capitula), each of which is surrounded by an involucre of bracts called phyllaries
involucre phyllary
Florets (flowers) of three general types: • Disc florets – these are actinomorphic, often perfect • Ray florets – these are zygomorphic, often pistillate or sterile • Ligulate florets – these are zygomorphic, usually perfect
Corolla of five fused petals Androecium of five stamens, these fused by their anthers, surrounding the style Disc florets Ovary inferior, gynoecium of two fused carpels
Ray floret Ligulate head and floret
Inflorescence structure: • Heads radiate – both ray and disc • florets • Heads discoid – all disc florets • Heads ligulate – all ligulate florets
An achene is a dry, indehiscent, one-seeded fruit . Fruit an achene
Economic Importance: food (sunflower seeds, artichokes, lettuce), ornamentals (zinnias, dahlias, cosmos, marigolds, chrysanthemums, sunflowers …), pyrethrum, echinacea
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Making Sense of Diversity: New England Tribes of the Aster Family
CichoreaeChickory Tribe Chickory (non-native) Panicled hawkweed Tribe characters: Heads ligulate; sap milky
CynareaeThistle Tribe Burdock (non-native) Spotted knapweed (non-native) Tribe characters: Heads discoid, involucre spiny
EupatorieaeBoneset Tribe White snakeroot Spotted Joe-pye weed Tribe characters: Heads discoid; leaves opposite or whorled
Inuleae,Everlasting Tribe Pearly everlasting Cudweed Tribe characters: Heads discoid, involucres papery, white
Heliantheae,Sunflower Tribe Cosmos (non-native) Burr marigold Woodland sunflower Tribe characters: Heads radiate, receptacle chaffy; lvs. opposite
Anthemideae,Chamomile Tribe Pineapple weed (non-native) Dog chamomile (non-native) Tansy (non-native) Tribe characters: Leaves finely dissected, aromatic
Senecioneae,Ragwort Tribe Coltsfoot (non-native) New England arnica Tribe characters: Heads radiate, phyllaries uniseriate; leaves alternate
Astereae,Aster tribe Fleabane Blue-stemmed goldenrod New England aster Tribe characters: Heads radiate, phyllaries multiseriate; leaves alternate