Asteraceae - Aster Family

Asteraceae - Aster or Composite Family

The Asteraceae are the largest family of vascular plants on the earth with over 1000 genera and 20,000 species worldwide. There are 2500 species alone in North America.
The family is easily recognized by clusters of flowers sitting on a head or receptacle. What appears to be a single flower is actually clusters of many small flowers, called ray flowers and disk flowers. The disk flowers grow in the center and the ray flowers around the outside. Some species like chicory and dandelions have only ray flowers, thistles have only disk flowers and species like sunflowers have both types. The lobes of the ray flowers are longer, expanded to resemble a single petal, and are called rays. The receptacle is covered on the outside with several bracts, together forming an involucre.
A tuft of fine hairs or bristles, called pappus, often grows from the top of the fruit. This may enlarge into a plume of hairs to aid in wind dispersal. The fruits themselves are dry and hard, a type known to botanists as achenes.

General Key to Identify which Major Group of Genera a Species Belongs to
(Note: These groups are based on plant appearance only)

FLOWERHEADS WITH RAYS
Sunflower group A very large group of perennial or annual plants from many genera. Flowerheads grow individually and have rays which are comparatively wide. Disk flowers are arranged in a distinctive head in the middle.
Fleabane group This group consists of the genus Erigeron, Fleabanes. Flowerheads grow individually, with rays which are very narrow and numerous. Disk flowers are arranged in a distinctive head in the middle.
Dandelion group Plants of this group usually contain milky juice, Flowerheads have ray flowers only and often seeds with large, feathery plumes. Genera included are Dandelions, Salsify, Chichory, Lettuce and Hawkweeds.
Goldenrod group Perennials with small flowerheads, growing in dense clusters. Flowerheads have both small rays and disk flowers in the middle. This group consists of Goldenrods and Coltsfoot.
FLOWERHEADS WITHOUT RAYS
Thistle group Mainly tall, robust plants with spines on stalks and leaves. Flowerheads are usually purple, and may be covered by spiny hooks. This groups consists of Thistles, Burdocks and Cocklebur.
Pussytoes group Small plants, often growing in the mountains. Flowerheads small, usually white, in very dense, round or flat-topped clusters. Large group, including Pussytoes, Yarrow and Pearly Everlasting.
Sagewort group Often slender, aromatic plants growing in dry areas. Flowerheads numerous, very small, in dense, tall and narrow clusters. This group consists of Sageworts, Mugworts and Wormwoods.
Group with compact, button-like flowerheads Plants with no ray flowers and disk flowers which are very short. Flowerheads are compact, cone-shaped or button-like. Plants included are Mayweed, Tansy and Coneflower.
Group with disk flowers more loosely arranged Plants with no ray flowers and relatively long, loosely arranged disk flowers. Flowerheads are growing individually or in clusters, but not in compact heads. Plants included are Knapweed, Blazingstar, Dusty Maiden and Boneset.

Below is an alphabetical listing with links to presented species of the Aster family:

Scientific Name	English Name

Achillea A. millefolium Agoseris A. aurantiaca A. glauca Anaphalis A. margaritacea Antennaria A. lanata A. rosea Arctium A. minus Arnica A. chamissonis A. cordifolia A. parryi Artemisia A. dracunculus A. frigida A. ludoviciana Aster A. ascendens A. conspicuus A. ericoides A. falcatus A. integrifolius A. meritus Balsamorhiza B. sagittata Bidens B. cernua Brickellia Carduus C. nutans Centaurea C. maculosa Chaenactis Cichorium Cirsium C. arvense C. foliosum C. vulgare Coreopsis C. tinctoria Crepis Erigeron E. acris E. compositus E. speciosus Eriophyllum E. lanatum Eucephalus E. engelmannii Gaillardia G. aristata Gnaphalium Grindelia G. squarrosa Gutierriza Helianthella H. quinquenervis H. uniflora Helianthus H. annuus H. nuttallii Heterotheca H. villosa Hieracium H. albiflorum H. cynoglossoides Hulsea H. algida Iva Lactuca L. biennis L. serriola L. tatarica Leucanthemum L. vulgare Liatris L. punctata Matricaria M. discoidea Microseris Oreostemma O. alpigenum Ratibida R. columnifera Rudbeckia R. occidentalis R. laciniata Senecio S. fremontii S. integerrimus S. triangularis Solidago S. gigantea S. missouriensis S. multiradiata Sonchus Stenotus S. acaulis Tanacetum T. vulgare Tetraneuris T. acaulis Townsendia Townsendia hookeri Townsendia parryi Tragopogon T. dubius T. pratensis Tripleurospermum T. maritima Xanthium	Yarrow Yarrow False Dandelion Orange Agoseris False Dandelion Pearly Everlasting Pearly Everlasting Pussytoes Woolly Pussytoes Rosy Pussytoes Burdock Common Burdock Arnica Leafy Arnica Heart-leaved Arnica Parry's Arnica Sagebrush, Wormwood, Tarragon Tarragon Prairie Sagewort Western Mugwort Aster Long-leaved Aster Showy Aster Heath Aster Cluster Aster Thick-stemmed Aster Arctic Aster Balsamroot Arrow-leaved Balsamroot Beggartick Nodding Beggartick Thoroughwort Thistle Nodding Thistle Knapweed, Cornflower Spotted Knapweed Dusty Maiden Chicory Thistle Canada Thistle, Creeping Thistle Elk Thistle, Leafy Thistle Bull Thistle Tickseed Golden Tickseed Hawksbeard Fleabane Northern Fleabane Cut-leaved Fleabane Showy Fleabane Woolly Sunflower Woolly Sunflower Engelmann's Aster Engelmann's Aster Brown-eyed Susan, Blanket Flower Brown-eyed Susan Cudweed, Everlasting Gumweed Curly-cup Gumweed Snakeweed Little Sunflower Five-nerved Little Sunflower One-flowered Little Sunflower Sunflower Common Sunflower Nuttall's Sunflower Golden Aster Golden Aster Hawkweed White Hawkweed Houndstongue Hawkweed Hulsea Alpine Hulsea - Lettuce Tall Blue Lettuce Prickly Lettuce Blue Lettuce Daisy Oxeye Daisy Blazingstar, Gayfeather Dotted Blazingstar Camomile, Pineapple Weed Pineapple Mayweed Microseris Aster Alpine Aster Prairie Coneflower Prairie Coneflower Coneflower Western Coneflower Cut-leaved Coneflower Groundsel Rock Groundsel Western Groundsel Arrow-leaved Groundsel Goldenrod Giant Goldenrod Missouri Goldenrod Northern Goldenrod Sow Thistle Goldenweed Stemless Goldenweed Tansy Common Tansy Alpine Sunflower, Hymenoxys Stemless Hymenoxys Townsendia Hooker's Townsendia Parry's Townsendia Salsify Yellow Salsify Meadow Salsify Scentless Mayweed Scentless Mayweed Cocklebur

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Contents

English Names Index

Scientific Names Index

Family Index