Composite / Daisy Family — Asteraceae

The daisy, or composite, family is the second largest family of flowering plants, with over 20,000 species worldwide. Familiar members include dandelion, marigold, and daisy, not to mention lettuce, endive, sunflower, and thistle. Members of this cosmopolitan family are widespread, inhabiting many environments. It is well represented in the Canadian Arctic with more than 56 species in 14 genera.

Composite flowers are generally yellow, bluish-purple, orange, white, or pink. They are characterized by the fact that the "flowers" are not really flowers at all – a sunflower or daisy, for example, is actually a conglomeration of dozens to hundreds of tiny, individual flowers – called disc flowers – packed into a "head". The flowers lining the outer margin – called ray flowers – each have a single, overdeveloped petal; it is these unusually large petals that form the outer ring of what appears to be the "petals" of a single large "flower". After the flowers have finished blooming, a familiar "fluffy" head appears. Each hair of the soft fuzz is the result of a single flower producing a seed.

The three most diverse genera of composites in the Arctic are: pussytoes, Antennaria, groundsels, Senecio, and fleabanes, Erigeron. Pussytoes are named for the grey, woolly, or silky hairs that cover their flowers, resembling the furry paws of a small cat. This trait is common among many high-latitude plants, perhaps as a joint adaptation to protect against the sun's radiation and to trap air for warmth. Plants in this genus are also commonly called "everlastings", referring to the foliage that persists well into winter, failing to fade to the typical brown of most other dying plants. All Antennaria flowers are tubular, but clustered or solitary.

Species of groundsels are hard to distinguish from members of other genera in this family. A large and complex genus, it contains a variety of plants from herbs to shrubs, and even tree-like species. Both the ray and disc flowers of most arctic species are yellow or orange, and disc flowers bear tubular petals. Some species lack ray flowers and resemble a daisy that has had its "petals" picked. One species, the northern groundsel, Senecio hyperborealis, is endemic to the Arctic Cordillera ecozone. This is the only place in the world that this species exists!

Fleabanes are obvious daisies, bearing a fringe of myriad narrow ray petals that encircle a large head of disc flowers and range in colour from white to pale lilac. Cutleaf fleabane, Erigeron compositus, is the only arctic fleabane with lobed leaves, while mountain fleabane, E. humilis, is distinguishable by the presence of purple-black, curly hairs around the calyx. The largeflower fleabane, E. grandiflorus, is another species endemic to the Arctic Cordillera.

Dwarf hawksbeard, Crepis nana, has numerous bright, yellow flowers that look like miniature dandelions. Its spoon-shaped leaf blades have cavities filled with a milky juice that acts as a defence against hungry insects. Dwarf hawksbeard is a plant that is well adapted to the rigors of the Arctic; since the growing season is so short, this plant has adopted a habit of blooming while the flower heads still touch the basal rosette of leaves – essentially, they lack stems! This adaptation keeps the developing seeds close to the ground, where the warmest layer of air is located.

Taraxacum sp.

Dandelions, Taraxacum spp., are consumed throughout the world as a salad green and their flowers are used to make wine. Their common name comes from the French dente de lion, meaning "tooth of the lion" in reference to the basal rosette of toothed leaves. Dandelions contrast the groundsels in that their flowers bear only ray petals – there are no disc flowers. The northern dandelion, T. pumilum, is restricted to the Arctic and even occurs as far north as the northernmost edge of Ellesmere Island. It produces a single, dark yellow flowerhead atop a leafless, hollow stem. Like all other dandelions, the stem contains a bitter, milky sap.