Flower-heads. - Composed of blue or purple ray-flowers, with a centre of yellow disk-flowers.
As about one hundred and twenty different species of aster are native to the United States, and as fifty-four of these are found in Northeastern America, all but a dozen being purple or blue (i.e., with purple or blue ray-flowers), and as even botanists find that it requires patient application to distinguish these many species, only a brief description of the more conspicuous and common ones is here attempted.
Along the dry roadsides in early August we may look for the bright blue-purple flowers of A. patens. This is a low-growing species, with rough, narrowly oblong, clasping leaves, and widely spreading branches, whose slender branchlets are usually terminated by a solitary flower-head.
Probably no member of the group is more striking than the New England aster, A. Novoe Anglioe, whose stout hairy stem (sometimes eight feet high), numerous lance-shaped leaves, and large violet-purple or sometimes pinkish flower-heads, are conspicuous in the swamps of late summer.
A. puniceus is another tall swamp-species, with long showy pale lavender ray-flowers.
One of the most commonly encountered asters is A. cordifo-lius, which is far from being the only heart-leaved species, despite its title. Its many small, pale blue or almost white flower-heads mass themselves abundantly along the wood-borders and shaded roadsides.
Perhaps the loveliest of all the tribe is the seaside purple aster, A. spectabilis, a low plant with narrowly oblong leaves and large bright heads, the violet-purple ray-flowers of which are nearly an inch long. This grows in sandy soil near the coast and may be found putting forth its royal, daisy-like blossoms into November.
Great Britain can claim but one native aster, A. Tripolium, or sea-starwort as it is called. Many American species are cultivated in English gardens under the general title of Michaelmas daisies. The starwort of Italy is A. amellus. The Swiss species is A. Alpinum.
This beautiful genus, like that of the golden-rod, is one of the peculiar glories of our country. Every autumn these two kinds of flowers clothe our roadsides and meadows with so regal a mantle of purple and gold that we cannot but wonder if the flowers of any other region combine in such a radiant display.