A memoir of Admiral Dahlgren by his widow was published at Boston in 1882. (D. H.)
DAHLGREN, KARL FREDRIK (1791-1844), Swedish poet, was born at Stensbruk in Östergötland on the 20th of June 1791. At a time when literary partisanship ran high in Sweden, and the writers divided themselves into "Goths" and "Phosphorists," Dahlgren made himself indispensable to the Phosphorists by his polemical activity. In the mock-heroic poem of _Markalls sömnlösa nätter_ (Markall's Sleepless Nights), in which the Phosphorists ridiculed the academician Per Adam Wallmark and others, Dahlgren, who was a genuine humorist, took a prominent part. In 1825 he published _Babels Torn_ (The Tower of Babel), a satire, and a comedy, _Argus in Olympen_; and in 1828 two volumes of poems. In 1829 he was appointed to an ecclesiastical post in Stockholm, which he held until his death. In a series of odes and dithyrambic pieces, entitled _Mollbergs Epistlar_ (1819, 1820), he strove to emulate the wonderful lyric genius of K. M. Bellman, of whom he was a student and follower. From 1825 to 1827 he edited a critical journal entitled _Kometen_ (The Comet), and in company with Almqvist he founded the _Manhemsförbund_, a short-lived society of agricultural socialists. In 1834 he collected his poems in one volume; and in 1837 appeared his last book, _Angbåts-Sånger_ (Steamboat Songs). On the 1st of May 1844 he died at Stockholm. Dahlgren is one of the best humorous writers that Sweden has produced; but he was perhaps at his best in realistic and idyllic description. His little poem of _Zephyr and the Girl_, which is to be found in every selection from Swedish poetry, is a good example of his sensuous and ornamented style.
His works were collected and published after his death by A. J. Arwidsson (5 vols., Stockholm, 1847-1852).
DAHLIA, a genus of herbaceous plants of the natural order Compositae, so called after Dr Dahl, a pupil of Linnaeus. The genus contains about nine species indigenous in the high sandy plains of Mexico. The dahlia was first introduced into Britain from Spain in 1789 by the marchioness of Bute. The species was probably _D. variabilis_, whence by far the majority of the forms now common have originated. The flowers, at the time of the first introduction of the plant, were single, with a yellow disk and dull scarlet rays; under cultivation since the beginning of the 19th century in France and England, flowers of numerous brilliant hues have been produced. The flower has been modified also from a flat to a globular shape, and the arrangement of the florets has been rendered quite distinct in the ranunculus and anemone-like kinds. The ordinary natural height of the dahlia is about 7 or 8 ft., but one of the dwarf races grows to only 18 in. With changes in the flower, changes in the shape of the seed have been brought about by cultivation; varieties of the plant have been produced which require more moisture than others; and the period of flowering has been made considerably earlier. In 1808 dahlias were described as flowering from September to November, but some of the dwarf varieties at present grown are in full blossom in the middle of June.