Oleander
2 of the 6 encyclopedias on this shelf carry an entry for Oleander. Both are reproduced below, so you can see where they agree and where they differ.
Aiton's Encyclopedia (1910)
an old-fashioned, milky-juiced, decorative shrub. There are two or three species. The common oleander is a native of the Mediterranean region. In the Bermudas it is a hedgerow bush twenty-five feet high. In the Southern States it is a favorite garden shrub. In the North it is grown in tubs and is a favorite, as it requires little attention and its blossoming season is long. The tub holding the plant is set out of doors during the summer. After the blossoming is over it is transferred to the cellar or other convenient place where neither frost nor a strong light will reach it. It may also be made to blossom indoors in the winter like other house plants. The oleander is grown easily from cuttings. Its chief enemy is the plant scale. The house plant is much branched and attains a height of seven to fifteen feet. The flowers are salver-shaped and fragrant; white, red, scarlet, yellow, pink in color. The leaves are lanceolate and leathery. They are poisonous and should not be within reach of young children.
Collier's New Encyclopedia (1921)
in botany, Nerium oleander, the common, and N. odorosum, the sweet-scented oleander. They have lanceola coriaceous leaves, with parallel veins and fine roseate flowers. The former is a native of India, now naturalized in many warm countries. A decoction of its leaves forms a wash used in the S. of Europe to destroy cutaneous vermin; the powdered wood and bark are used at Nice OLEANDER as the basis of a rat poison. Sweet scented oleander is wild in Central India, Scinde, Afghanistan, and the outer Himalayas to 5,500 ft. Often cultivated in India, etc. All parts of the plant, especially the root, are poisonous.
What Has Changed in the Last Century
The horticulture holds up: oleander is still an easy, long-blooming tub plant in cold regions and a hedge shrub in the South, and it is still raised from cuttings. Botanists have simplified the genus that Collier's split in 1921 into "the common" and "the sweet-scented" oleander reated as one species, Nerium oleander, with N. odorum/odorosum reduced to a synonym; its native range is now given as the Mediterranean through southwest Asia rather than India, where it is long naturalized. The poison the accounts warn of has been named cardiac glycosides, chiefly oleandrin, which act on the heart much like digitalis; serious human poisonings are rarer than the old warnings imply and can now be treated in hospital. Aiton's 1910 verdict that "its chief enemy is the plant scale" has been overtaken in the American Southwest by oleander leaf scorch, caused by the bacterium Xylella fastidiosa and spread by the glassy-winged sharpshooter, which has killed large numbers of roadside plantings in California since the 1990s.
Written for this edition, 2026.