This section is from the book "Handbook Of Hardy Trees, Shrubs, And Herbaceous Plants", by W. Botting Hemsley. Also available from Amazon: Handbook of hardy trees, shrubs, and herbaceous plants.
Perennial herbs with alternate leaves and terminal panicles of pale blue flowers. Corolla-lobes narrow. Anthers naked. Carpels or follicles long and narrow; seeds naked. Other characters the same as in Vinca. This genus consists of five or six North American species, and was named after an American traveller of some note.
A. salicifolia has a less erect habit, smaller flowers, and lanceolate leaves; and A. ciliata linear leaves.