This section is from the book "The Botanical Magazine; Or, Flower-Garden Displayed", by William Curtis. Also available from Amazon: The Botanical Magazine; or, Flower-Garden Displayed, Volume I.
Dracocephalum Denticulatum. Toothed Dragon's-Head.
Corollae faux inflata: labium superius concavum.
DRACOCEPHALUM denticulatum floribus spicatis remotis, foliis obovato-lanceolatis superne denticulatis. Ait. Kew. V. 2. p. 317.
About the year 1786, we received from Philadelphia, seeds of a plant collected at a considerable distance from that city, announced to us as new and rare, and which produced the present species of Dracocephalum: Mr. Watson, Nurseryman at Islington, obtained the same plant from Carolina, about the same period.
It is a hardy perennial, multiplying considerably by its roots, which creep somewhat; it must be planted in a moist soil, and shady situation, for such it affects, and in such only will it thrive.
It flowers in August and September.
It bears a considerable affinity to the Dracocephalum virginianum, to which, though a much rarer plant, it is inferior in point of beauty; it spreads more on the ground, its flowering stems are not altogether so upright, nor so tall, the leaves are broader, and the flowers in the spikes less numerous.