a. and sb. [SUB- 12 b, 19.]
A. adj. = SUBTROPICAL.
1891. in Cent. Dict.
1900. B. D. Jackson, Gloss. Bot. Terms, Subtropic, applied to half-hardy plants which in temperate climates can thrive in summer only.
B. sb. pl. Subtropics: the regions adjacent to or bordering on the tropics.
1886. Times (Philad.), 3 May, 3/3 (Cent.). There are but two counties [of Florida] in the sub-tropics—Dade and Monroe.
1898. P. Manson, Trop. Diseases, I. i. 1. The principal cause of morbidity in the tropics and sub-tropics.
