From The Collaborative International Dictionary of English v.0.48 :
Sweetbrier \Sweet"bri`er\, n. (Bot.) A kind of rose ({Rosa rubiginosa) with minutely glandular and fragrant foliage. The small-flowered sweetbrier is Rosa micrantha. [1913 Webster]From WordNet (r) 3.0 (2006) :
sweetbrier n 1: Eurasian rose with prickly stems and fragrant leaves and bright pink flowers followed by scarlet hips [syn: sweetbrier, sweetbriar, brier, briar, eglantine, Rosa eglanteria]