The labiates of the Malay Peninsula
This short note by H. N. Ridley reviews the Labiates (Lamiaceae) recorded in the Materials for a Flora of the Malay Peninsula, assessing which of the thirty species listed by Dr. Prain are truly indigenous to the region.
Summary
Ridley argues that the Labiates are poorly represented in the rain forest because they are small, open-country plants whose seeds are dispersed only by wind, making them unable to establish in dense shade. The sole exception is Gomphostemma, whose fruits have evolved into pulpy drupes dispersed by birds—analogous to Hedyotis congesta among the Rubiaceae (p. 105).
Of the thirty species in the Materials, Ridley classifies most as garden escapes or introductions (e.g., Ocimum species, Mentha javanica, Salvia coccinea, Leonurus sibiricus, Anisomeles malabarica), while noting that the two American Hyptis species are thoroughly established throughout the tropics. He identifies a small group of true indigenous weeds of cleared ground (Coleus atropurpureus, Anisomeles ovata, Leucas zeylanica, L. lavandulifolia, Calamintha gracilis) and discusses Pogostemon Heyneanus in some detail, noting its collection from forest stream banks and its use in Malay medicine (p. 106–107). He concludes that only fifteen species can be considered truly indigenous to the Malay Peninsula (p. 107).