(Vol. 09, 2006-12) Species Of Philadelphus (Hydrangeaceae) From Trans-Pecos Texas

Three species of Philadelphus are accepted as occurring in Trans-Pecos, Texas: P. mearnsii, P. microphyllus, and P. serpyllifolius. Philadelphus mearnsii is known only from Culberson and El Paso counties; P. microphyllus and P. serpyllifolius are more widespread. Philadelphus microphyllus is treated as having three intergrading varieties: Philadelphus microphyllus var. argenteus, P. m. var. crinitus (C. L. Hitchc.) B. L. Turner, and P. m. var. microphyllus. Philadelphus serpyllifolius is treated as having two intergrading varieties: Philadelphus serpyllifolius var. intermedius B.L. Turner, and P. s. var. serpyllifolius. Maps showing their distributions in the area concerned are provided.