Commemorating Prof.William Carpenter 1811–48 a botanist from Louisiana.
For description see the only species in the genus.
Stamens more than twice as many as petals; flower parts 5-7.
1 genus with 1 species from the Sierra Nevada, California.
Source: (2002). Hydrangeaceae. In: . Horticultural Flora of South-eastern Australia. Volume 3. Flowering plants. Dicotyledons. Part 2. The identification of garden and cultivated plants. University of New South Wales Press.