Commemorating Prof.William Carpenter 1811–48 a botanist from Louisiana.

For description see the only species in the genus.

Softwood cuttings.

Stamens more than twice as many as petals; flower parts 5-7.

1 genus with 1 species from the Sierra Nevada, California.

Source: Spencer, R. (2002). Hydrangeaceae. In: Spencer, R.. 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.