Heuchera parviflora

The Heuchera parviflora complex is remarkable for the very narrow habitat requirements its members display. The typical habitat is a sandstone rockhouse, a shallow cave or undercut in sandstone; these are common in certain areas of the eastern U.S.

Recently I have worked on realigning species boundaries using morphology and DNA evidence (Taxon, 2015). I have followed the new taxonomic recommendations in this webpage. Heuchera parviflora is taken here as comprising only those populations east of the Ozarks with long petiole hairs, styles, and stamens. For the other members, see H. missouriensis, and H. puberula.

Much of the seed morphological variation in the genus occurs in this subsection (Villosae), but within the H. parviflora group seeds are highly variable and I have not found them useful.

The similarity of the name of this species to H. parvifolia has caused endless confusion in the literature and herbaria. Any references to a plant by this name in the western U.S. should be taken to mean H. parvifolia.

H. parviflora var. parviflora

This is the typical plant of rockhouses in the Cumberland Plateau. In certain areas, such as better parts of the Daniel Boone National Forest, it can be very common and even a roadside plant. It also occurs as a disjunct in certain areas of the southern Blue Ridge escarpment, although it is more difficult to find there. The floral close-ups come from the Kentucky and Tennessee Cumberland; the lower two come from southern Ohio.

H. parviflora var. saurensis.

This variety occurs in the Sauratown Mountains, and one adjacent station closer to the Blue Ridge. All occurrences are in quartzitic regions. These pictures come from Table Rock Mountain (top right) and Pilot Mountain (others).