Harperella Rose and Tiedemannia DC. (Apiaceae)

In North Carolina, three genera of Apiaceae exhibit transversely septate leaves: Harperella, Lilaeopsis, and Tiedemannia. Lilaeopsis can be easily distinguished from the other two by its prostrate habit. A key to distinguish between the rachis-leaved species of Harperella and Tiedemannia is provided below.

Federally listed taxa—

Harperella nodosa
(Fed E, State E | S1 G2)

Habitat. Rocky shoals of clear, swift-moving streams.

Range. Endemic to the southeastern United States.

Additional resources. NHP | Recovery plan

Notes. Listed as Ptilimnium nodosum s.l., which is a broad concept that includes P. nodosum s.s. (upland depression ponds and seepages; GA, SC), P. viviparum (rocky shoals; NC, VA, MD, WV), and P. fluviatile (AL, AR); see Weakley (2010) for a key. Whether this complex should be treated as one broad species or three separate species has been a subject of debate. Kress et al. (1994) provide an overview of this debate and genetic evidence supporting recognition of three separate species. More recent work argues for the recognition of a single species (Feist et al. 2012).

 Tiedemannia canbyi
(Fed E, State E | S1 G2)

Habitat. Clay-based Carolina bays and depressional wetlands.

Range. Endemic to the southeastern United States.

Additional resources. NHP | Recovery plan

Notes. Listed as Oxypolis canbyi.

Key to rachis-leaved species of Harperella and Tiedemannia in North Carolina

Key adapted from Weakley (2008). Photos by Krings, unless otherwise indicated. Line drawings from Britton & Brown (1913). Maps courtesy of USDA PLANTS and the North Carolina Natural Heritage Program.

1. Mericarps subterete in cross-section (i.e., semi-circular) [Harperella]...H. nodosa*

1’. Mericarps lenticular in cross-section (i.e., dorsally flattened) [Tiedemannia]...2.

2. Mature fruits with corky-thickened peripheral ribs, the fruit with a narrowly rectangular cross-section, about as thick near the ends of the ribs as at the center, 0.8–2 mm thick at the edge; plants with stoloniferous rhizomes 1–3 (–10) dm long; lower nodes often losing their leaves by flowering; umbellets/umbel 5–9 (–12)...T. canbyi*

2’. Mature fruits with peripheral ribs progressively thinning away from the seed cavity, the fruit with a fusiform cross-section, thinner toward the ends of the ribs than at the center, 0.2 mm thick at the edge; plants with stout rhizomes or a caudex, not long stoloniferous; lower nodes generally retaining their leaves until flowering; umbellets/umbel 10–20...T. filiformis