Harperella
in North CarolinaPtilimnium nodosum
STATUS: Endangered
DESCRIPTION: This annual herb grows to a height of 0.15 to 1.0 meter
(6 to 36 inches). The leaves are reduced to hollow, quill-like structures.
The small, white flowers occur in heads, or umbels, not unlike those of
Queen Anne's lace (Daucus carota). Flowers have five regular parts
and are bisexual or unisexual, each umbel containing both perfect and male
florets. Seeds are elliptical and laterally compressed, measuring 1.5 to
2.0 millimeters (mm) in length (Kral 1980, 1981). In pond habitats, flowering
begins in May, while riverine populations flower much later, beginning
in late June or July and continuing until frost. Pollination biology of
the species has not been studied, but seed set is apparently profuse in
this annual since populations in localized areas can achieve a high density
and number of individuals each year.
RANGE AND POPULATION LEVEL: Harperella is known from 12 extant populations
rangewide. One population occurs in each of two North Carolina counties:
Granville and Chatham. This plant is a relatively prolific annual, and
large numbers may occur within each population, especially along rivers.
HABITAT: Harperella typically occurs in two habitat types: (1) rocky or gravel shoals and margins of clear, swift-flowing stream sections; and (2) edges of intermittent pineland ponds in the coastal plain.
Species Distribution from known occurrences. Species may occur in similar habitats in other counties.Green counties indicate observed within 20 years. Yellow counties indicate an obscure data reference to the species in the county. Red counties indicate observed more than 20 years ago.
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