| Status |
| Description |
| Life History |
| Habitat |
| Distribution |
| Field Characters |
| Causes of Decline |
| Recovery Needs |
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Cuscuta attenuata
Waterfall's tapertip dodder
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Status Recent survey work indicates this species has a larger range than originally thought. However, additional field surveys are needed to determine current population trends. Previously, the species was a Category 2 (58 FR 188; September 30, 1993), but currently has no Federal status.
Life History
Waterfall’s tapertip dodder parasitizes sumpweed (Iva annua) almost exclusively. One record does exist of it parasitizing Aster species. The seeds of Waterfall's tapertip dodder germinate in May. Plants flower in late summer.
Habitat
The host plant, sumpweed, establishes large populations on mudflats, floodplains, and disturbed areas. Sumpweed is found throughout the eastern one-half of the United States.
Distribution
Waterfall's tapertip dodder is known only from four locations in Oklahoma (one each in McCurtain, Beckham, Cleveland, and Comanche counties). There are five known sites in Texas, and one in Kansas.
Field Characters
Dodder species cannot be identified until mature flowers develop. There are 10 species of dodder in Oklahoma, but Waterfall's tapertip dodder can be distinguished from the others by its short pedicels, tapering calyx lobes, and globular fruits.
Causes of Decline
Waterfall’s tapertip dodder is highly susceptible to land use changes. Alteration of sites could easily eliminate populations. Potential threats include channelization of streams, herbicides, and conversion of land to pasture. At the present time, land management at the site where this species was discovered has resulted in persistence of the population.
Recovery Needs
Populations of Waterfall’s tapertip dodder can persist at sites suitable for sumpweed. If populations of the host plant are maintained, Waterfall’s tapertip dodder will be partially protected.
Description
Waterfall’s tapertip dodder is a parasitic, herbaceous annual. They are leafless and do not have roots anchoring them into the ground. Instead, a padlike modified root (= haustorium) penetrates the tissue of the host plant. Stems are yellowish-orange wrapping and looping between hosts plants. The resulting appearance resembles a tangled mass of twine. Inflorescences are dense clusters of flowers. Flowers are small, white and borne on short pedicels (= stalk of a single flower) are about 1/16 inch (0.5-2.0 mm) long. Calyx is formed of five fused sepals with slender tapering lobes and is approximately 1/32 inch (1 mm) long. Corollas consist of five petals which are also fused. Petal lobes taper and curl outward. Petals are less than 1/16 inch (3 mm) long. There are five stamens which extend out of the flower above the petals. The pistil is composed of two separate styles arising from a spherical two celled ovary. Fruits are globular, yellow-brown capsules that open irregularly. Seed are small, brown, and hairless.