Aureolaria pedicularia

Aureolaria pedicularia
Photo by Catherine Herms, The Ohio State University, Bugwood.org
Scientific classification
Kingdom:	Plantae
Division:	Magnoliophyta - Flowering plants
Class:	Magnoliopsida - Dicotyledons
Order:	Lamiales
Family:	Orobanchaceae
Genus:	Aureolaria
Species:	A. pedicularia
Binomial name
Aureolaria pedicularia ((L.) Raf.
Natural range of Aureolaria pedicularia from USDA NRCS Plants Database.

Common Name: Fernleaf Yellow False Foxglove

Taxonomic notes

Synonyms: Aureolaria pedicularia var. pedicularia; A. pedicularia var. austromontana Pennell; A. pedicularia var. intercedens Pennell; Gerardia pedicularia Linnaeus var. pedicularia; Gerardia pedicularia Linnaeus var. austromontana (Pennell) Fernald; Gerardia pedicularia Linnaeus var. intercedens (Pennell) Fernald; A. pedicularia ssp. caesariensis Pennell; A. pedicularia ssp. carolinensis Pennell; A. pedicularia ssp. austromontana (Pennell) Pennell; A. pedicularia ssp. intercedens (Pennell) Pennell

Description

In its northern range, A. pedicularia is a biennial plant that forms a basal rosette of leaves in late summer and bolts the following spring, while in the southern range, it is an annual (Musselman and Man 1978; Musselman et al. 1969). The stem is terete and covered with glandular hairs . The leaves are fernlike, opposite and sessil .

In the genus Aureolaria, the plants are either annual or perennial. They are parasitic on the roots of Quercus (oaks) and they turn black when dried. The cauline leaves are opposite or subopposite. The flowers are showy, the calyx is 5-parted, the lobes are shorter to longer than the tube. The corolla is yellow in color, bilabiate, and 5-parted. The tube is campanulate and the lobes are spreading. There are 4 stamens, didynamous, included, filaments are flattened, and the 2 longer more or less lanose. The anther sacs are basally awned. The stigma is capitate and exserted. (Radford 1964).

Specifically for A. pedicularia, is an annual, growing up to a 1 m tall, is profusely branched and is pubescent. The stems are glandular-pubescent below, they are not glandular above. They are parasitic to Quercus velutina (black oaks). The basal rosette leaves are elliptic-lanceolate to rhombic, are entire or irregularly crenate-serrate, and approximately 4-8 cm long, 1.5-3 cm wide. The cauline leaves are lanceolate, entire or bipinnately lobed to parted, the divisions are angulate and sometimes serrate puberulent to pubescent, the trichomes are not glandular, and grow to approximately 2-6 cm long, 8-21 cm wide. The flowers are axillary and solitary. The pedicels are 8-16 mm long, the pedicels and calyx tubes are glandular-pubescent. The calyx lobes are usually folios, the calyx lobes are longer than the tube. The corolla is 3-4.5 cm long and 3-4 cm broad. The capsule is ellipsoid and 8-10 mm long; the lower half is enclosed in the calyx tube. The seeds are wingless. Flowers from September to October. (Radford 1964).

Ecology

Habitat

A. pedicularia can occur in slash pinelands, oak-hickory forests, and oak-pine forests (FSU Herbarium; Stiles 1977; Werth et al. 1979). Large populations have been observed on road banks, powerline corridors and other disturbed areas. The inclination for disturbed areas and prolific seed production allows a strong potential as a forest plantation pathogen (Musselman and Mann 1978). Associated species include Pinus rigida, Castanea pumila, Pinus palustris and species of Quercus (Werth and Riopel 1979).

It is a hemiparasitic plant, with a strong affinity for oaks (Musselman and Grelen 1979). Musselman et al. (1969) suggested that A. pedicularia was specific to oak species, however studies have shown populations growing without oaks hosts (Musselman and Grelen 1979; Werth and Riopel 1979). Werth and Riopel (1979) suggest that it does not exhibit a promiscuous parasitism characteristic, but a selectivity for fagaceous roots.

Phenology

Blooms August through September with yellow, zygomorphic campanulate flowers that last one day (Stiles 1977).

Seed bank and germination

The germination of A. pedicularia is epigeal, with the radicle having a strong geotropic response (Musselman et al. 1969). The radicles are covered with root hairs however, seedlings do not have root hairs, this phenomenon could be the result of vestigial characteristics (Musselman et al. 1969). Germination does not depend on light (Musselman et al. 1969).

Fire ecology

It thrives well in fire prone communities and needs periodic fire . Large stands of A. pedicularia have been observed in an oak-pine forest that is burned every third year (Stiles 1977).

Pollination

Three types of bumblebees are responsible for pollination: Bombus impatiens, B. vagans and B. affinis. B. affinis is a nectar robber, cutting holes in the base of the corolla tubes to obtain nectar (Stiles 1977).

Use by animals

Larva of the Orange Sallow moth (Pyrrhia aurantiago) feed on the flower, developing seeds and foliage in early October.

References and notes

Canne, Judith M.. Seed Surface Features in Aureolaria, Brachystigma, Tomanthera, and Certain South American Agalinis (scrophulariaceae). Systematic Botany 5.3 (1980): 241–252

Florida State University Robert K. Godfrey Herbarium database. URL: http://herbarium.bio.fsu.edu. Last accessed: October 2015. Collectors: Robert K. Godfrey. States and Counties: Florida: Wakulla. Compiled by Tall Timbers Research Station and Land Conservancy.

Leicht-Young, S. A., N. B. Pavlovic, et al. (2009). "A comparison of seed banks across a sand dune successional gradient at Lake Michigan dunes (Indiana, USA)." Plant Ecology 202: 299-308.

Musselman, L. J. (1969). "Observations on the life history of Aureolaria grandiflora and Aureolaria pedicularia (Scrophulariaceae)." American Midland Naturalist 82: 307-311.

Musselman, L. J. and H. E. Grelen (1979). "POPULATION OF AUREOLARIA-PEDICULARIA (L) RAF (SCROPHULARIACEAE) WITHOUT OAKS." American Midland Naturalist 102(1): 175-177.

Musselman, L. J. and W. F. Mann, Jr (1978). Root parasites of southern forests. , USDA Forest Service, Southern For. Exp. Station, New Orleans, LA. Gen. Tech. Rpt. SO-20. : 76.

Radford, Albert E., Harry E. Ahles, and C. Ritchie Bell. Manual of the Vascular Flora of the Carolinas. 1964, 1968. The University of North Carolina Press. 956-7. Print.

Stiles, Edmund W.. Foraging Behavior of Bumblebees on False Foxglove. Journal of the New York Entomological Society 85.4 (1977): 249–252.

Werth, Charles R., and James L. Riopel. A Study of the Host Range of Aureolaria Pedicularia (L.) Raf. (Scrophulariaceae). American Midland Naturalist 102.2 (1979): 300–306.