Alexander Krings

On the Generic Circumscription of Gonolobus (Apocynaceae, Asclepiadoideae): Evidence from Molecules and Morphology

Abstract Gonolobus (Apocynaceae, Asclepiadoideae) is a New World genus comprising an estimated 100–150 species. Variation in estimated species numbers is largely the result of still poorly known tropical taxa and differences regarding generic limits. Characters historically used to delimit genera such as Gonolobus within Gonolobinae—such as laminar dorsal anther appendages and various follicle morphologies—have been controversial and their evolution remains unknown, not having been explored in a phylogenetic framework. The primary objectives of the current study were to (1) test the monophyly of Gonolobus sensu Woodson in the context of a phylogeny of New World Asclepiadeae and (2) explore the evolution of laminar dorsal anther appendages and winged follicles with respect to their potential utility in generic circumscription. Chloroplast (trnL–F, rpsl6) data are newly presented for sixty-three taxa of Gonolobinae, representing an increased sampling of the subtribe from a maximum of seven taxa in prior studies. These data were combined with a previously published dataset to form a 183 taxa matrix of New World Asclepiadeae. Nuclear (LEAFY) data were newly generated for forty-nine taxa of Gonolobinae. Evidence from parsimony and Bayesian analyses of chloroplast and nuclear data presented here supports the monophyly of both the subtribe and the genus Gonolobus in a narrow or broad sense. Laminar dorsal anther appendages are restricted to Gonolobus s.l. or s.s., although parsimony remains equivocal on whether they evolved once or twice. A transversion in the trnL–F spacer is shown synapomorphic for Gonolobus s.s. Two indels in LEAFY, as well as winged follicles, are shown synapomorphic for Gonolobus s.l.

Environmental Controls of Reproduction and Early Growth of Lindera melissifolia (Lauraceae)

ABSTRACT Lindera melissifolia is a federally endangered endemic shrub of the southeastern United States. Numerous populations are gender-biased. The goal of this study was to determine environmental conditions most appropriate for establishment and growth of seedlings and adult females. Seedlings were grown under varied moisture and light to compare growth rates and morphological ratios. Seedlings were clipped to simulate two levels of disturbance, and their shoot sprouting ability was assessed. Densities of adult flowering stems, co-occurring species, and solar transmittance were analyzed within two North Carolina populations. The lowest levels of light resulted in decreased growth, but light and moisture did not interact to affect seedling growth rate significantly. Morphological ratios and growth responses followed patterns expected for plants exhibiting plasticity in response to varied light levels, but not to moisture. Clipping immature plants below root collars decreased survivorship to 31%. Growth rates of new shoots when clipped below and above the root collar were 40% and 58% percent lower, respectively (p < 0.001). Percent cover of Lindera melissifolia explained 52% of the variation in the number of male flowering stems per plot and 14% of the variation in female stems per plot. No relation of stem density to percent transmittance was found. Indicator species analysis revealed association of males with facultative wetland species and a weak association of females with wetland obligates, but overall difference in vegetation composition between plots with or without females present was slight (MRPP: A = 0.02, p = 0.016). We concluded hydrology should be a primary concern for future studies.

On the Identity of the Weedy Bittercresses (Cardamine : Brassicaceae) in United States Nurseries: Evidence from Molecules and Morphology

Bittercress (Brassicaceae) is one of the most prolific and costly weeds of the container nursery industry. Bittercress accessions from container nurseries throughout the major production zones in the United States were examined and compared with herbarium specimens. The identity of these weedy bittercress species were further explored using sequences of the nuclear ribosomal DNA (nrDNA) internal transcribed spacer (ITS) region and the nrDNA region for the COP1-interacting protein 7 (CIP7). Four species of bittercress were detected in the nursery industry of the United States, including New Zealand bittercress, hairy bittercress, flexuous bittercress, and little bittercress. The taxon referred to here as Cardamine flexuosa With. (flexuous bittercress) likely contains two genotypes previously reported as European C. flexuosa and Asian C. flexuosa. Phylogenetic relationships between the four species we examined, particularly in relationship to flexuous bittercress, were not fully resolved by the molecular evidence generated for this study. New Zealand bittercress is nonnative and does not appear in current keys to the species for the United States. Flexuous bittercress is also an alien species, which appears in some U.S. keys but not in all. To aid nurserymen and botanists in identification of these four closely related bittercress species, a key was developed and is accompanied by detailed descriptions and illustrations. Nomenclature Flexuous bittercress, Cardamine flexuosa With. CARFL; hairy bittercress, Cardamine hirsuta L. CARHI; Japanese bittercress, Cardamine scutata Thunb. CARSC; little bittercress, Cardamine oligosperma Nutt. CAROL; New Zealand bittercress, Cardamine corymbosa Hook f.

Two New Species and Three Lectotypifications in the Ibatia-Matelea Complex (Apocynaceae: Asclepiadoideae) from Northern South America

Abstract Two new species of Matelea (Apocynaceae: Asclepiadoideae, Gonolobinae) are described from northern South America: M. fontana and M. pacifica. The species belong to the Ibatia-Matelea complex, but exhibit distinct differences in floral characters from previously known taxa, including the structure of gynostegial coronas. A key and descriptions to members of the northern South American and West Indian Ibatia-Matelea complex is provided, including M. cumanensis, M. maritima, and M. rubra. Asclepias maritima, Cynanchum fimbriatum, and Ibatia muricata are lectotypified.

Novelties in Gonolobus (Apocynaceae: Asclepiadoideae) from the Lesser Antilles

Abstract Five new species of Gonolobus (Apocynaceae: Asclepiadoideae) are described from the Lesser Antilles: G. absalonensis, G. dussii, G. iyanolensis, G. waitukubuliensis, and G. youroumaynensis. The species exhibit distinct differences in floral characters, including the structure of corolline and gynostegial coronas. Gonolobus martinicensis is lectotypified. A key to Gonolobus in the Lesser Antilles is provided.

A New Species in the Matelea palustris Complex (Apocynaceae, Asclepiadeae) and a Synopsis of the Complex in the Guianas and Northern Brazil

Abstract— A new, non-climbing species from the Guiana Shield is described and illustrated: Matelea graciliflora (Apocynaceae, Asclepiadeae, Gonolobinae). The new species is morphologically similar to M. herbacea and M. palustris (together the only other erect species of Gonolobinae in the Guianas), but can be differentiated by a number of characters, including perianth and corona dimensions and corolla color. A synopsis of the erect members of the Matelea palustris complex in the Guianas and northern Brazil is provided.

Vegetative Impact of Feral Horses, Feral Pigs, and White-tailed Deer on the Currituck National Wildlife Refuge, North Carolina

ABSTRACT  The Currituck National Wildlife Refuge (CNWR) in North Carolina is inhabited by feral horses (Equus caballus), feral pigs (Sus scrofa), and white-tailed deer (Odocoileus virginianus). The impact of these species on the vegetation of CNWR is unknown. To assess impact, we created two replicate exclosure plots within maritime forests, brackish marshes, and maritime grasslands. An electric fence divided each habitat into two sections: including or excluding horses. On each side of the electric fence within each habitat, we sampled three different 5 × 5 m plots (i.e., 36 plots). The first was a fenced exclosure 3 m high, the second a fenced exclosure raised 1 m above the ground and extended to 3 m, and the third, a control, was not fenced. Within plots, we created two 1 m transects, and randomly selected and tagged grasses, forbs, shrubs, and trees. We measured the distances from base to tip of herbs and from branching point to terminal bud in shrubs. We used a linear model to analyze plant growth rate. We used a length ratio adjusted by the number of days as the response variable. Out of 1,105 tagged plants, we detected 87 disturbances; 80 where horses were present and 7 where horses were excluded. Overall, horses were responsible for 84% of disturbances. Most disturbances occurred in brackish marshes on Schoenoplectus pungens. We detected a significant effect of exclosure treatment on plant growth rate where horses were present (p = 0.035), but not where they were excluded (p = 0.32).

Gonolobus aloiensis (Apocynaceae, Asclepiadoideae), a New Species from St. Eustatius

Abstract A new species from St. Eustatius, Gonolobus aloiensis (Apocynaceae, Asclepiadoideae, Gonolobinae), is described and illustrated. This new species is endemic to St. Eustatius (northern Leeward Islands) and represents the first record of the genus for the island. It exhibits morphological similarity to continental G. albomarginatus, but can be distinguished in part by abaxial leaf surfaces glabrous, calyx and corolla lobes shorter and narrower, and abaxial corolla lobes completely lacking glandular indumentum and with eglandular indumentum restricted at most to only the top two-thirds of the lobes. An amplified key to species of Gonolobus s. s. in the West Indies is provided.

A new species and a new combination in Phaeostemma (Apocynaceae, Asclepiadoideae, Gonolobinae).

Abstract Phaeostemma surinamensis Morillo & Krings, sp. nov., anew species of Apocynaceae (Asclepiadoideae, Gonolobinae) is described and illustrated, and the new combination Phaeostemma fucata (Woodson) Morillo & Krings, comb. nov., is made. The new species, known only from a lowland wet forest of Suriname, seems to be closely related to Phaeostemma fucata, which is an endemic to Ptari-tepui, a sandstone mountain in the southeastern edge of the Venezuelan Guayana.

Matelea s. l. (Apocynaceae, Asclepiadoideae) in the West Indies

Abstract The last treatment of Gonolobinae (Apocynaceae, Asclepiadoideae) in the West Indies is over a hundred years old and a number of new species have been described since. Although Fischeria and Gonolobus s. s. were revised recently, a complementary, comprehensive, recent regional treatment of Matelea s. l. is lacking. Considering the rarity of taxa of Matelea s. l. in the West Indies, thirty-three of thirty-six taxa are endemic to a single island each, and that nearly half of the known species have been described since Schlechters treatment of 1899, the objective of the present study is to provide a synopsis of the genus in the area to facilitate field recognition and future collections. The treatment is based on critical study of ca. 250 specimens of the fifty-some known species in Caribbean Gonolobinae, fieldwork in the region, and molecular analyses. In addition to a comprehensive key and descriptions, illustrations of the complex gynostegial coronas are provided here for the first time for numerous taxa. A new combination is made in Matelea for Gonolobus haitiensis: Matelea haitiensis.