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Amanoa, W. John Hayden
Amanoa, W. John Hayden
Biology Faculty Publications
Monoecious or dioecious trees or shrubs, latex absent. Leaves alternate, distichous, evergreen, simple, coriaceous, glabrous; stipules intrapetiolar, paired, or confluent across the leaf axil; margins entire; venation pinnate. Inflorescence axillary and/or terminal, of densely bracteate clusters (reduced cymules), in the axils of ordinary foliage leaves, in nonleafy pseudoterminal aggregates that revert to vegetative growth, or (in neotropical species) in the axils of alternate, reduced, crescentiform stipular bracts of determinate deciduous spiciform axes borne in groups of 1-several per branch apex; axes straight or sinuous; floral bracts minute, deltate, with abaxially pubescent midribs. Staminate flowers sessile or pedicellate, regular; perianth biseriate; …
Seedling Development In Species Of Chamaesyce (Euphorbiaceae) With Erect Growth Habits, W. John Hayden, Olga Troyanskaya
Seedling Development In Species Of Chamaesyce (Euphorbiaceae) With Erect Growth Habits, W. John Hayden, Olga Troyanskaya
Biology Faculty Publications
Seedling development is described for Chamaesyce hirta, C. hypericifolia, and C. mesembrianthemifolia as discerned by light microscopy and scanning electron microscopy. Although these species ultimately develop erect to ascending growth habits, epicotyl development is limited to the production of a single pair ofleaves located immediately superjacent to and decussate with the cotyledons. The shoot system develops from one or more buds located in the axils of the cotyledons. In all respects, seedling ontogeny is very similar to that of previously studied prostrate species of Chamaesyce. Evidence from seedling ontogeny thus contradicts a hypothesis concerning homologies of plant …
Revision Of The Cerrado Hemicryptophytic Chamaesyce Of Boissier's "Pleiadeniae" (Euphorbiaceae), Mark P. Simmons, W. John Hayden
Revision Of The Cerrado Hemicryptophytic Chamaesyce Of Boissier's "Pleiadeniae" (Euphorbiaceae), Mark P. Simmons, W. John Hayden
Biology Faculty Publications
The species of Chamaesyce classified by Boissier as the "Pleiadeniae'" are revised in light of presently available collections. Six species are accepted and new combinations are proposed for C. nana, C. setosa, C. tamanduana, and C. viscoides. Although these herbaceous perennials of cerrado vegetation of Brazil, northern Argentina, and adjacent countries are distinctive ecologically and geographically, cladistic analysis does not support their recognition as a monophyletic group.
Systematic Anatomy Of Euphorbiaceae Subfamily Oldfieldioideae I. Overview, W. John Hayden
Systematic Anatomy Of Euphorbiaceae Subfamily Oldfieldioideae I. Overview, W. John Hayden
Biology Faculty Publications
The biovulate subfamily Oldfieldioideae of Euphorbiaceae, characterized by spiny pollen, is an otherwise apparently diverse assemblage of mostly Southern Hemisphere trees and shrubs that traditionally have been allied with genera of Phyllanthoideae and Porantheroideae sensu Pax and Hoffmann. Although fairly diverse anatomically, the following structures characterize the subfamily with only a few exceptions: pinnate brochidodromous venation with generally randomly organized tertiary and higher order venation; foliar and petiolar glands absent; unicellular or unbranched uniseriate trichomes; latex absent; mucilaginous epidermis or hypodermis; brachyparacytic stomata; vessel elements with simple perforation plates and alternate, often very small, intervascular pits; thick-walled nonseptate imperforate tracheary …
Notes On Neotropical Amanoa (Euphorbiaceae), W. John Hayden
Notes On Neotropical Amanoa (Euphorbiaceae), W. John Hayden
Biology Faculty Publications
Lectotypes are designated for Amanoa caribaea Krug & Urban and A. guianensis Aublet; presumed syntypes of the latter taxon are shown to be heterogeneous by inclusion of a previously unrecognized species. Four new species of Amanoa are described: A. congesta from French Guiana and northeastern Brazil; A. gracillima from Manaus, Brazil; A. nanayensis from Amazonian Peru and adjacent Colombia and Brazil; and A. neglecta from French Guiana and Surinam. Amanoa sinuosa is proposed as a new name for the later homonym A. robusta Leal. A key to the 13 neotropical species is presented.
Eryngium Prostratum In Central Virginia, W. John Hayden
Eryngium Prostratum In Central Virginia, W. John Hayden
Biology Faculty Publications
While visiting Pocahontas State Park in Chesterfield County, Virginia during the fall of 1984, an unfamiliar blue-flowered plant was observed growing near the upper reaches of Swift Creek Lake. This proved to be Eryngium prostratum Nuttall ex DC., a species common near bodies of water in the southeast U.S. While several standard floras include Virginia in the distribution of this plant (Fernald 1950, Gleason 1952, Gleason & Cronquist 1963, Radford et al 1968, Godfrey & Wooten 1981), the only counties for which it is recorded in Harvill et al (1981) are along the extreme southern border of the state, i.e., …
Wood Anatomy And Relationships Of Neowawraea (Euphorbiaceae), W. John Hayden, Dorthe S. Brandt
Wood Anatomy And Relationships Of Neowawraea (Euphorbiaceae), W. John Hayden, Dorthe S. Brandt
Biology Faculty Publications
Wood anatomy of three specimens of Neowawraea phyllanthoides Rock, a rare and endangered member of Euphorbiaceae endemic to the Hawaiian Islands, is described and compared with woods of other genera of subfamily Phyllanthoideae. Neowawraea has often been associated or synonymized with Drypetes Vahl. Wood of Neowawraea is diffuse porous, perforation plates are simple, imperforate tracheary elements are thin-walled septate fiber-tracheids, rays are heterocellular and crystalliferous, and axial xylem parenchyma is restricted to a few scanty paratracheal and terminal cells. In several respects these results differ from earlier published descriptions of the wood of this taxon; these earlier descriptions are shown …
Comparative Anatomy And Systematics Of Picrodendron, Genus Incertae Sedis, W. John Hayden
Comparative Anatomy And Systematics Of Picrodendron, Genus Incertae Sedis, W. John Hayden
Biology Faculty Publications
This study of the vegetative anatomy of Picrodendron and some of its putative relatives has been undertaken in order better to understand its natural relationships. Despite the number of anatomical studies in the literature (Jadin, 1901; Solereder, 1908; Boas, 1913; Webber, 1936; Heimsch, 1942; Record & Hess, 1943; Metcalfe & Chalk, 1950), our information on the anatomy of Picrodendron is still incomplete· for example, nodal and petiolar anatomy has apparently never been described. Furthermore, with the exception of Record and Hess (1943), who discussed Picrodendron in a family by itself, other anatomists have compared Picrodendron only with members of Simaroubaceae, …