44 research outputs found
Comparative vegetative anatomy and systematics of Oncidiinae (Maxillarieae, Orchidaceae)
Get PDFSubtribe Oncidiinae comprises a vegetatively heterogeneous assemblage of species that has persistently been incapable of organization. Anatomy was considered to be a possible means to resolve the perplexity of relationships amongst the constituent taxa. The consistent occurrence of a foliar hypodermis, homogeneous mesophyll, conical silica bodies in stegmata, and ubiquitous fibre bundles in leaves provides a matrix for linking the taxa, as do the parenchymatous pith and O-thickened endodermal cell walls in roots. However, the strict consensus of the 40 genera studied was completely unresolved, suggesting that vegetative characters alone are insufficient to assess the relationships amongst these taxa, a conclusion also reached for the remainder of Maxillarieae
Comparative vegetative anatomy and systematics of Oncidiinae (Maxillarieae, Orchidaceae)
Get PDFSubtribe Oncidiinae comprises a vegetatively heterogeneous assemblage of species that has persistently been incapable of organization. Anatomy was considered to be a possible means to resolve the perplexity of relationships amongst the constituent taxa. The consistent occurrence of a foliar hypodermis, homogeneous mesophyll, conical silica bodies in stegmata, and ubiquitous fibre bundles in leaves provides a matrix for linking the taxa, as do the parenchymatous pith and O-thickened endodermal cell walls in roots. However, the strict consensus of the 40 genera studied was completely unresolved, suggesting that vegetative characters alone are insufficient to assess the relationships amongst these taxa, a conclusion also reached for the remainder of Maxillarieae
Vegetative anatomy and systematics of Triphorinae (Orchidaceae)
Get PDFTriphorinae represents a group of three anatomically simple genera, the structural features of which are unspecialized. The anomocytic stomatal pattern occurs in all genera; it predominates in Triphora . A foliar hypodermis, sclerenchyma, fibre bundles and stegmata are absent. The mesophyll is homogeneous. The exodermal and endodermal cells in the roots are entirely thin-walled and tilosomes are absent. However, there are anatomical modifications that appear to be unique: root hairs in Monophyllorchis are borne on velamenal buttresses and, in Psilochilus , they arise endogenously. In the root vascular system of Psilochilus , the metaxylem occurs as a circumferential band. The surfaces of stems in Triphora are tuberculate. Mycorrhizae appear to characterize the root cortices of all genera
Comparative vegetative anatomy and systematics of Laeliinae (Orchidaceae)
Get PDFLaeliinae are one of the most prominent orchid subtribes, with c. 40 genera and nearly 1500 species, and contain a disparate group of taxa with widely varying morphological features. There does not appear to be a complex of characters to which one can refer in order to delineate the subtribe as a whole. Thus, it was thought that vegetative anatomy might provide clues to the monophyly of the group. The microscopic structure of the leaves, stems and roots of representatives of most of the genera was studied. It was concluded that the anatomy lacks overall uniformity and that vegetative characters alone are insufficient to assess the relationships amongst the genera. The only nearly consistent anatomical feature was the abaxial row of fibre bundles in the leaves. Thus, anatomically, as well as morphologically, Laeliinae are a mixed bag
The Impact of Cervid Herbivory on Industrial Fiber Hemp in East Central Illinois
Get PDFThe last several years have seen large increases in white-tailed deer populations across the United States. Many studies have analyzed the effects that white-tailed deer have on different ecosystems. However, little to no studies have analyzed the effects of white-tailed deer on the production of industrial hemp fiber. In this study, we examined two different varieties of hemp fiber crops, and the impact white-tailed deer may have on their production. Our study was conducted in a flat test plot with surrounding woods and known white-tailed deer traffic in central Illinois, using two (6 × 6 m) plots that were adjacent to each other. One plot had fencing around it to prevent white-tailed deer from accessing the crop, while the adjacent control plot was left open. We observed a much greater height and mass in the northern planted seeds for both the open (control) and enclosed (exclosure) plots compared to the southern plots\u27 height and mass. We also observed the growth of more invasive plants in the exclosure when compared to the control plot
