Cornus (genus) in the context of "Bract"

Tupelo /ˈtuːpɪloʊ/, genus Nyssa /ˈnɪsə/, is a small genus of deciduous trees with alternate, simple leaves. It is sometimes included in the subfamily Nyssoideae of the dogwood family, Cornaceae, but is placed by other authorities in the family Nyssaceae. In the APG IV system, it is placed in Nyssaceae.

Most Nyssa species are highly tolerant of wet soils and flooding, and some need such environments as habitat. Some of the species are native to eastern North America, from southeastern Canada through the Eastern United States to Mexico and Central America. Other species are found in eastern and southeastern Asia, from China south through Indochina to Java and southwest to the Himalayas.

The Cornaceae, the dogwood family, are a cosmopolitan family of flowering plants in the order Cornales. The family contains approximately 85 species in two genera, Alangium and Cornus. They are mostly trees and shrubs, which may be deciduous or evergreen, although a few species are perennial herbs. Members of the family usually have opposite or alternate simple leaves, four- or five-parted flowers clustered in inflorescences or pseudanthia, and drupaceous fruits. The family is primarily distributed in northern temperate regions and tropical Asia. In northern temperate areas, Cornaceae are well known from the dogwoods Cornus.

The systematics of Cornaceae has been remarkably unsettled and controversial, and many genera have been added to it and removed from it over time. (One researcher called it a "dustbin".) Molecular phylogenetics have clarified the relatedness of some associated genera, and at least nine genera that were previously included in Cornaceae have been eliminated from the order Cornales entirely, but the circumscription of Cornaceae is still unclear. The Angiosperm Phylogeny Group usually defines Cornaceae as comprising the genera Cornus and Alangium as well as five genera now separated into the family Nyssaceae. However, many of these genera are sometimes split off into their own families (e.g. Alangiaceae), and the usage remains inconsistent.

In forestry and ecology, understory (American English), or understorey (Commonwealth English), also known as underbrush or undergrowth, includes plant life growing beneath the forest canopy without penetrating it to any great extent, but above the forest floor. Only a small percentage of light penetrates the canopy, so understory vegetation is generally shade-tolerant. The understory typically consists of trees stunted through lack of light, other small trees with low light requirements, saplings, shrubs, vines, and undergrowth. Small trees such as holly and dogwood are understory specialists.

In temperate deciduous forests, many understory plants start into growth earlier in the year than the canopy trees, to make use of the greater availability of light at that particular time of year. A gap in the canopy caused by the death of a tree stimulates the potential emergent trees into competitive growth as they grow upward to fill the gap. These trees tend to have straight trunks and few lower branches. At the same time, the bushes, undergrowth, and plant life on the forest floor become denser. The understory experiences greater humidity than the canopy, and the shaded ground does not vary in temperature as much as open ground. This causes a proliferation of ferns, mosses, and fungi and encourages nutrient recycling, which provides favorable habitats for many animals and plants.