Herbaceous plants are vascular plants that have no persistent woody stems above ground. [1] [2] This broad category of plants includes many perennials, and nearly all annuals and biennials. [3]
Herbaceous plants are vascular plants that have no persistent woody stems above ground. [1] [2] This broad category of plants includes many perennials, and nearly all annuals and biennials. [3]
The fourth edition of the Shorter Oxford English Dictionary defines "herb" as:
The same dictionary defines "herbaceous" as:
Botanical sources differ from each other on the definition of "herb". For instance, the Hunt Institute for Botanical Documentation includes the condition "when persisting over more than one growing season, the parts of the shoot dying back seasonally". [5] Some orchids, such as species of Phalaenopsis , are described in some sources (including the authoritative Plants of the World Online) as "herbs" but with "leaves persistent or sometimes deciduous". [6] [7] In the glossary of Flora of the Sydney Region, Roger Charles Carolin defines "herb" as a "plant that does not produce a woody stem", and the adjective "herbaceous" as meaning "herb-like, referring to parts of the plant that are green and soft in texture". [8] [9]
Herbaceous plants include graminoids, forbs, and ferns. [10] Forbs are generally defined as herbaceous broad-leafed plants, [11] while graminoids are plants with grass-like appearance including true grasses, sedges, and rushes. [12] [13]
Herbaceous plants most often are low-growing plants, different from woody plants like trees and shrubs, tending to have soft green stems that lack lignification and their above-ground growth is ephemeral and often seasonal in duration. [14] By contrast, non-herbaceous vascular plants are woody plants that have stems above ground that remain alive, even during any dormant season, and grow shoots the next year from the above-ground parts – these include trees, shrubs, vines and woody bamboos. Banana plants are also regarded as herbaceous plants because the stem does not contain true woody tissue. [15]
Some herbaceous plants can grow rather large, such as the genus Musa , to which the banana belongs. [16]
Some relatively fast-growing herbaceous plants (especially annuals) are pioneers, or early-successional species. Others form the main vegetation of many stable habitats, occurring for example in the ground layer of forests, or in naturally open habitats such as meadow, salt marsh or desert. Some habitats, like grasslands and prairies and savannas, [17] are dominated by herbaceous plants along with aquatic environments like ponds, streams and lakes.
The age of some herbaceous perennial plants can be determined by herbchronology, the analysis of annual growth rings in the secondary root xylem. [18]
Herbaceous plants do not produce perennializing above-ground structures using lignin, which is a complex phenolic polymer deposited in the secondary cell wall of all vascular plants. The development of lignin during vascular plant evolution provided mechanical strength, rigidity, and hydrophobicity to secondary cell walls creating a woody stem, allowing plants to grow tall and transport water and nutrients over longer distances within the plant body. Since most woody plants are perennials with a longer life cycle because it takes more time and more resources (nutrients and water) to produce persistently living lignified woody stems, they are not as able to colonize open and dry ground as rapidly as herbs.[ citation needed ]
The surface of herbs is a catalyst for dew, [19] [20] which in arid climates and seasons is the main type of precipitation and is necessary for the survival of vegetation, [21] [22] i.e. in arid areas, herbaceous plants are a generator of precipitation and the basis of an ecosystem. Most of the water vapor that turns into dew comes from the air, not the soil or clouds. [23] [24] The taller the herb (surface area is the main factor though), the more dew it produces, [25] [26] so a short cut of the herbs necessitates watering. For example, if you frequently and shortly cut the grass without watering in an arid zone, then desertification occurs.
Most herbaceous plants have a perennial (85%) life cycle but some are annual (15%) or biennial (<1%). [27] Annual plants die completely at the end of the growing season or when they have flowered and fruited, and then new plants grow from seed. [28] Herbaceous perennial and biennial plants may have stems that die at the end of the growing season, but parts of the plant survive under or close to the ground from season to season (for biennials, until the next growing season, when they grow and flower again, then die).[ citation needed ]
New growth can also develop from living tissues remaining on or under the ground, including roots, a caudex (a thickened portion of the stem at ground level) or various types of underground stems, such as bulbs, corms, stolons, rhizomes and tubers. Examples of herbaceous biennials include carrot, parsnip and common ragwort; herbaceous perennials include potato, peony, hosta, mint, most ferns and most grasses. [29]
A biennial plant is a flowering plant that, generally in a temperate climate, takes two years to complete its biological life cycle.
Dew is water in the form of droplets that appears on thin, exposed objects in the morning or evening due to condensation. As the exposed surface cools by radiating its heat, atmospheric moisture condenses at a rate greater than that at which it can evaporate, resulting in the formation of water droplets.
A shrub or bush is a small-to-medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees by their multiple stems and shorter height, less than 6–10 m (20–33 ft) tall. Small shrubs, less than 2 m (6.6 ft) tall are sometimes termed as subshrubs. Many botanical groups have species that are shrubs, and others that are trees and herbaceous plants instead.
A grassland is an area where the vegetation is dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur naturally on all continents except Antarctica and are found in most ecoregions of the Earth. Furthermore, grasslands are one of the largest biomes on Earth and dominate the landscape worldwide. There are different types of grasslands: natural grasslands, semi-natural grasslands, and agricultural grasslands. They cover 31–69% of the Earth's land area.
Alpine tundra is a type of natural region or biome that does not contain trees because it is at high elevation, with an associated harsh climate. As the latitude of a location approaches the poles, the threshold elevation for alpine tundra gets lower until it reaches sea level, and alpine tundra merges with polar tundra.
Castilleja, commonly known as paintbrush, Indian paintbrush, or prairie-fire, is a genus of about 200 species of annual and perennial mostly herbaceous plants native to the west of the Americas from Alaska south to the Andes, northern Asia, and one species as far west as the Kola Peninsula in northwestern Russia. These plants are classified in the broomrape family Orobanchaceae. They are hemiparasitic on the roots of grasses and forbs. The generic name honors Spanish botanist Domingo Castillejo.
A forb or phorb is a herbaceous flowering plant that is not a graminoid. The term is used in botany and in vegetation ecology especially in relation to grasslands and understory. Typically, these are eudicots without woody stems.
In horticulture, the term is used to differentiate a plant from shorter-lived annuals and biennials. It has thus been defined as a plant that lives more than two years. The term is also loosely used to distinguish plants with little or no woody growth from trees and shrubs, which are also technically perennials. Notably, it is estimated that 94% of plant species fall under the category of perennials, underscoring the prevalence of plants with lifespans exceeding two years in the botanical world.
A subshrub or undershrub is either a small shrub or a perennial that is largely herbaceous but slightly woody at the base. The term is often interchangeable with "bush".
In botany, a cortex is an outer layer of a stem or root in a vascular plant, lying below the epidermis but outside of the vascular bundles. The cortex is composed mostly of large thin-walled parenchyma cells of the ground tissue system and shows little to no structural differentiation. The outer cortical cells often acquire irregularly thickened cell walls, and are called collenchyma cells.
The Raunkiær system is a system for categorizing plants using life-form categories, devised by Danish botanist Christen C. Raunkiær and later extended by various authors.
This page provides a glossary of plant morphology. Botanists and other biologists who study plant morphology use a number of different terms to classify and identify plant organs and parts that can be observed using no more than a handheld magnifying lens. This page provides help in understanding the numerous other pages describing plants by their various taxa. The accompanying page—Plant morphology—provides an overview of the science of the external form of plants. There is also an alphabetical list: Glossary of botanical terms. In contrast, this page deals with botanical terms in a systematic manner, with some illustrations, and organized by plant anatomy and function in plant physiology.
Barren vegetation describes an area of land where plant growth may be sparse, stunted, and/or contain limited biodiversity. Environmental conditions such as toxic or infertile soil, high winds, coastal salt-spray, and climatic conditions are often key factors in poor plant growth and development. Barren vegetation can be categorized depending on the climate, geology, and geographic location of a specific area.
Plant life-form schemes constitute a way of classifying plants alternatively to the ordinary species-genus-family scientific classification. In colloquial speech, plants may be classified as trees, shrubs, herbs, etc. The scientific use of life-form schemes emphasizes plant function in the ecosystem and that the same function or "adaptedness" to the environment may be achieved in a number of ways, i.e. plant species that are closely related phylogenetically may have widely different life-form, for example Adoxa moschatellina and Sambucus nigra are from the same family, but the former is a small herbaceous plant and the latter is a shrub or tree. Conversely, unrelated species may share a life-form through convergent evolution.
A woody plant is a plant that produces wood as its structural tissue and thus has a hard stem. In cold climates, woody plants further survive winter or dry season above ground, as opposed to herbaceous plants that die back to the ground until spring.
A stem is one of two main structural axes of a vascular plant, the other being the root. It supports leaves, flowers and fruits, transports water and dissolved substances between the roots and the shoots in the xylem and phloem, engages in photosynthesis, stores nutrients, and produces new living tissue. The stem can also be called the culm, halm, haulm, stalk, or thyrsus.
Herbs are a widely distributed and widespread group of plants, excluding vegetables and other plants consumed for macronutrients, with savory or aromatic properties that are used for flavoring and garnishing food, for medicinal purposes, or for fragrances. Culinary use typically distinguishes herbs from spices. Herbs generally refers to the leafy green or flowering parts of a plant, while spices are usually dried and produced from other parts of the plant, including seeds, bark, roots and fruits.
Herbchronology is the analysis of annual growth rings in the secondary root xylem of perennial herbaceous plants. While leaves and stems of perennial herbs die down at the end of the growing season the root often persists for many years or even the entire life. Perennial herb species belonging to the dicotyledon group are characterized by secondary growth, which shows as a new growth ring added each year to persistent roots. About two thirds of all perennial dicotyledonous herb species with a persistent root that grow in the strongly seasonal zone of the northern hemisphere show at least fairly clear annual growth rings.
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