In botany, a rosette is a circular arrangement of leaves or of structures resembling leaves.
In flowering plants, rosettes usually sit near the soil. Their structure is an example of a modified stem in which the internode gaps between the leaves do not expand, so that all the leaves remain clustered tightly together and at a similar height. Some insects induce the development of galls that are leafy rosettes. [1]
In bryophytes and algae, a rosette results from the repeated branching of the thallus as the plant grows, resulting in a circular outline.
Many plant families have varieties with rosette morphology; they are particularly common in Asteraceae (such as dandelions), Brassicaceae (such as cabbage), and Bromeliaceae. The fern Blechnum fluviatile or New Zealand Water Fern (kiwikiwi) is a rosette plant.
Often, rosettes form in perennial plants whose upper foliage dies back with the remaining vegetation protecting the plant. Another form occurs when internodes along a stem are shortened, bringing the leaves closer together, as in lettuce, dandelion and some succulents. [2] (When plants such as lettuce grow too quickly, the stem lengthens instead, a condition known as bolting.) In yet other forms, the rosette persists at the base of the plant (such as the dandelion), and there is a taproot.
Part of the protective function of a rosette like the dandelion is that it is hard to pull from the ground; the leaves come away easily while the taproot is left intact.
Another kind of protection is provided by the caulescent rosette, which is part of the growth form of the giant herb genus Espeletia in South America, which has a well-developed stem above the ground. [3] In tropical alpine environments, a wide variety of plants in different plant families and different parts of the world have evolved this growth form characterized by evergreen rosettes growing above marcescent leaves. Examples where this arrangement has been confirmed to improve survival, help water balance, or protect the plant from cold injury are Espeletia schultzii and Espeletia timotensis, both from the Andes. [4] [5]
The rosette form is the structure, the relationship of the parts, and the variations within it, as shown in the following study from a herbarium:
As form, "rosette" is used to describe plants that perpetually grow as a rosette and the immature stage of plants such as some ferns.
In botany, a bulb is a short underground stem with fleshy leaves or leaf bases that function as food storage organs during dormancy. In gardening, plants with other kinds of storage organ are also called ornamental bulbous plants or just bulbs.
In botany, a plant shoot consists of any plant stem together with its appendages like leaves, lateral buds, flowering stems, and flower buds. The new growth from seed germination that grows upward is a shoot where leaves will develop. In the spring, perennial plant shoots are the new growth that grows from the ground in herbaceous plants or the new stem or flower growth that grows on woody plants.
Hypochaeris radicata – also known as catsear, flatweed, cat's-ear, hairy cat's ear, or false dandelion – is a perennial, low-lying edible herb often found in lawns. The plant is native to Europe, but has also been introduced to the Americas, Japan, Australia, and New Zealand, where it can be an invasive weed. It is listed as a noxious weed in the northwestern U.S. state of Washington.
Echinacea angustifolia, the narrow-leaved purple coneflower or blacksamson echinacea, is a species of flowering plant in the family Asteraceae. It is native to North America, where it is widespread across much of the Great Plains of central Canada and the central United States, with additional populations in surrounding regions.
In botany, a scape is a peduncle arising from a subterranean or very compressed stem, with the lower internodes very long and hence few or no bracts except the part near the rachis or receptacle. Typically it takes the form of a long, leafless flowering stem rising directly from a bulb, rhizome, or similar subterranean or underwater structure.
Marcescence is the withering and persistence of plant organs that normally are shed, and is a term most commonly applied to plant leaves. The underlying physiological mechanism is that trees transfer water and sap from the roots to the leaves through their vascular cells, but in some trees as autumn begins, the veins carrying the sap slowly close until a layer of cells called the abscission layer completely closes off the vein allowing the tree to rid itself of the leaf. Leaf marcescence is most often seen on juvenile plants and may disappear as the tree matures. It also may not affect the entire tree; sometimes leaves persist only on scattered branches. Marcescence is most obvious in deciduous trees that retain leaves through the winter. Several trees normally have marcescent leaves such as oak (Quercus), beech (Fagus) and hornbeam (Carpinus), or marcescent stipules as in some but not all species of willows (Salix). All oak trees may display foliage marcescence, even species that are known to fully drop leaves when the tree is mature. Marcescent leaves of pin oak complete development of their abscission layer in the spring. The base of the petiole remains alive over the winter. Many other trees may have marcescent leaves in seasons where an early freeze kills the leaves before the abscission layer develops or completes development. Diseases or pests can also kill leaves before they can develop an abscission layer.
Plant reproduction is the production of new offspring in plants, which can be accomplished by sexual or asexual reproduction. Sexual reproduction produces offspring by the fusion of gametes, resulting in offspring genetically different from either parent. Asexual reproduction produces new individuals without the fusion of gametes, resulting in clonal plants that are genetically identical to the parent plant and each other, unless mutations occur.
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.
Lactuca canadensis is a species of wild lettuce known by the common names Canada lettuce, Canada wild lettuce, and tall lettuce. Its true native range is not clear, but it is considered to be a native of the eastern and central parts of North America. It naturalized in the western part of the continent as well as in Eurasia.
A cushion plant is a compact, low-growing, mat-forming plant that is found in alpine, subalpine, arctic, or subarctic environments around the world. The term "cushion" is usually applied to woody plants that grow as spreading mats, are limited in height above the ground, have relatively large and deep tap roots, and have life histories adapted to slow growth in a nutrient-poor environment with delayed reproductivity and reproductive cycle adaptations. The plant form is an example of parallel or convergent evolution with species from many different plant families on different continents converging on the same evolutionary adaptations to endure the harsh environmental conditions.
This glossary of botanical terms is a list of definitions of terms and concepts relevant to botany and plants in general. Terms of plant morphology are included here as well as at the more specific Glossary of plant morphology and Glossary of leaf morphology. For other related terms, see Glossary of phytopathology, Glossary of lichen terms, and List of Latin and Greek words commonly used in systematic names.
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, or thyrsus.
Taraxacum is a large genus of flowering plants in the family Asteraceae, which consists of species commonly known as dandelions. The scientific and hobby study of the genus is known as taraxacology. The genus is native to Eurasia but the two most commonplace species worldwide, T. officinale and T. erythrospermum, were introduced from Europe into North America, where they are invasive aliens. Dandelions thrive in temperate regions and can be found in yards, gardens, sides of roads, among crops, and in many other habitats. Both species are edible in their entirety and have a long history of consumption. The common name dandelion is also given to specific members of the genus.
Krigia is a genus of North American flowering plants in the family Asteraceae. Plants of the genus are known generally as dwarf dandelions or dwarfdandelions.
Espeletia schultzii is a high altitude shrub endemic to the Andes of Venezuela.
Lactuca floridana, commonly known as woodland lettuce, Florida lettuce, or false lettuce is a North American species of wild lettuce. It is native across much of central Canada and the eastern and central United States.
Taraxacum arcticum, the arctic dandelion, is a species of flowering plant belonging to the family Asteraceae. Its native range is Greenland, Northern Europe, Northern Asia and the Northern Russian Far East.
Sonchus fruticosus, the giant sow thistle, is a species of flowering plant in the tribe Cichorieae of the family Asteraceae. It is endemic to the islands of Madeira. The giant sow thistle is an impressive shrub native to the Madeiran evergreen forest habitat and growing up to 4 metres in height.
Silphium perplexumJ.R.Allison is a prairie species in the Asteraceae endemic to the state of Alabama. S. perplexum is commonly known as Old Cahaba rosinweed, a reference to the Cahaba River near which all populations of this species are found.
Taraxacum ceratophorum, also known as the horned dandelion, is a species of flowering plant within the genus Taraxacum and family Asteraceae. This alpine species has a preference for mountainous habitat, where it can be found growing at elevations up to 3000 meters above sea level. It is native to a large portion of the Northern Hemisphere, inhabiting various countries within Asia, Europe and North America.