In botanical leaf taxology, the word decussate describes an opposite pattern of leaves which has successive pairs at right angles to each other (i.e. rotated 90 degrees along the stem when viewed from above). In effect, successive pairs of leaves cross each other. Basil is a classic example of a decussate leaf pattern.
What is Decussate leaf arrangement?
In botany, decussate leaves are arranged along a stem in a way that causes pairs of them to overlap each other. You can use decussate as an adjective or a verb — either way, it's a technical term most commonly used by scientists.
What is opposite and Decussate leaves?
A pair of leaves at one node stands at right angle to the next upper or lower pair so that the four vertical rows are formed on the stem and this type is called as opposite decussate phyllotaxy. eg., Calotropis, Zinnia, Tulsi, etc.
What plants have Decussate leaves?
Decussate arrangement of leaves is characteristic of the mint family (Lamiaceae), themaple family (Aceraceae), and some members of the milkweed family (Asclepiadaceae), such as Asclepias viridis.
What is Decussate phyllotaxy?
In decussate phyllotaxy, two successive pairs of leaves occur perpendicular to each other. Example include Catharanthus roseus. In superposed phyllotaxy, the pairs of leaves are in the same plane.
What is the meaning of the word Decussate?
to intersect or cross: to intersect or cross.
What is spiral leaf?
Leaf arrangement The basic arrangements of leaves on a stem are opposite and alternate (also known as spiral). Leaves may also be whorled if several leaves arise, or appear to arise, from the same level (at the same node) on a stem.
What are the 4 types of leaf arrangements?
The arrangement of leaves on a stem is known as phyllotaxy; leaves can be classified as either alternate, spiral, opposite, or whorled.
What are the different types of leaf?
There are two different types of leaves – simples leaves and compound leaves. The other types of leaves include acicular, linear, lanceolate, orbicular, elliptical, oblique, centric cordate, etc. They perform the function of photosynthesis and help in the removal of excess water from the aerial parts of the plant.
What is a circle of leaves called?
A wreath is a circle of leaves or flowers which someone wears around their head.
What is opposite and Decussate type of phyllotaxy?
So, the correct option is 'Calotropis'.
What is phyllotaxy Class 11?
Phyllotaxy is the term used to describe the arrangement of leaves around the stem. The proper arrangement of leaves is important for providing sunlight and photosynthesis. Leaves arise from the node of the stem.
What are the three types of phyllotaxy?
Phyllotaxy is the pattern or arrangement of leaves on the stem or branch of a plant. Alternate, whorled, and opposite are the three kinds of phyllotaxy.
What are opposite leaves?
In opposite-leaved plants, the leaves are paired at a node and borne opposite to each other. A plant has whorled leaves when there are three or more equally spaced leaves at a node.
What are the examples of opposite leaves?
Opposite Leaf ArrangementAsh trees (Fraxinus spp.). The ash tree has a compound leaf, which is also composed of leaflets arranged oppositely.Fringe tree (Chionanthus virginicus)Maple trees (Acer spp.)Olive trees (Olea spp.)Viburnums (Viburnum spp.)
What is opposite and superimposed arrangements?
Opposite superposed is a type of phyllotaxy in which successive pairs of leaves are present just above each other, in such a way that all leaves appears to be present in one plane, overlapping one another.
What is opposite superposed?
(a) Opposite and Superposed: The opposite leaves of successive nodes are superposed or lie exactly above those of the lower node. For example, Quisqualis, Syzygium. (b) Opposite and Decussate: Opposite leaves of successive nodes lie at right angles to each other so that four rows of leaves are formed.
What are leaves used for?
While leaves often function in photosynthesis, they can be modified to play many other roles. As spines, they are sharp, pointy defensive structures. As tendrils, they provide support for climbing. Leaves may also be non-photosynthetic and modified for food storage. In low-nutrient environments, some carnivorous plants have leaves that have been modified to capture prey.
Where are leaves borne?
Lateral appendages: Leaves are borne laterally on stems (in other words, leaves occur on the sides of stems).
What are the leaves of a Ginkgo?
Feature image: Ginkgo ( Ginkgo biloba) leaves that were shed from trees in the fall. Ginkgo leaves have dichotomous venation, or a pattern of venation in which the veins fork one or more times. Credit: E.J. Hermsen (DEAL).
How are leaves arranged?
Leaves are arranged in a regular sequence, known as phyllotaxy (or phyllotaxis) around the stem. There are many different terms that can be used to described phyllotaxy. Some terms indicate how many leaves occur per node. A node is a region on a stem where one or more leaves are attached. The basic terms describing the number of leaves per node are as follows:
What is the function of leaves in a plant?
The primary function of leaves is to carry out photosynthesis. Photosynthesis is the process by which a plant makes its food.
Which part of the leaf is columnar?
In a leaf with a thin, broad lamina, cells in the upper part of the mesophyll may be columnar ( palisade parenchyma or palisade mesophyll), whereas cells in the lower part may be loosely organized ( spongy parenchyma or spongy mesophyll ).
Where are leaflets attached to the petiole?
In a palmately compound leaf, the leaflets are attached to the end of the petiole in a palmate arrangement (to remember the structure of a palmately compound leaf, think of the leaflets like fingers radiating from the palm of a hand). In a palmately compound leaf, there is no rachis.
What is the Latin word for "decussatus"?
Latin decussatus, past participle of decussare to arrange crosswise, from decussis the number ten, numeral X, intersection, from dec em + ass-, as unit — more at ace. Keep scrolling for more.
Why was the word "decussate" coined?
A man named Sir Thomas Browne coined decussate in the 17th century to discuss the crossing fibers that make up human anatomy-for instance, skin tissue. The word continues to be found primarily in scientific contexts today.
What is the name of the plant with a flat rosette?
Petrocosmea rosettifolia has a conspicuously dense and flat rosette similar to the “Dinner plate” ( Aeonium tabuliforme, Crassulaceae). The dense and perfectly spiral arrangement of the leaves of Petrocosmea rosettifolia results in a kind of “Dinner plate”.
How many leaves does Sinningia leucotricha have?
Sinningia leucotricha is a rarity, a Gesneriad with a single whorl of four leaves. Anisophylly. Unequal size of the two leaves of a leaf pair (anisophylly) is frequent. Pronounced anisophylly is essentially combined with leaf asymmetry and changes in the divergence angles.
What is spiral leaf arrangement?
Spiral leaf arrangement. This kind of leaf arrangement is less common in Gesneriaceae. In the New World Gesneriaceae this pattern is found in Gesneria, Rhytidophyllum, and a few others. A spiral phyllotaxis is often found in rosette plants, e.g. in Saintpaulia (now included in Streptocarpus, Nishii et al.
Where are the leaves on an anisophyllous plant?
In strongly anisophyllous plants the smaller leaves are often reduced to small, stipule-like appendages placed in two adjacent ranks on one side of the shoot axis, while the larger and strongly asymmetrical leaves are arranged in two nearly opposite ranks on the other side.
