About the Classification Download. Classification for Kingdom Plantae Down to Class Liliopsida. Click on names to expand them, and on P for PLANTS profiles. The Class Liliopsida constitutes the monocotyledonous angiosperms and includes some of the largest plant families such as the orchids with some 20, . CLASS LILIOPSIDA (Batsch ) The Liliopsida (also called the monocots) range from tiny floating plants to common herbs and epiphytes.
|Published (Last):||25 March 2007|
|PDF File Size:||1.34 Mb|
|ePub File Size:||10.97 Mb|
|Price:||Free* [*Free Regsitration Required]|
The Class Liliopsidda constitutes the liliopsidaa angiosperms and includes some of the largest plant families such as the orchids with some 20, species and the grasses with perhaps 15, species. In the previous chapter we learned how to separate the two major flowering plant groups: In this chapter, we shall do the same by considering representative monocot families.
The liliopsids are considered to form a monophyletic group evolved from an early dicot. Features that are generally common to monocots include vascular bundles that are irregularly distributed in cross-section of the stemleaves with parallel venation, liliposida flower parts in multiples of three.
Although true secondary growth is absent, most growth habits are found in the group including floating and submerged aquatics, lianas, trees, epiphytes, and forbs of all sizes Hahn, The second largest to Orchidaceae and one of the most successful of families of monocotyledons is the grass family, classified as the Family Poaceae or Gramineae and comprising nearly 10, species distributed more widely than any other angiosperm family.
This family is also the most important economically, providing species that are the world’s staple food supply. The grasses have reduced floral structures compared with most angiosperms for the reason luliopsida grasses are almost exclusively pollinated by wind. Therefore, these plants have had no cause to evolve floral structures that are attractive to insect or other animal pollinators.
The grasses also have a fairly specific body plan that is immediately recognizable and very successful for colonizing seasonally dry landscapes, yet modifiable to suit a wide range of ecological conditions.
Grasses have fibrous roots and three kinds of stems: The culm is the main aerial shoot to which leaves and flower head are attached. The culm is a rounded or slightly flattened stem with one or more solid joints known as nodes. The leaves are attached at the nodes and if the stem is not simple but branched, branches arise only at nodes. Roots may also develop from a node where the node comes into contact with the ground as in decumbent and prostrate stems.
The portion of the stem between the nodes is called the internodeand is usually hollow in temperate zone grasses and solid in tropical grasses Rotar, All or a portion of an internode may be surrounded by the basal part of the leaf known as the sheath. A rhizome is a modified stem that grows underground. Rhizomes are jointed thus distinguishable from roots with bladeless leaves scales arising from the joints. Rhizomes enable the grass plant to spread horizontally as new culms develop vertically from the joints.
Thus, grasses with extensive rhizome development will form a turf rather than distinct tufts or bunches.
A stolon is a stem that creeps classs the surface of the ground, and is really a basal branch of the culm that will develop roots and shoots from some or all of its nodes.
Like a rhizome, a stolon results in a spreading or turf forming grass plant.
Grasses display two types of leaves: With but a few exceptions, the green leaves arise at nodes alternately up the culm. Leaves that are concentrated near the base where the internodes are very short are termed basal leaves ; leaves arising at nodes along an elongated culm are cauline leaves. These vegetative leaves typically surround the culm as a sheaththen diverge outward at the “collar” as a long narrow blade with longitudinal parallel venation.
If the veins are conspicuous, the leaf is striate; if the veins are raised, the leaf is ribbed. The sheath of the leaf surrounds and protects the shoot. In some species, the sheath extends beyond the next node, so that consecutive leaf sheaths overlap, hiding the nodes.
The longitudinal edges of the sheath may overlap, completely surrounding the culm, or the sheath may be tubular the margins connate. The upper end of the sheath, known as the sheath mouth is the collar on the lower outer surface that may be produced into short appendages called auricles. On the inner, upper surface of the leaf, between the sheath and the blade, is an outgrowth called a ligule.
Class Liliopsida – definition of class Liliopsida by The Free Dictionary
This may be a flap of membranous tissue or simply a fringe of liliopsidx, an inconspicuous rim, or even absent all together, marked only by dark tissue. Although there is variation in leaf blade shape, most grasses have linear-shaped leaves that are many times longer than wide, with margins that are parallel then taper to a point at the apex.
Grasses that grow in shady places may have lanceolate or even ovate leaf blades. Flowers of grasses are borne in an inflorescence or flower head which terminates the culm and other branches of the stem. Smaller units of the inflorescence are called spikelets and these are arranged on one or more branches in a wide variety of different ways liliopsoda which the standard terminology for liliposida can be applied, but using the spikelet instead of the individual flower. From Wikibooks, open books for an open world.
Magnoliophyta II The Class Liliopsida constitutes the monocotyledonous angiosperms and includes some of the largest plant families such as the orchids with some 20, species and the grasses with perhaps 15, species. Grasses [ edit ]. Retrieved from ” https: Views Read Edit View history. Policies and guidelines Contact us. In other languages Add links.