Encyclopedian Dictionary: June 2013

adnate

Pronunciation key ( ad′nāte ) ad•nate adj. [L. adnatus pp. of adnasci to be born, to grow to or on]. In botany and zoology, congenitally joined together. Said with regard to fused, unlike parts such as stamens and petals; see CONNATE. References Biology of Plants, Fourth Edition, Worth Publishers Inc., Stanford University, Peter H. Raven and Helena Curtis, ©1971 Webster's New World Dictionary of the American Language (College Edition) ©1...

adhesion

Pronunciation key ( əd-hē′zhən )( ad-hē′zhən ) ad•he•sion n. [Fr.; L. adhaesio < pp. of adhaerere see ADHERE]. Sticking together or being stuck together. A sticking together of dissimilar materials. Adherence; to some thing, a devoted attachment. That which adheres. In medicine when normally separate tissues grow together. pl. bands of fibrous tissues by which such tissues are connected. In physics, the force or forces that hold together the dissimilar molecules of substances whose surfaces...

adenosine phosphate

adenosine phosphate (di-, tri-). Called ATP. It is a major source of usable chemical energy in metabolism. On hydrolysis ATP loses one phosphate to become adenosine diphosphate (ADP) with release of usable energy. References Biology of Plants, Fourth Edition, Worth Publishers Inc., Stanford University, Peter H. Raven and Helena Curtis, ©1...

adenine

Pronunciation key ( ad′ə-nēn′ ) ( ad′ə-nin′ ) ( ad′ə-nīn′ ) ad•e•nine n. [aden- + ine]. White, crystalline purine base. C5H5N5 derived from nucleic acid formed in organs such as the pancreas and spleen. It is present in DNA, RNA and nucleotides such as ADP and ATP. References Webster's New World Dictionary of the American Language (College Edition) ©1955 Biology of Plants, Fourth Edition, Worth Publishers Inc., Stanford University, Peter H. Raven and Helena Curtis, ©1...

adaptive radiation

Pronunciation key ( ə-dap′tiv rā′di-ā′shən ) adaptive radiation The evolution from one form of organism to divergent forms with specialized physiology and distinctive behaviors suiting them for new and diverse ways of life. References Webster's New World Dictionary of the American Language (College Edition) ©1955 Biology of Plants, Fourth Edition, Worth Publishers Inc., Stanford University, Peter H. Raven and Helena Curtis, ©1...

adaptation

Pronunciation key ( ad′əp-tā′-shən ) ( ad′ap-tā′shən) ad•ap•ta•tion n. [Fr.; LL. adaptatio, see ADAPT.; L. aptus fit, Fr. adaptare, to fit]. Adapting or being adapted. A thing which results from becoming adapted such as a play being an adaptation of a novel. In biology, a change in structure, development of a peculiar characteristic in an organism's physiology or behavior which better enables it to better fit in and survive in its particular environment. In physiology, the power the eye...

ad-

ad- [L. toward, to]. Prefix that means "toward" or "to". References Biology of Plants, Fourth Edition, Worth Publishers Inc., Stanford University, Peter H. Raven and Helena Curtis, ©1...

active transport

active transport A process which expends energy when a cell moves a substance across its membrane, typically from a position of low concentration to a point of higher concentration, against the diffusion gradient. References Biology of Plants, Fourth Edition, Worth Publishers Inc., Stanford University, Peter H. Raven and Helena Curtis, ©1...

action spectrum

action spectrum Waves from among the light spectrum which a responsive reaction is elicited. References Biology of Plants, Fourth Edition, Worth Publishers Inc., Stanford University, Peter H. Raven and Helena Curtis, ©1...

actinomorphic

Pronunciation key ( ak′ti-nə-môr′fik ) ac•ti•no•mor•phic adj. [Gk. aktis, ray + morphe form]. In biology, having radical symmetry as a starfish or flower that can be divided equally in half in more than one longitudal plane. References Biology of Plants, Fourth Edition, Worth Publishers Inc., Stanford University, Peter H. Raven and Helena Curtis, ©1971 Webster's New World Dictionary of the American Language (College Edition) ©1955 ...

acid

Pronunciation key ( as′id ) ac•id adj. [L. acidus, sour < base ac-, sharp]. Sour; sharp and biting to taste; tart. Substance that dissociates, releasing hydrogen (H-) ions but not hydroxyl (OH+) ions, having a pH of less than 7. see base. In chemistry, a compound that can react with a base to form a salt, the hydrogen of the acid being replaced by a positive ion; according to modern theory, a compound yielding hydrogen ions (protons) to a base in a chemical reaction: in water solution,...

achene

Pronunciation key ( ā-kēn′ ) a•chene n. [Gk. a-, not, + chainein to gape]. Any small, dry fruit with a single seed whose thin outer coat (pericarp) does not burst when ripe. References Biology of Plants, Fourth Edition, Worth Publishers Inc., Stanford University, Peter H. Raven and Helena Curtis, ©1971 Webster's New World Dictionary of the American Language (College Edition) ©1...

accessory pigment

accessory pigment Pigment which captures light energy and converts it into chlorophyll a. References Biology of Plants, Fourth Edition, Worth Publishers Inc., Stanford University, Peter H. Raven and Helena Curtis, ©1...

absorption spectrum

Pronunciation key ( ăb·sôrp′shŭn spĕk′trŭm ) ab•sorp•tion spec•trum Spectrum light waves which are absorbed by a particular pigment. References Biology of Plants, Fourth Edition, Worth Publishers Inc., Stanford University, Peter H. Raven and Helena Curtis, ©1...

abscission zone

Pronunciation key ( ăb·sizh′ŭn ) abscission zone A delicate layer of thin-walled cells which extend across the stem of a leaf or fruit, and breaking of which results in the organ to separate from the plant. References Biology of Plants, Fourth Edition, Worth Publishers Inc., Stanford University, Peter H. Raven and Helena Curtis, ©1...

abscission

Pronunciation key ( ab-sizh′ən ) ( ab-sish′ən ) ab•scis•sion n. [L. abscissio see ABSCISSA]. A cutting off such as by surgery. Abrupt stop, such as in mid-sentence for rhetorical effect. The dropping of leaves, flowers, fruit or other parts of the plant normally following the formation of an abscission zone. References Biology of Plants, Fourth Edition, Worth Publishers Inc., Stanford University, Peter H. Raven and Helena Curtis, ©1971 Webster's New World Dictionary of the American Language...

abscisic acid

abscisic acid [L. abscissus cut off]. Plant hormone which is involved in abscission and dormancy. References Biology of Plants, Fourth Edition, Worth Publishers Inc., Stanford University, Peter H. Raven and Helena Curtis, ©1...

Å ( abbreviation )

Pronunciation key ( ăng′strŭm ) Å After A.J. Angstrom, a swiss physicist (1814-1874). A unit of length equal to .0001 of a micron; Abbreviation Å. References Biology of Plants, Fourth Edition, Worth Publishers Inc., Stanford University, Peter H. Raven and Helena Curtis, ©1...

Thallophyta

Thallophyta "In systems in which the algae and fungi are regarded as plants, they are often grouped as a subkingdom Thallophyta, the thallophytes: organisms with no highly differentiated tissues, such as root, stem, or leaf, and no vascular tissues (xylem and phloem). The land plants are then grouped into a second subkingdom, Embryophyta, in which the zygote develops into a multicellular embryo still...

Angiospermae

Angiospermae The itis.gov database lists two entries for Kingdom Plantae: Angiospermae – not accepted. Angiospermae – accepted – angiosperma, angiospermes, angiosperms, flowering plants. "The flowering plants. Seed plants in which the ovules are enclosed in a carpel (in all but a very few genera), and the seeds at maturity are born within fruits. They are extremely diverse vegetatively but characterized by the flower, which is basically insect-pollinated. Other modes of pollination, such as...

Gnetinae

Gnetinae "Seed plants of three very distinctive genera with the inner layers of the integument prolonged into a tube. The only gymnosperms in which vessels occur. There are about 70 species." References Biology of Plants, Fourth Edition, Worth Publishers Inc., Stanford University, Peter H. Raven and Helena Curtis, ©1...

Ginkgoinae

Ginkgoinae The term "Ginkgoinae" does not appear in the itis.gov database, it appears that Ginkgoinae may be a synonym of the accepted name which remains to be listed. The accepted names are found below in the taxonomic hierarchy table. "Ginkgo. Seed plants with active cambial growth and fan-shaped leaves with open dichotomous venation. The ovules are not enclosed and are fleshy at maturity. Sperm...

Cycadinae

Cycadinae "Cycads. Seed plants with sluggish cambial growth and pinnately compound, palmlike or fernlike leaves. The ovules are not enclosed. The sperm are flagellated and motile, but are carried to the vicinity of the ovule in a pollen tube. Cycads are gymnosperms. There are nine genera and about 100 species." References Biology of Plants, Fourth Edition, Worth Publishers Inc., Stanford University, Peter H. Raven and Helena Curtis, ©1...

Coniferinae

Coniferinae The conifers. Seed plants with active cambial growth and simple leaves, in which the ovules are not enclosed and the sperm are not flagellated. There are some 50 genera and about 550 species, the most familiar group of gymnosperms. References Biology of Plants, Fourth Edition, Worth Publishers Inc., Stanford University, Peter H. Raven and Helena Curtis, ©1...

Filicineae

Filicineae "The ferns. They are mostly homosporous although some are heterosporous. The gametophyte is more or less free-living and usually photosynthetic. Multicellular gametangia and free-swimming sperm are present. There are about 11,000 species." References Biology of Plants, Fourth Edition, Worth Publishers Inc., Stanford University, Peter H. Raven and Helena Curtis, ©1...

Pterophytina

Pterophytina "Ferns, gymnosperms, and flowering plants. Although diverse, these groups possess in common the megaphyll, which in certain genera has become much reduced. There are about 260,000 species." References Biology of Plants, Fourth Edition, Worth Publishers Inc., Stanford University, Peter H. Raven and Helena Curtis, ©1...

Sphenophytina

Sphenophytina "The horsetails. Homosporous vascular plants with jointed stems marked by conspicuous nodes and elevated siliceous ribs and sporangia borne in a strobilus at the apex of the stem. Leaves are scalelike. Sperm are motile. ALthough now thought to have evolved from a megaphyll, the leaves of the horsetails are structurally indistinguishable from microphylls. There is one genus, Equisetum, with about two dozen living species." References Biology of Plants, Fourth Edition, Worth Publishers...

Lycophytina

Lycophytina "The lycophytes. Homosporous and heterosporous vascular plants with microphylls; extremely diverse in appearance. All lycophytes have motile sperm. There are five genera and about 1,000 species." References Biology of Plants, Fourth Edition, Worth Publishers Inc., Stanford University, Peter H. Raven and Helena Curtis, ©1...

Tracheophyta

Tracheophyta "The vascular plants. Terrestrial plants with complex differentiation of organs into leaves, roots, and stem. Motile cells, if present, (and then only in the form of male gametes) are elongate or (if wound up) top-shaped, propelled by many cilia. The vascular plants have well-developed strands of conducting tissue for the transport of water and organic materials. The main trends of evolution in the vascular plants involve a progressive reduction in the gametophyte, which is green and...

Musci

Musci Presently, Musci, Taxonomic Serial No.: 500008 is no longer accepted. The current accepted name is Bryophytina, Taxonomic Serial No.: 846121 "The mosses. The gametophytes are leafy. Sporophytes have complex patterns of dehiscense. Rhizoids are multicellular. Stomata are present on the sporophyte. There are about 14,500 species." References Biology of Plants, Fourth Edition, Worth Publishers Inc., Stanford University, Peter H. Raven and Helena Curtis, ©1...

Antherocerotae

Antherocerotae "The hornworts. The gametophytes are thallose. The sporophyte grows from a basal intercalary meristem for as long as conditions are favorable. Stomata are present on the sporophyte. There are about 100 species." References Biology of Plants, Fourth Edition, Worth Publishers Inc., Stanford University, Peter H. Raven and Helena Curtis, ©1...

Hepaticae

Hepaticae Presently, Hepaticae, Taxonomic Serial No.: 14196 is no longer accepted. The accepted classification is Marchantiophytina, Taxonomic Serial No.: 846120 "The liverworts. The gametophytes are thallose or leafy rhizoids, single-celled and the sporophytes relatively simple in construction. There are about 9,000 species. Biology of Plants, Fourth Edition, Worth Publishers Inc., Stanford University, Peter H. Raven and Helena Curtis, ©1971 References Biology of Plants, Fourth Edition, Worth...

Bryophyta

Bryophyta "Mosses, hornworts and liverworts. Multicellular plants with the photosynthetic pigments and food reserves similar to those of the green algae. They have gametangia with a multicellular sterile jacket one cell layer thick. The sperm are biflagellate and motile. Gametophytes and sporophytes both exhibit complex multicellular patterns of development, but the conducting tissues are usually completely absent and not well differentiated when present. Most of the photosynthesis in these primarily...

Chlorophyta ( Infrakingdom ) and ( Division )

Chlorophyta "Green algae. Unicellular or multicellular plants characterized by chlorophylls a and b and various carotenoids. The carbohydrate food reserve is starch. Motile cells have two whiplash flagella at the apical end. True multicellular genera do not exhibit complex patterns of differentiation. Multicellularity has arisen at least three times, and quite possibly more often. There are about 7,000 known species and possibly many more." Biology of Plants, Fourth Edition, Worth Publishers Inc.,...

Fungi Imperfecti

Fungi Imperfecti "Mainly fungi with the characteristics of Ascomycetes but in which the sexual cycle has not been observed; a few probably belong to other classes. The Fungi Imperfecti are classified by their asexual spore-bearing organs. There are some 25,000 species." Biology of Plants, Fourth Edition, Worth Publishers Inc., Stanford University, Peter H. Raven and Helena Curtis, ©1971 References Biology...