Bacteriostatic - Using for a substance which inhibits the growth and / or multiplication of bacteria, but does not kill them.

Basal Body - (i) Used for the part of the thallus of the Balstocladiaceae which is fixed to the substrate byrhizoids the lower end. (ii) Used for a deeply staining granule which is present at the base of a flagellum. It may be the centrosome. See Blepharoplast.

Basal Cell - (i) Used for the lowest cell which is cut off from the antheridial initial of the Filicales and Hepaticae.
(ii) Used for the lower cell which is cut off from the antheridial initial of the Heparicae. It remains sterile.

(iii) Used for one of the pair of cells formed by the initial division of a germinating spore of the Lycopodinae, in the early stages of the development of the gametophyte. It gives rise to a rudimentary rhizoidal cell.

(iv) A uninucleate cell which may be the oogonium in the Uredinales>

Basal Placentation - Type of placentation occurring in unilocular ovary having only one ovule in which placenta develop at the base of ovary e.g., in Polygonum sp.

Base Analogue - A chemical resembling a natural purine or pyrimidine molecule to the extent that it may be incorported into DNA during replication or RNA synthesis.

Base Number (Basic number). The number of chromosomesly between 6 and 13 and represented by symbol X.
Base Pair - One of the pairs of bases forming the cross-links in the DNA molecule. They are always paired in the following manner: Adenine and Thymine, Guanine and Cytosine or 5methyl cytosine.

Base Ratio. A ratio between quantities of one base to another base or one base pair to another base pair in DNA. Ratio of A:T and G: C is always one. Comparison of base pair ratios, A + T: G + C percentage G + C of total remains constant in a species but different in different species.

Base Triplet Hypothesis - According to this hypothesis, the shortest sequence of any four bases that could specify all the types of amino acids found in proteins is three.

Basidiocarp. The reproductive organ of all basidiomycete fungi (except Ustilaginales and Uredinales) which are bearing basidia. It may be shaped like a mushroom, bracket, hollow sphere or cylinder. Much of it is composed of sterile pseudoparenchymatous tissue. The basidia are borne in a fertile layer termed hymenium.

Basidiospore - A haploid spore, 4 in number and borne on outer surface of basidium in basidiomycete fungi.

Basidium - Used for the structure in basidiomycete fungi which bears basidiospores, usually on projections called sterigmata. Each basidium is usually one-celled but segmented in some e.g., in Ustilaginales and Uredinales.

Basifixed - Used for describing an anther which gets joined to filament at it is bases. Compare dorsifixed versatile.

Basipetal - Developing so that the oldest structures are at the apex, and the youngest at the base.

Bast. Sometimes used to mean 'phloem' and sometimes to mean 'bast-bibre'. A very vague term which, should not be used.

B-Chromosome - (Accessory Chromosome, Supernumerary Chromosome.) Used for any of a number of small chromosomes found in some organisms in addition to the fixed number of stable Chromosomes characteristic of the species (A-chromosomes). They 'are widely distributed, and found to be in 80 genera of 20 families of plant. Their number, may be different in the members of a species and even in an organism with greater number found in gametic nucleus. They are composed of heterochromatin largely and appear to have no effect in many cases but in large number of cases, may be deleterious.

Beaded - Used of the gill of an agaric which is having a row of small droplets of liquid along its edge.

Beaked - Having a10ng, pointed prolongation.

Bearded. (i) Possessing many awns as the ears of Festuca ambigua.>

(ii) Possessing any type of stiff hairs e.g., hairy lower surface of petals of Ires pseudacorus.

Beaumont Period - Used for 48 hours period during which minimum temperature is 10C and relative humidity 75 percent or more. This period found out by meterological data predicted that an outbreak of patato late blight may take place after this period.

BeltTransect - A narrow strip of land which is a taken as a sample of an area in studying the vegetation.

Bennettitales. An order of Gymnosperms of the Mesozoic, bearing bisporangiate strobili, having the megasporophylls and microsporophylls in a spiral inside a cluster of sterile leaves, i.e., rather like an angiosperm flower.

Benthos - Organisms which are living or near the botton of a large mass of water.

Berry(Bacca). A fleshy indehiscent fruit which has many seeds. It is developed from mono or polycarpellary, superior or inferior ovary with axile or parieta1 placentation. Epicarp is forming outer dry cover, mesocarp fleshy and endocarp membranous e.g., fruit of tomato, brinjal, banana, grape.

Betacyanin - Any of nitrogen-having red pigments e.g., betanidin, which replace and perform the function of floral pigment anthocyanin in certain plants.

Betalain. A class ofnitrogen-having pigment hich include betacyanins and betaxanthins, and occur in plants ofcertain families which have been traditionally placed in Centrospermae (except family Cactaceae though some have placed this family in this group on the basis of presence of betalain). These pigments have been found to replace and function as anthocyanins.

Betaxanthin. Any ofnitrogen-containing yellow pigments which belong to group ofpigments betalain and replace and function such as anthocyanin floral pigment in certain families.

Between Race - A race of plants intermediate in character between the typical species and one ofits well-marked subspecies or varieties.

Bicapsular. A capsule which consists of two chambers.

Bicarpellary, Bicarpelate - A gynoecium having 2 carpels.

Bicollateral Bundle - A vascular bundle having phloem inside and outside the xylem.

Biconic. Looking like to cones which are placed base to base.

Biconjugate - A compound leaf having two main ribs, each bearing a pair of leaflets.

Biennial. A plant developing vegetatively, and producing a food storage organ in the first year. It flowers in the second year only, and it then dies.

Biflagellate. A group of the Phycomycetes with spores possessing two flagella.

Biflagellate - Possessing two flagella.

Bifoliate, Bifolioate - Used for a compound leaf with two leaflets. Bifurcate. Forked, or twice forked.

Biflavonyls. The dimers of flavone apigenin. Belonging to flavonoids, widely found in gymnosperms, scarse or absent in other plant groups.