Since all the systems of classification and nomenclature of plants are based on morphological and anatomical features, it is necessary for a student of systematic botany to attain ability to recognize the characters by which one kind of plant may be distinguished from another.
This requires knowledge of plant structures and familiarity with the technical terms by which they and their components are known.
Such a study, which is known as phytography, constitutes an important part of taxonomy. Though the terminology used in describing the plant structures is extensive and unduly technical, but they are concise and do give accuracy to the description. Since we are concerned here only with the angiosperm plants, terminology used to describe them is given below. A plant is described in a set sequence, starting from its habit and roots and going up to its floral diagram and floral formula.
A. Plant Type (Habit and Habitat):
Whether (1) annual, or (2) biennial, or (3) perennial, or (4) herb, or (5) shrub, or'(6) tree, or (7) Climber, or (8) Liana, or (9) Creeper, or (10) Epiphyte, or (11) Parasite, or (12) aquatic, or (13) xerophyte.
B. Root:
Whether tap root or adventitious root, or some specialized roots such as (1) modulated roots, (2) fibrous roots, (3) tuberous roots, (4) stilt roots, (5) epiphytic roots, (6) climbing roots, (7) aquatic roots.
C. STEM:
Whether (1) aerial stem, or (2) erect stem, or (3) weak stem (see if it is climber, twiner, trailer or creeper), or (4) reduced stem or (5) underground modified stem, such as phylloclade, thorn, prickle, tendril, and bulbil.
Brandling of stem:
Whether (1) lateral or (2) dichotomous. If lateral-whether it is racemose type or cymose type. If cymose type, whether it is uniparous (i) helicoid or (ii) scorpioid, or biparous cyme.
Buds:
Whether (1) Lateral or axillary, or (2) terminal bud or (3) pseudo-terminal bud.
Shape of the stem:
It may be (1) cylinderical or (2) angular or (3) flattened.
Surface of the stem:
Whether (1) glaucous, or (2) glabrous, or (3) succulent, or (4) hairy, or (5) spiny, or (6) prickly.
D. Leaves:
(I) Structure of Leaf:
Whether stipidate or exstipulate; petiolate or sessile; simple or compound.
(II) Duration of Leaf:
Whether (1) persistent, or (2) deciduous, or (3) evergreen, or (4) fugacious.
(III) Leaf Insertion:
Whether (1) cauline, or (2) ramal, or (3) radical.
Leaf Arrangement:
Whether (1) opposite, or (2) decussate, or (3) alternate, or (4) distichous, or (5) whorled.
(IV) Leaf Base:
Whether (1) auriculate, or (2) amplexicaul, or (3) semi-amplexicaul, or (4) Perfoliate, or (5) connate-perfoliate, or (6) attenuate, or (7) cuniate, or (8) oblique, or (9) obtuse, or (10) truncate, or (11) cordate, or (12) sagittate, or (13) hastate, or (14) pellate.
(V) Stipules:
Whether (1) free lateral, or (2) scaly, or (3) adnate, or (4) inter-petiolar, or (5) Ochreate, or (6) foliaceous, or (7) bud-scales.
Sometimes stipules are modified into certain peculiar structures such as spines and tendrils, so please describe them accordingly.
(VI) Leaf Blade:
(a) Form of Leaf Blade:
Whether (1) subulate, or (2) acicular, or (3) filiform, or (4) linear, or (5) lorate, or (6) lanceolate, or (7) ovate, or (8) oval, or (9) elliptical, or (10) oblong, or (11) oblanceolate, or (12) spatulate, or (13) cuneiform, or (14) runcinate, or(15) obovate, or (16) pan- durate, or (17) deltoid, or (18) rhoinboidal, or (19) reniform, or (20) orbicular.
(b) Incision of Leaf Blade:
Whether (1) entire, or (2) undulate, or (3) sinuate, or (4) crenate, or (5) serrate, or (6) serrulate, or (7) double-serrate, or (8) dentate, or (9) denticulate, or (10) ciliate, or (11) spinous, or (12) incised, or (13) lacerate, or (14) lanciniate, or (15) lobed, or (1G) cleft, or (17) parted, or (18) pinnatifid, or (19) palmatifid, or (20) crispate.
(VII) Leaf Apices:
Whether (1) obtuse, or (2) acute, or (3) acuminate (or caudate), or (4) cuspidate, or (5) truncate, or (6) retuse, or (7) emarginate, or (8) mucronate, or (9) cirrhose (orcirrose).
(VIII) Surface of the Leaf:
Whether (1) glabrous, or (2) rough, or (3) glutinous, or (4) glaucous, or (5) spiny, or (6) hairy, or (a) pubescent, or {b) puberulous), or (7) pilose, or (8) villous, or (9) tomentose, or (10) floccose, or (11) hispid, or (12) hirsute, (13) strigose, or (14) mealy, or (15) pruinose.
(IX) Venation of the Leaf:
Whether (1) parallel venation (i) simple parallel, or (ii) penniparallel, or (2) netted (reticulate) venation (i) palmate or (ii) pinnate).
Compound Leaf:
Whether (1) unipinnate (or just pinnate), or (2) bipinnate, or (3) trip- innate, or (4) decompound, or (5) palmate.
E. Inflorescence:
Whether (A) Racemose, or (B) Cymose, or (C) Some special type.
If (A) Racemose (or Indeterminate), then whether (1) Raceme, or (2) spike, or (3) spikelet, or (4) catkin, or (5) spadix, or (6) corymb, or (7) umbel, or (8) capitulum.
If (B) Cymose then whether (1) Uniperous ((i) Helicoid or (ii) Scorpioid), or (2) biperous, or (3) multiperous.
If (C) Special Type, then whether (1) cyathium, or (2) verticillaster, or hypanthodium.
F. The Flower:
Whether (1) regular (or actinomorphic), or (2) zygomorphic (or irregular); complete or incomplete; pedicelate or sessile; hermaphrodite (perfect) or unisexual (imperfect). If unisexual, then whether male (staminate) or female (pistilate).
(i) Arrangement of floral appendages on the receptacle:
Whether (1) hypogynous, or (2) perigynous, or (3) epigynous.
(ii) The Calyx:
Whether (1) sepaloid, or (2) petaloid; (1) regular (2) zygomorphic, or (3) irregular; (1) polysepalous (or aposepalous), or (2) connate, or (3) gamosepalous (or synsepalous).
(iii) The Corolla:
Whether (1) polypetalous, or (2) gamopetalous, or (3) connate (completely or incompletely).
(A) If polypetalous and regular corolla, then whether (1) cruciform, or (2) caryo- phyllaceous, or (3) rosaceous.
(B) If gamopetalous and regular corolla, then whether (1) companulate or bell-shaped, or (2) tubular, or (3) infundibuliform (or funnel-shaped), or (4) rotate (or wheel- shaped).
(C) If zygomorphic and polypetalous corolla, then whether paplionaceous or not.
(D) If zygomorphic and gamopetalous corolla, then whether (1) bilabiate, or (2) personate, or (3) ligulate.
(iv) Aestivation of Calyx and Corolla:
Whether (1) valvate aestivation, or (2) twisted aestivation, or (3) imbricate aestivation, or (4) vexillary aestivation.
(v) The Androecium:
(A) Attachment of the filament to the anther:
Whether (1) basi- fixed, or (2) adnate, or (3) dorsifixed, or (4) versatile.
(B) Cohesion of stamens:
Whether (1) monoadelphous, or (2) diadelphous, or (3) polyadelphous, or (4) syngenesious, or (5) synandrous.
(C) Adhesion of Stamens:
Whether (i) epipetalous, or (2) epiphyllous, or gynandrous.
(D) Length of Stamens:
Whether (1) didynamous, or (2) tetradynamous.
(E) Correlationship between length of stamens and length of corolla:
Whether (1) inserted, or (2) exserted.
(vi) Gynoecium:
Whether (1) syncarpous, or (2) apocarpous.
(i) Stigma:
Whether (1) knob-shaped, or (2) slightly pointed, or (3) flattened, or (4) elongated.
(ii) Style:
Whether (1) terminal (or apical), or (2) lateral, or (3) gynobasic, or (4) petaloid.
(iii) Placentation:
Whether (1) marginal, or (2) axile, or (3) parietal, or (4) central, or (5) free-central, or (6) basal, or (7) superficial.
G. The Fruit:
(I) In respect to composition:
Whether (I) simple, or (2) aggregate, or (3) multiple
(II) In respect to texture or consistency:
(1) fleshy, or (2) dry fruits, (i) If Fleshy Fruit: Then whether (A) Berry, (B) Drupe, or (C) Pome. If Berry: Then whether (1) pepo, or (2) hesperidium.
If Dry Fruit: Then whether (1) dehiscent or (2) indehiscent.
If Dehiscent: Then whether (1) follicle, or (2) legume (pod), or (3) siliqua, or (4) capsule. If Indehiscent: Then whether (1) ach ne, or (2) caryopsis, or (3) nut, or (4) samara.
Floral Formula and Floral Diagram:
Floral Formula:
It is a simple device to describe morphological features of various floral pans with the help of certain standard symbols. These symbols, when co-n biped, constitute the so-called— floral formula for a particular flower.
The main symbols are as under:
