In this article we will discuss about:- 1. Characters of Scrophulariaceae 2. Distribution of Scrophulariaceae 3. Economic Importance 4. Affinities 5. Important Type.
Characters of Scrophulariaceae
Plants mostly herbs; leaves alternate or opposite, exstipulate; flowers zygomorphic and hypogynous, hermaphrodite; calyx gamosepalous; corolla gamopetalous; stamens four or two, if four didynamous; epipetalous; gynoecium bicarpellary, syncarpous, bilocular, axile placentation with many ovules; fruit capsule or berry; seeds endospermic.
A. Vegetative characters:
Habit:
Mostly herbs (Antirrhinum) or shrubs rarely trees (Paulownia), climbers (Maurandia), root parasites (Pedicularis).
Root:
Branched tap root system.
Stem:
Herbaceous, or woody (Paulownia) aerial, erect.
Leaves:
Alternate, or opposite, rarely whorled (Veronica), simple; in Limnophila leaves are dimorphic, exstipulate, margin entire, unicostate reticulate, in parasitic species leaves are reduced.
B. Floral characters:
Inflorescence:
Cymose or racemose, it may be spike, rarely solitary axillary (Scoparia, Striga densiflora).
Flower:
Bracteate, pedicellate, or sessile (Lindenbergia), hermaphrodite, pentamerous, hypogynous, complete, zygomorphic, rarely actinomorphic, (Verbascum, Veronica).
Calyx:
Sepals 5, rarely 4 (Veronica, Scoparia), gamosepalous, imbricate or valvate aestivation, persistent; calyx teeth may be 2/5, campanulate or shortly tubular; inferior.
Corolla:
Petals 5, gamopetalous, zygomorphic petals, sometimes two petals fused (Veronica), campanulate (Digitalis), spurred (Linaria); saccate (Antirrhinum), imbricate aestivation, inferior, variously coloured.
Androecium:
Stamens 4 in Digitals, 5 in Verbascum or 2 in Veronica; when didynamous and one staminode present (Digitalis); epipetalous, polyandrous; anthers basifixed or dorsifixed, dithecous, filament short, introrse.
Gynoecium:
Bicarpellary, syncarpous, superior, bilocular, axile placentation, ovules many in each loculus; style short, simple; stigma bifid; usually nectariferous disc present below the ovary.
Fruit:
A capsule or berry.
Seed:
Endospermic.
Pollination:
Entomophilous rarely self pollination in Veronica.
Floral Formula:
Distribution of Scrophulariaceae:
It is commonly called ‘Snapdragon family’. It includes 220 genera and 3000 species which are distributed all over the world but most abundant in temperate regions. In India it is represented by 273 species.
Economic Importance of Scrophulariaceae:
1. Medicinal:
Digitalis is used in heart diseases. The leaves of Verbascum thapsus are used in asthma and pulmonary complaints. The juice of leaves of Torenia asiatica is considered a cure for gonorrhoea. The juice of Lindenbergia indica is given in bronchitis. Anticharis is used in diabetes.
2. Ornamentals:
Antirrhinum, Veronica, Linaria, Mimulus, Cymbalaria, Russelia, Torenia and Digitalis are cultivated for ornamental purposes.
Primitive characters:
1. A few shrubs and trees.
2. Leaves simple and alternate {Linaria, Antirrhinum).
3. Flowers hermaphrodite, hypogynous and rarely actinomorphic (Verbascum thapsus).
4. Stamens dithecous.
5. Seeds endospermic.
Advanced characters:
1. Plants mostly herbs.
2. Leaves exstipulate.
3. Flowers zygomorphic.
4. Calyx gamosepalous.
5. Corolla gamopetalous.
6. Stamens epipetalous.
7. Reduction in the number of stamens
8. Gynoecium bicarpellary, syncarpous.
Affinities of Scrophulariaceae:
Hallier regarded Scrophulariaceae as a primitive component of the Tubiflorae and related to Globulariaceae and Lentibulariaceae. Bessey treated this family as one of the advanced members of his order Scrophulariales and probably derived from Bignoniaceae.
Rendle placed the family in Tubiflorae but kept apart Convolvulaceae which has been kept in the monotypic order Convolvulales. This family Scrophulariaceae is undoubtedly very much allied to Solanaceae but is separated by zygomorphic corolla, reduction in number of stamens and medianly placed carpels.
It is also related to Lamiaceae and Acanthaceae but differs from them due to alternate phyllotaxy, form of corolla, nature of ovary and characters of fruits.
Common plants of the family:
1. Antirrhinum majus (Snapdragon or dog flower):
Ornamental herb cultivated in winter.
2. Mimulus gracilis (Donkey flower):
An ornamental herb.
3. Digitalis purpurea (Foxglove):
A common ornamental herb with medicinal value.
4. Linaria vulgaris (Toad flax):
A beautiful herb.
5. Veronica:
Cultivated herb with 4 sepals, 4 petals and 2 stamens.
6. Bonnaya:
An annual glabrous herb of winter.
7. Striga:
A root parasite of Pennisetum.
8. Lindenbergia:
A common perennial herb on old walls and soil.
Division of the family and chief genera:
Wettstein divided the family into 3 sub-families and 12 tribes:
A. Two posterior corolla teeth or upper lip cover lateral teeth in bud.
Sub-family 1. Verbascoideae (Pseudosolaneae):
All leaves usually alternate; 5 stamens often present. This includes 2 tribes e.g. Verbascum, Aptosimum.
Sub-family 2. Scrophularioideae (Antirrhinoideae):
Lower leaves at least opposite; the 5th stamen wanting or staminode. This includes 7 tribes.
B. Two posterior teeth or upper lip of corolla covered in bud by one or both of the lateral teeth.
Sub-family 3. Rhinanthoideae:
Corolla teeth all flat and divergent, or the upper erect. This includes 3 tribes.
Important Type of Scrophulariaceae:
Lindenbergia indica (Fig. 79.1):
Habit:
An annual herb.
Root:
Tap, branched.
Leaf:
Opposite, simple, petiolate, exstipulate, ovate, dentate, hairy, unicostate reticulate.
Inflorescence:
Solitary axillary.
Flower:
Bracteate, pedicellate, complete, hermaphrodite, zygomorphic, pentamerous, hypogynous.
Calyx:
Sepals 5, gamosepalous, campanulate, valvate, inferior.
Corolla:
Petals 5, bilipped, 2/3, upper with 2 lobes, lower of 3 -lobes, red throat, hairy, imbricate, inferior.
Androecium:
Stamens 4, didynamous, fifth posterior stamen reduced, polyandrous, epipetalous, anthers dithecous, dorsifixed, filaments filiform, introrse.
Gynoecium:
Bicarpellary, syncarpous, superior, bilocular, axile placentation, many ovules in each loculus, style simple, stigma bifid.
Floral formula:
