In this article we will discuss about:- 1. Characters of Papaveraceae 2. Distribution 3. Economic Importance 4. Affinities 5. Important Types.
Characters of Papaveraceae:
Leaves alternate, simple, lobed, latex present, flower solitary, actinomorphic, hypogynous. Sepals two or three, caducous, petals 2 or 3, stamens numerous, free, sometimes reduced to four or two, anthers extrorse, carpels two or many, parietal placentation, fruit capsule.
A. Vegetative characters:
The members of this family are mostly annual or perennial herbs, shrubs (Dendromedon), rarely trees (Bocconia). The plants have latex which may be white or yellowish in colour.
Tap root and branched.
Erect, herbaceous, branched, cylindrical and woody in Bocconia.
Radical simple, alternate, exstipulate, dissected (Fumaria, Chelidonium).
B. Floral characters:
Solitary terminal (Papaver), axillary raceme and panicles (Bocconia).
Ebracteate, pedicellate, actinomorphic, complete, di- or trimerous, hypogynous rarely perigynous (Eschscholtzia).
Sepals 2 or 3, polysepalous, caducous and inferior.
Petals 2 + 2 or 3 + 3 or more, rolled or crumpled in bud, polypetalous, brightly coloured.
Stamens four or indefinite (Papaver, Argemone), polyandrous, filament slender; anthers dithecous and extrorse.
Carpels two or more syncarpous; ovary superior (slightly perigynous in Eschscholtzia), unilocular, parietal placentation; ovules numerous, stigma sessile, persistent forming a crown in the fruit.
Capsule, dehiscence by valves or pores, rarely nut.
Distribution of Papaveraceae:
The family is commonly known as poppy family. It consists of 28 genera and 700 species (Rendle) out of which 45 species are found in India. The members of this family are well distributed in the northern extra-tropical and temperate countries. Some are also found as weeds throughout the world.
Economic Importance of Papaveraceae:
Seeds of Papaver somniferum are used as condiment and food of people.
Opium is obtained from the latex of the unripe fruits of Papaver somniferum. Opium is supposed to contain some 25 alkaloids; the better known are morphine, codeine, narcotine etc. Opium is a powerful narcotic and is used for addiction.
Medicinally the alkaloid are quite valuable. Morphine is widely used to relieve pain as it acts on the sensory cells of the brain and the patient is lulled into an artificial sleep. Codeine is used in cough syrups as a mild sedative.
The roots of Sanguinaria canadensis produce bloodroot and are used in rheumatism and dyspepsia. The seeds of Argemone produce an oil which is used for adulterating mustard oil. This oil is of course harmful to man.
Papaver rhoeas, Eschscholtzia, Sanguinaria are cultivated as ornamental garden plants.
Affinities of Papaveraceae:
The family Papaveraceae stands very close to Ranunculaceae and Nymphaeaceae. The morphological structure of flowers of Platystemon establish a link between Papaveraceae and Nymphaeceae.
A.C. Joshi observed gynophore formation in some abnormal flowers of Argemone which may suggests that Papaveraceae has close affinity with Capparidaceae.
The pod shaped ovary with the parietal placentation are characters of Papaveraceae shared with the Brassicaceae and Capparidaceae. But the seeds of Papaveraceae are albuminous.
Some authors have treated Fumariaceae as a sub-family of Papaveraceae while Hutchinson recognised it as a separate family.
1. Presence of shrub and tree (Bocconia).
2. Leaves simple and alternate.
3. Flowers hermaphrodite, hypogynous and actinomorphic.
4. Calyx and corolla free.
5. Stamens numerous, free and produce abundant pollen.
6. Carpels many and loosely united (Platystemon).
7. Ovules anatropous and many on each placentum.
1. Plants are mainly herbs.
2. Leaves are deeply incised (Argemone).
3. Flower perigynous (Eschscholtzia).
4. Calyx gamosepalous (Echscholtzia).
5. Gynoecium syncarpous.
Common plants of the family:
1. Argemone Mexicana:
A prickly herb that grows wild on roadside with yellow flowers.
2. Papaver somniferum:
A source of opium.
A tree with apetalous flowers and arillate seeds.
It has a thick rhizome, giving off annually one leaf and one flowered scape.
5. Meconopsis aculeate:
A prickly shrub with blue purple flowers.
Division of the family and chief genera:
The family Papaveraceae has been divided into three sub-families viz.:
Latex present; flower regular; petals neither spurred nor saccate; stamens indefinite, free; carpels 2 to many. Papaver, Argemone.
Latex absent; flower regular; petals trilobed; stamens four, carpels two; fruit a long pod. Hypecoum, Pteridophyllum.
Oil sacs present; flower irregular; petals saccate or spurred; stamens two, tripartite, carpels two.
The sub-family Fumarioideae has been considered as a separate family Fumariaceae by Bentham and Hooker and Lawrence.
Flowers regular without a spurred petal; stamens numerous and free; carpels two to several. De Candolle considered that the flowers were typically tetramerous but Celakovsky considered them to be dimerous.
Sepals two merely protective in function and highly caducous in Papaver. Argemone has three sepals; in Eschscholtzia the sepals are elevated on a cuplike projection of the floral axis so that the flower becomes perigynous; further the sepals are fused with each other and when the petals grow they are pushed off like a cap.
Petals are twice as many as the sepals; thus in Papaver and Eschscholtzia they are four (2+2); in Argemone and Platystemon (3+3) but in Macleyaya (China and Japan) and Bocconia (S. America) the petals are totally absent.
The stamens remarkably variable in number and arrangement. Development studies have revealed that each whorl has two (or multiple of two) in dimerous flowers and three (or multiple of three) in trimerous flowers. The total number of stamens are numerous (Papaver, Argemone, Platystemon, Meconopsis etc.).
The total number of carpels is variable; in Papaver there are 4-16 carpels; in Argemone 4-6 carpels; in Platystemon numerous carpels and the ovary also becomes multilocular. In Chelidonium there are only two carpels.
The sub-family is characterized by dimerous and regular flowers. Stamens are only four in number and one opposite each petal. The ovary is bicarpellary and its single chamber becomes divided by a septum developing in the fruiting stage. Hypecoum is the representative genus.
Important Types of Papaveraceae:
Papaver rhoeas Linn (Fig. 29.4) (Garden Puppy):
An annual ornamental herb.
Tap, branched and annual.
Erect, herbaceous, cylindrical, fistular, branched, green, and hairy.
Alternate, exstipulate, simple, sessile, leaf-base sheathing, apex acute, margin hairy, unicostate reticulate venation.
Ebracteate, pedicellate, complete, hermaphordite, actinomorphic, hypogynous, land drooping.
Sepals 2, polysepalous, caducous, hairy, inferior.
Petals 4, polypetalous, caducous, hairy, imbricate aestivation, inferior.
Stamens indefinite arranged in 2-3 whorls, polyandrous, basifixed, dithecous and extrorse.
Polycarpellary, syncarpous, superior, unilocular, parietal placentation, ovules many, persistent stigma with sessile stigmatic rays.
2. Argemone mexicana. Linn. (Fig. 29.6) (Prickly Poppy):
Erect, annual herb.
Herbaceous, erect, cylindrical, solid, spiny, sparingly branched with yellow latex.
Radical, cauline, simple, exstipulate, sessile, spiny, green, alternate and unicostate reticulate venation.
Ebracteate, pedicellate, complete, hermaphrodite, actinomorphic, trimerous, hypogynous.
Sepals 3, polysepalous, caducous, prickly, twisted aestivation.
Petals 6, in two whorls of 3 each, polypetalous, yellow.
Stamens indefinite, polyandrous, arranged in several whorls, filament long, anthers basifixed, dithecous, extrorse.
Pentacarpellary, syncarpous, ovary superior, unilocular, parietal placentation, many ovules on each placentum, stigma as many as carpels, red, style absent.