Learn about the comparison among Bentham and Hooker, Engler and Prantl, and Hutchinson systems of plant classification.
Comparison # Bentham and Hooker:
1. It is a natural system and mostly used for practical purposes.
2. It is based on A.P de Candolle’s system (1818).
3. Classification is based on single and mostly artificial characters; so closely allied families are separated widely.
4. Flowering plants have been divided into 202 families.
5. Dicots are kept before Monocots.
6. Gymnosperms are placed in between Dicots and Monocots.
7. Dicots are divided into three sub-groups : Polypetalae; Gam- opetalae; Monochlamydae.
8. Dicots are further divided into Series and Cohorts.
9. Monocots divided further into series and orders.
10. Monocots start with the Micro- spermae and end with Glum-aceae.
11. Bentham and Hooker began with families having pentamerous flowers which were supposed to be primitive and ended in Monochlamydeae having flowers with one whorl of perianth or perianth altogether absent.
12. Important publication Genera plantarum (1862-1883)
13. It deals with the classification of seed plants.
14. No reference is drawn regarding the evolution of angiosperms.
15. Dicotyledons begin with Ranales. This system is based on the dogma of fixity of species. Differences are more emphasised than resemblances in recognising seveal large artificial groups like Monochlamydeae.
16. Polypetalae is subdivided into 3 series: Thalamiflorae, Disci- florae & Calyciflorae. Polypetalae has 15 orders, which start with Ranales and ends with Umbellales. The first family is Ranunculaceae and last is Cornaceae.
17. Gamopetalae is subdivided into 3 series: Heteromerae and Bicarpellatae. It has 10 orders; starts with Rubiales and ends with Lamiales. The first family is Caprifoliaceae and the last one Plantaginaceae.
18. The family Curcurbitaceae showing gamopetalous condition is placed in the order Passiflorales almost at the flag end of Polypetalae.
19. The evolved family Compositae is placed in the beginning of Gamopetalae under Asterales.
20. The most advanced family Orchidaceae is placed at the beginning in the series Microspermae.
21. Gramineae is considered as the most advanced family; placed at the end of monocots under the series Glumaceae.
22. Many closely related families were kept apart, and unrelated distant families were put together; for example in dicotyledons the family Euphor- biaceae is placed under Monochlamydeae though it is related to Malvaceae of the Polypetalae; in monocotyledons the primitive family Hydro- chitaceae and the highly evolved family Orchidaceae are placed together on the basis of seed characters only, similarly closely allied families Liliaceae and Amaryllidaceae are placed apart from each other.
23. Defect with this system is the retention in Monochlamydeae a number of orders which show affinities with biseriate perianth. Among Monocots more emphasis has been given to relative position of ovary and the characters of the perianth in determining the affinities.
Comparison # Engler and Prantl:
1. It is a more or less phylogenetic and proposed after the theory of descent.
2. It is mainly based on Eicher’s system with the notion that the absence of perianth is a primitive character.
3. Classification is based on well-defined characters.
4. Flowering plants have been divided into 280 families.
5. Monocots are kept before Dicots.
6. Gymnosperms are placed separate from Dicots and Monocots.
7. Dicots are divided into two sub-groups: Archichlamydeae; Metachlamydeae (Sympetalae).
8. Dicots are not further divided.
9. Monocots are not further divided.
10. Monocots start with the order Pandanales and end with Microspermae.
11. The families are arranged according to increasing complexity of flower. Primitive forms are those having bract like perianth or naked flowers.
12. Important publication Die naturlichen Pflangen families (1887-1915).
13. It deals with the classification of the entire plant kingdom from algae to angiospermae.
14. They believe that angiosperms are evolved in polyphyletic manner from hypothetical gymnosperms (protoangiosperms) like Coniferales.
15. In dicotylendons, Amentiferae (Casuarinaceae, Piperaceae, Salicaceae etc.) are regarded as primitive and are placed before families such as Magnoliaceae, Ranunculaceae etc.
16. Archichlamydeae is subdivided into 31 orders; starting with Verticillatae and ends with Umbelliflorae. The first family is Casuarinaceae and the last one Cornaceae.
17. Sympetalae is subdivided into 11 orders; start with Dispensiales and ends with Campanulatae. The first family is Diapensiaceae and the last one Compositae.
18. Cucurbitacae has been elevated to the rank of order Cucurbitales and placed at the end of Sympetalae.
19. Compositae is palced at the end of Dicotyledonae under the last order Campanulatae of Sympetalae.
20. Orchidaceae is regarded as the most advanced family. The family is placed at the end of Monocots under the order Microspermae.
21. Gramineae is not given proper place under fourth order Glumiflorae of Monocots in between Helobiales and Princeps.
22. On the assumption that in flowering plants the absence of perianth is a primitive features; hence families having perianthless and unisexual flowers are regarded as primitive and are placed before the families having perianthed and bisexual flowers.
23. Defect with this system is that Amentiferae are being regarded as most primitive and precede such petaliferous families as Ranunculaceae and Mango- liaceae. Amentiferae is not only an artificial assemblage of several families, but they are probably a reduced rather than a primitive group as indicated in Engler’s system.
Other defects are his acceptance of dichlamydeous flowers as being derived from monochlamydeous ones; derivation of parietal placentation from axile one; free-central from parietal and his supposition of most of the simple unisexual flowers as primitive. Precedence of Monocots over Dicots.
Comparison # Hutchinson:
1. It is phylogenetic and more close to Bentham and Hooker’s system.
2. It is based on the assumption that the plants with sepals and petals are primitive.
3. Classification is based on definite characters.
4. Flowering plants have been divided into 411 families are recognised.
5. Dicots are kept before Monocots.
6. Gymnosperms are placed separate from Dicots and Monocots.
7. Same as in Engler & Prantl’s system.
8. Dicots are not further divided.
9. Monocots divided further into – Calyciferae. Corolliferae and Glumiflorae.
10. Monocots start with order Butomales and end with Graminales.
11. The primitive polvpetalous forms diverged from the very beginning along two separate lines.
12. Important publication Families of Flowering Plants (1926-1959).
13. It deals with the classification of flowering plants.
14. The evolution of angiosperms is monophyletic from hypothetical gymnosperms like Bennetti- tales.
15. In this system resemblances are emphasised than differences. Lignosae line (tree-like habit) starts with Magnoliaceae and Herbaceae (herbaceous habit) starts with Ranales.
16. Lignosae is divided into 54 orders; starts with Magnoliales and ends with Verbenales. The first family is Magnoliaceae and the last one Verenaceae.
17. Herbaceae is divided into 28 orders; starts with Ranales and ends with Lamiales. The first family is Ranunculaceae and the last one Labiatae.
18. Cucurbitaceae has been placed in Lignosae under Cucurbitales.
19. Compositae is placed under Herbaceae under the order (2nd one) Asterales.
20. Orchidaceae is given a proper position as the last family of Corolliferae.
21. Gramineae is given the highest place as the last family under Glumiflorae.
22. On the assumption that plants with sepals and petals associated with other primitive floral and anatomical characters are more ancient phylogenetically than plants with sepals and petals free floral parts are regarded as primitive and connate parts as more recent.
The Consideration of the phyletic lines viz., Lignosae and Herbaceae in his recent system a defect of the classification which is responsible for the undue fragmentation of the families.
23. Hutchinson’s fundamental principle that Dicots are evolved in two directions, one from herbaceous Ranales and other from woody Magnoliales has not been adopted by many. Other drawback is the insistence on a monophyletic origin from the seed plants in general and the angiosperms in particular.