Salient features, floral diversity, diversity of families and phylogeny of order Ranales

Salient features, floral diversity, diversity of families and phylogeny of order
Ranales

1. Salient features, floral diversity, diversity of families and phylogeny of order Ranales Subheadings - (i) Salient features of Ranales (ii) Floral diversity in Ranales (iii) Diversity of families in Ranales (iv) Phylogeny of order Ranales

2. Ranales : Salient features, floral diversity, diversity of families and phylogeny Dr . Praveen Mohil Assistant Professor Department of Botany University of Rajasthan Jaipur-302004

3. Why this Taxon is so special ? Ans - Ranales is a natural taxon. It is characterized by the parts typically spirally arranged (cyclic in advance member), numerous, distinct, the perianth often not differentiated into calyx and corolla. Gynoecium is apocarpous and multicarpellate (i.e., composed of many unilocular unicarpellte pistils).

4. Introduction Historically the term Ranales was used to include the Ranunculaceae and related families, as described by Bentham and Hooker. This became replaced with Ranunculales by Melchior in 1964.

5. (i) Salient features of Ranales = Ranunculales Salient features: Flower Structure: Flowers in the Ranunculales order are often characterized by simple floral parts. They typically have numerous stamens and several carpels . The petals and sepals may not be clearly differentiated, and in some species, sepals can be petal-like or brightly colored. Inflorescence: Ranunculales species exhibit various types of inflorescences, including solitary flowers, racemes, panicles, cymes, or other arrangements. The inflorescence structure can vary greatly among families within the order. Leaves: Leaves in the Ranunculales order are usually alternate and can range from simple to compound. Leaf shapes vary widely among species, from lobed to palmately or pinnately compound.

6. (ii) Floral diversity in Ranales (ii) Floral diversity in Ranales key aspects of floral diversity - Flower Structure: Flowers in the Ranunculales order exhibit considerable variation in structure. While there is no universal blueprint , many species have radially symmetrical flowers with simple floral parts. However, the degree of differentiation of these parts can vary greatly among different families and genera. Sepals and Petals: In some species within the order, the sepals and petals are not clearly differentiated, and instead, the perianth consists of petaloid sepals or petal-like structures called tepals . In other cases, both sepals and petals are present and may be similar or different in appearance. Stamens and Carpels: Ranunculales species often have numerous stamens, sometimes in multiple whorls, surrounding several separate or fused carpels. This arrangement can contribute to the showiness and complexity of the flower.

7. (ii) Floral diversity in Ranales Inflorescence Types : it exhibit diverse inflorescence architectures , including solitary flowers, racemes, panicles, cymes, and umbels. The inflorescence type can vary not only between families but also among genera and species within a family. Color and Ornamentation : Flowers in the Ranunculales order come in a variety of colors , including white, yellow, red, blue, and purple. Some species have elaborate floral structures with intricate patterns or markings, while others have simple, unadorned blooms. Specialized Floral Adaptations : Certain species within the Ranunculales order have evolved specialized floral adaptations to attract specific pollinators or to ensure successful pollination and reproduction . These adaptations can include nectar spurs, specialized floral shapes, or mechanisms for pollen dispersal.

8. (iii) Diversity of families in Ranales It encompasses several families, each with its own unique characteristics and members. Engler and Prantl (1887–1915) have included 19 families namely Nymphaeaceae , Ceratophyllaceae , Cercidiphyllaceae , Trochodendraceae , Ranunculaceae , Lardizabalaceae , Berberidaceae , Menispermaceae , Magnoliaceae , Calycanthaceae , Lactoridaceae , Annonaceae , Eupomatiaceae , Myristicaceae , Monimiaceae , Gomortegaceae , Lauraceae , Hanandiaceae and Himantandraceae in 21st order of subclass Archichlamydeae . In the Bentham and Hooker system (1862-1883), the Ranales were the first cohort of the Thalamiflorae with eight families: i. Ranunculaceæ , ii. Dilleniaceæ , iii. Calycanthaceæ , iv. Magnoliaceæ , v. Anonaceæ [sic], vi. Menispermaceæ , vii. Berberideæ & viii. Nymphæaceæ  

9. (iii) Diversity of families in Ranales Bessey (1915) made it a much larger entity within the Strobiloideae with 24 families. Later, Hutchinson (1959) has included 07 families namely, Paeoniaceae , Helleboraceae , Ranunculaceae , Nymphaeaceae , Podophyllaceae , Ceratophyllaceae and Cabombaceae in 55th order of II phylum Herbaceae . Melchior (1964) preferred the term Ranunculales to include the Ranunculaceae within Archychlamydeae , the term which is still in use including seven families but little overlap with Hutchinson. The Cronquist system (1981) also recognised the order, but placed it in the subclass Magnoliidae , in class Magnoliopsida [= dicotyledons ]. It used this circumscription: order Ranunculales - 1. Ranunculaceae , 2. Circaeasteraceae , 3. Berberidaceae , 4.Sargentodoxaceae, 5. Lardizabalaceae , 6.Menispermaceae, 7. Coriariaceae & 8. Sabiaceae The current APG system uses Ranunculales in the Eudicot clade with seven families.    

10. (iv) Phylogeny of order Ranales - (iv) Phylogeny of order Ranales - Ranales have been considered as the most primitive due to the absence of vessels in large number of families like Alismataceae . Magnoliaceae , Winteraceae etc. Peculiar floral morphology, anatomy as well as binucleate pollen at the time of release from the microsporangium in several families like Magnoliaceae , Ranunculaceae , Winteraceae etc. Ranales ( Magnoliales ) are considered, as the most primitive order according to Arber and Parkin (1907), Bessey (1915), Hutchinson (1959, 1969), Takhtajan (1980) and Cronquist (1988). But Engler and his associates considered that the Ranales are advanced and kept them in the middle of the Dicotyledons . Benthum and Hooker (1862-83) kept this order at the starting of classification. Ranales of Benthum and Hooker comprises eight families. It is characterized by numerous floral parts, especially stamens and carpels; floral parts arranged in spiral, cyclic or hemicyclic manner with hypogynous flower.

11. (iv) Phylogeny of order Ranales - Engler and Prantl (1938), have included 19 families in 21st order of subclass Archichlamydeae . Hutchinson (1959) has included seven families in 55th order of II phylum Herbaceae . Hutchinson (1959, 1969) kept the woody members in Lignosae and herbaceous members in Herbaceae in 7 orders. Magnoliales , Annonales , Laurales , Dilleniales and Rosales under Lignosae while Ranales and Berberidales under Herbaceae . Engler and Prantl (1897-1915) kept all these families in his order Ranales except Dilleniaceae , which was kept in the order Parietales . Cronquist (1988) kept these families in 7 orders in three subclasses. Magnoliales , Laurales , Illiciales , Nymphaeales and Ranunculales ( Magnolidae ), Dilleniales ( Dillenidae ), and Trochodendrales ( Hamamelidae ). Takhtajan (1980) kept them in orders in four subclasses Magnolidae : Magnoliales , Illiciales , Laurales , Nymphaeales , Nelumbonales Ranunculidae : Ranunculales Hamamelidae : Trochodendrales Dillenidae : Dilleniales , Paeoniales

12. Phylogeny of ranales in APG system The term " Ranales " is an older classification and not used in the APG system. Instead, the families that were historically grouped under " Ranales " are now dispersed among several orders within the clade called Eudicots , particularly within the basal groups of Eudicots . Here's a summary of how these families are placed in the APG IV system: APG IV System Classification Order Ranunculales : Ranunculaceae , Berberidaceae , Menispermaceae , Papaveraceae , Lardizabalaceae , Circaeasteraceae , Eupteleaceae Order Proteales : Platanaceae , Nelumbonaceae , Proteaceae Order Buxales : Buxaceae , Haptanthaceae Within the Eudicots , the Ranunculales order is considered one of the earliest diverging groups, often referred to as "basal eudicots ." This implies that the Ranunculales diverged early from the lineage that led to the core eudicots , which comprise the majority of eudicot diversity.  

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