Taxonomy Of Angiosperms By Pandey & Misra (2008)- Details
PLANT TAXONOMY 2E By SHARMA (2011)- Details
RANUNCULACEAE WEEK- MAY 02-08, 2011: This is my privilege to discuss family of the week with a group where
putting up things is always learning rather than dictating anything. I am hopeful to get enriched by valuable inputs from all the members of the group. Here, to start with, general points to keep in mind about the family Ranunculaceae are being discussed:
Ranunculaceae Jussieu (The Buttercup Family or The Crowfoot Family)
A highly variable family of about 1900 species of dicotyledonous plants that includes the buttercups, monkshoods, anemones, clematis, delphiniums and hellebores, distributed mainly in North temperate and
arctic regions. Most members of the family are at least slightly poisonous.
In India, this family is represented by 20 genera and about 150 species, mostly confined to mountainous regions.
Vegetative characters: Nearly all the members of the family are herbaceous, except Clematis the species of which are woody, generally climbing. Majority of the Ranunculaceans are perennials, but for a few like Nigella being annuals. Almost all of them love terrestrial, moist localities but few species of Ranunculus are truly aquatic (e.g. R. aquatilis).
Rootstock sometimes becomes tuberous with age in perennials. Leaves usually alternate (opposite in Clematis) with sheathing bases and often very much divided, usually exstipulate but stipulate in Trollius, Caltha, Thalictrum (leaf base is broadened into stipule-like lobes) and Ranunculus.
Leaf shape variable, usually leaves are simple and palmately lobed (as in Ranunculus) or decompound (like Delphinium), entire (Caltha) and pinnately compound (Clematis). Aquatic species of Ranunculus show heterophylly with submerged leaves finely dissected. Leaves are modified into tendrils in Clematis aphylla.
Inflorescence and Flowers: Inflorescence, though quite variable, is more often a branched cyme. In Anemone, Nigella and Eranthis a single terminal flower is produced. Elongated racemes can be seen as in Delphinium, Aconitum and also much branched panicles can be found as in Clematis and Thalictrum. In Nigella and Anemone, there is sometimes an involucre of green leaves below the flower, usually alternating with the calyx.
The floral parts are free and spirally arranged upon a more or less elongated receptacle, and their number varies considerably from one genus to the other. Flowers are mostly bracteate, actinomorphic (zygomorphic in Delphinium and Aconitum), hermaphrodite (except in some species of Thalictrum), pentamerous and hypogynous.
The perianth may be distinguishable into calyx and corolla or it may be undifferentiated. The innermost perianth segments often bear conspicuous nectaries or very small and reduced nectariferous sacs or scales.
The calyx consists of five to eight sepals which are distinct, usually caducous, with imbricate or valvate aestivation. In Delphinium and Aconitum, the sepals are petaloid and the posterior sepal is spurred.
The corolla is usually of five, free, symmetrical (Ranunculus) or irregular (Delphinium, Aconitum) petals. In Delphinium, the posterior pair of petals forms spur which projects into spur of the petal. In Aquilegia all the five petals form a spur at the base. Ranunculus has a pocket-like nectary at the base of each petal. In Caltha, Clematis
and Anemone, the petals are completely absent and sepals become petaloid.
The androecium usually of many, polyandrous and spirally arranged stamens (in some genera like Helleborus, Nigella and Aquilegia the are arranged in definite rings). Anthers are adnate, dithecous, extrorse and dehiscing longitudinally. The filaments are beautifully coloured in some species of Thalictrum. Flowers are usually protandrous and the stamens after dehiscence bend outwards from centre.
The gynoecium is usually of numerous free carpels arranged spirally on a distinct thalamus, few taxa, of course, have a definite number of carpels. Aquilegia has five carpels and Delphinium has 1-3 carpels. In
few others like Actaea and Cimicifuga, carpels are reduced to one . Not only in number, gynoecium shows variation in cohesion also. In some species of Helleborus, the carpels are connate at the base, whereas in Nigella the five carpels are completely united.
The ovary is superior, unilocular with one to many ovules. The palcentation may be basal (Ranunculus), apical (Clematis) or marginal (Delphinium) and in Nigella, where gynoecium is syncarpous, ovary is pentalocular with axile placerntation.
Fruit usually a group of achenes or follicles (capsule in Nigella, in Actaea). Seeds with small embryo and oily endosperm.
Well-known representatives of the family include: Ranunculus (Buttercup), Clematis (Virgins-bower, Traveller’s joy), Anemone (Wind Flower), Delphinium (Larkspur), Aconitum (Aconite), Paeonia (Peony), Caltha (Marsh marigold), Aquilegia (Columbine), Nigella (Love-in-a–mist), (Hellebore) etc.
I hope to see some of my “favorites” of the family from the group in the coming week. The family is poorly represented in our area, and I apologize that I won’t be able to upload many members.
Thanks and Happy Ranunculaceae Week.
Ranunculaceae Fortnight: Introduction : 6 posts by 5 authors.
FAMILY OF THE WEEK: RANUNCULACEAE
In India there are 20 genera and 154 species mostly confined to mountainous region.
They are mainly annual or perennial herbs but some are climbers such as Clematis. Some are aquatic herbs. The perennial species usually develop rhizomes and tuberous roots. The vascular bundles in the stem of some genera are not arranged in a ring but are somewhat irregular, recalling the arrangement of monocots.
The leaves are radical or alternate or opposite as in Clematis. Stipules are absent but they often have sheathing bases. Generally they are simple and palmately lobed or divided but they are entire in Caltha, pinnately compound in Clematis and decompounds in Thalicrtum. Aquatic species show heterophylly with submerged leaves finely dissected.
Inflorescence and flowers:
The Inflorescence is variable. Most of the genera show typically determinate Inflorescence. The flowers are solitary terminal in Anemone and Nigella. They form long racemes in Delphinium and Acotinum and much branched panicles in Clematis and Thalictrum. The flowers are generally bisexual, mostly actinomorphic. The flower parts are arranged spirally on an elongated receptacle. The sepals are 5-8, distinct, imbricate or valvate, usually deciduous. The petals are usually five free symmetrical or irregular. The stamens are many polyandrous and spirally arranged. The anthers are adnate dithecous, extrorse and dehiscing longitudinally. The gynoecium is usually of numerous free carpels arranged spirally on a distinct thalamus. The style and stigma are one.
Fruits and seeds:
The fruit is usually a group of few to many seeded follicles or a group of one seeded achenes. InClematis the achenes have long persistent feathery styles. The seed has a copious endosperm and a minute straight embryo.
Pollination and dispersal:
The flowers are protandrous and are adapted for insect pollination. The dispersal is by wind in many species. Some are disseminated by animals and birds.
Thalictrum (Meadow- rue)
Clematis ( Virgins- bower)
Anemone (Wind flower)
Nigella sativa (Black fennel,Kala jeera)
Caltha (Marsh Marigold)
Well done … Having given the broad characteristics of the family Ranunculaceae, you have rendered a yeoman’s services for the young upcoming Botanists. It is very useful.
That was just a brief compilation(Second part) from a non botanist me.
That is part of a blog I used to write in 2008 earlier for my study of botany as hobby.
The first part is written by …
We expect similar good informative comments from experts like you to the posts from our members as you are always giving. Thanks again.
Thank you very much …, this was a much needed step, I was somehow not able to interact this week…