Wednesday, 13 August 2008
FAMILY OF THE WEEK:LILIACEAE
A large family widely distributed in most parts of the world. In India there are 35 genera and 189 species majority of them occurring chiefly in the Himalayas.
They are mostly perennial herbs persisting by means of a sympodial rhizome or by a bulb. Sometimes as in Asparagus they are annual herbs.
Yucca, Dracaena and Aloe are shrubby or treelike with a perennial aerial stem growing in thickness by successive rings of meristem. The species of Smilax and Heterosmilax are woody climbers with often prickly stem. They climb with the help of stipular tendrils which arise from the leaf sheath.
The species of Asparagus are rhizomatous plants with herbaceous or woody erect straggling or climbing stems. The leaves are reduced to tiny scales and the ultimate branches become needle like or flattened. These cladodes take up the function of the leaves. Gloriosa is a perennial tuberous herb with a climbing stem. The climbing is affected by the leaf tip which elongates to form a spiral.
The leaves are basal(Allium,Lilium) or cauline. They are usually alternate, rarely opposite(Gloriosa) or whorled. They vary in shape from linear to broadly ovate. They are fleshy in Aloe with a large water storing tissue. The venation is parallel but in Smilax the leaves are net-veined. In Asparagus the leaves are reduced to minute scales.
Inflorescence and flowers:
Flowers are born in simple or branched racemes. They form apparent umbel in Alium subtended by spathe like bracts. In Yucca The inflorescence is a huge terminal panicle. Sometimes the flowers are solitary terminal as in Lilium.
The flowers are often showy,bisexual, actinomorphic or slightly zygomorphic, usually trimerous and hypogynous.
The perianth is of six tepals arranged in two whorls.They are free or united. The perianth segments are usually petalloid and the two whorls are generally undifferentiated.
Androecium is usually of six stamens in two whorls.The filaments are free or variably connate. The anthers are basifixed, dithecous,introrse or extrorse.
The gynoecium is tricarpellary and syncarpous with a superior and trilocular ovary. The style is usually one with three distinct stigmas. Usually the ovary has three septal nectaries.
The fruit is usually a loculicidal or septicidal capsule or sometimes a berry as in Smilax and polygonatum.
Pollination: Showy fragrant flowers and nectaries are for insect pollination.
The family provides several food,drug and fibre plants and many genera are important as ornamentals.
Allium sativum(Garlic, Lasun)
Asparagus officinalis (Garden asparagus) Fleshy shoots as vegetables.
Asparagus plumosus : several varieties cultivated as ornamentals.
Aloe vera (Korphad)
Scilla hyacinthina (South Indian Squill)
Gloriosa superba (Glory lily,Kal-lawi)
Iphigenia indica :Flowers yield red dye.
Lilium(Lily) They rank high among bulbous ornamentals.L.giganteum;L.candidum.
Yucca Tulipa (Tulip)
Posted by SATISFIED at 18:36