Liliaceae: Characters, Distribution and Types

In this article we will discuss about:- 1. Characters of Liliaceae 2. Distribution of Liliaceae 3. Economic Importance 4. Affinities 5. Important Types.

Characters of Liliaceae:

Herbs rarely shrubs, stem underground rhizome, corm or bulb; leaves alternate, flowers actinomorphic, trimerous, hypogynous, perianth 6 in two whorls of 3 each, free or fused; stamen 3+3, epiphyllous, antiphyllous; gynoecium tricarpellary, syncarpous, ovary superior, axile placentation, two to many ovules per loculus; fruit capsule or berry; seed endospermic.

A. Vegetative characters:

Habit:

Mostly herbs (Asphodelus), perennating by rhizome (Aloe), bulb (Lilium, Tulipa, Allium), tree (Dracena), climber (Asparagus, Smilax), xerophytic plants like Yucca, Aloe; cladodes in Asparagus and Ruscus.

Root:

Fibrous adventitious, sometimes tuberous (Asparagus).

Stem:

Herbaceous, or woody, solid or fistular, underground; aerial climbing or erect; underground stem may be corm, bulb or rhizome. In Ruscus and Asparagus aerial stems bear phylloclades (modified leaf-like branches), corm (Colchicum); secondary growth in Yucca. Dracaena, Aloe.

Leaves:

Alternate, opposite or whorled, radical and cauline, exstipulate, sessile or petiolate, sheathing leaf base; shape is variable scale-like (Asparagus), thick succulent and mucilaginous in Aloe, broad in Phormium tenax. In Smilax stipulate and stipules are modified into tendrils. Venation is usually parallel but reticulate in Smilax and Trillium.

B. Floral characters:

Inflorescence:

Variable-solitary (Tulipa, Fritillaria), panicled raceme (Asphodelus), cymose umbel (Allium, Smilax), solitary axillary (Gloriosa).

Flower:

Pedicellate, actinomorphic or zygomorphic (Lilium, Hemerocallis), hermaphrodite or unisexual in Smilax, Ruscus; hypogynous, complete or incomplete (in unisexual flowers), trimerous rarely 2 or 4-merous (Maianthemum, Paris).

Perianth:

6, in two words of three each, polyphyllous (Lilium, Tulipa) or gamophyllous (Aloe, Asparagus) and of various shapes; petaloid or sepaloid; imbricate in bud, usually valvate aestivation, perianth may be scarious or membranous.

Androecium:

Stamens 6 or 3 (Ruscus), 8 in Paris; polyandrous, epiphyllous, antiphyllous, filaments long, anthers versatile or basifixed, dithecous, introrse or extrorse. In Ruscus outer whorl of stamens is reduced to staminodes.

Gynoecium:

Tricarpellary, syncarpous, ovary superior or half inferior, trilocular or unilocular with two ovules, axile placentation, style simple; stigma trilobed or 3-parted.

Fruit:

A berry (Asparagus, Smilax), capsule (Asphodelus).

Seed:

Endospermic; endosperm horny or cartilagenous.

Pollination:

Entomophilous rarely self-pollination.

Floral formula:

Distribution of Liliaceae:

It is commonly called “Lily family”. It includes 250 genera and 4000 species, which are world wide in distribution. In India it is represented by 169 species.

Economic Importance of Liliaceae:

1. Food:

Allium cepa (Onion), Allium sativum (Garlic) and Asparagus are edible and used as food.

2. Medicinal:

Smilax, Aloe, Gloriosa, Veratrum, Colchicum, Scilla and Urginea yield useful drugs. Rat poison is obtained from Urginea and the bulbs of Scilla. Aloe vera yields “Aloin”. The roots of Asparagus (H. Satavaer) yields a tonic. From Colchicum, colchicine is obtained.

3. Fibres:

Yucca, Phormium tenax yield fibres of commerce.

4. Resin:

Dracaena and Xanthorrhoea yield resin. From the acrid resin of Xanthorrhoea sealing wax is prepared.

5. Ornamentals:

The common cultivated garden plants are Tulipa, Lilium, Gloriosa, Aloe, Ruscus, Dracaena, Asparagus, Yucca, Hemerocallis etc.

Primitive characters:

1. Perennial and arboreal habit in some genera (Aloe, Yucca).

2. Leaves simple and spirally arranged in most genera.

3. Solitary flowers in some genera.

4. Flowers hermaphrodite and actinomorphic.

5. Flowers are large and hypogynous.

6. Perianth polyphyllous in some genera (Asphodelus, Veratrum).

7. Seeds endospermic.

Advanced characters:

1. Many plants are herbaceous.

2. Leaves exstipulate, opposite or whorled in some genera.

3. Flowers are zygomorphic in some genera (Lilium, Hemerocallis).

4. Flowers unisexual (Ruscus, Smilax).

5. Perianth gamophyllous in many genera.

6. Stamens epiphyllous.

7. Reduction in the number of stamens to 3 (Ruscus).

8. Carpels 3 or 2 and syncarpous.

9. Axile placentation.

Affinities of Liliaceae:

The family has close affinity with Amaryllidaceae from which it can be distinguished by the presence of superior ovary, and absence of corona.

It is also close to Juncaceae as in both the seeds have albumen but differs from Juncaceae in petaloid perianth.

The family, on account of marked variabilities in cytological, embryological and anatomical structures, appears to be polyphyletic in origin. Its origin from Helobieae or its ancestor may be assumed from floral structures and helobial endosperm formation in some of the genera of Liliaceae as Petrosavia, Protolirion. The helobian origin is further supported by the flower construction of Helonias which is similar to the members of Juncaceae.

Liliaceae is regarded as a typical monocot family and represents the basic monocot stock from which many families have arisen.

Hutchinson has excluded many genera which are included by many botanists in the family Liliaceae. He has included Allium, Agapanthus in the family Amaryllidaceae of his order Amaryllidales; Yucca, Dracaena, Sanseuiera, Phormium in the family Agavaceae of his order Agavales; Xanthorrhoea in the family Xanthorrhoeaceae of his order Agavales. He has also included Smilax in the family Smilacaceae and Ruscus in Ruscaceae in his order Liliales.

Common plants of the family:

1. Allium:

Cultivated in winter for bulbs.

2. Aloe:

Shrubby xerophytic plant, wild on rocks with dull red flowers.

3. Asphodelus:

Common winter weed in wheat fields.

4. Asparagus:

A thorny climbing under-shrub with cladodes and fasiculated roots.

5. Colchicum (Meadow saffron):

Corm is very useful. It gives Colchicine.

6. Dracaena:

Tree with anomalous secondary growth in the stem.

7. Fritillaria:

Grown in garden as ornamental.

8. Gloriosa (Glory lily):

Climber with tips of leaves turned into tendrils.

9. Ruscus:

Flowers arise on the upper surface of phylloclades.

10. Smilax:

A climber with stipular tendrils and reticulate venation.

11. Tulipa:

Grown in garden as ornamentals.

Division of the family and chief genera:

Engler and Krause divided the family into 12 sub-families as follows:

Sub-family I. Melanthioideae:

Rhizome or bulb covered with scale leaves and with terminal inflorescence, e.g. Gloriosa, Colchicum.

Sub-family II. Herrerioideae:

Tubers with climbing stem, inflorescence small flowered racemes, e.g. Herreria.

Sub-family III. Asphodeloideae:

Rhizome with radical leaves, inflorescence a spike, e.g. Ashphodelus, Aloe.

Sub-family IV. Allioideae:

Bulb or short rhizome, cymose umbel, e.g. Allium, Agapanthus.

Sub-family V. Lilioideae:

Bulb, stem bearing one or more leaves, e.g. Lilium.

Sub-family VI. Scilloideae:

Bulb but stem leafless, e.g. Scilla.

Sub-family VII. Asparagoideae:

Rhizome subterranean, e.g. Asparagus.

Sub-family VIII. Dracaenoideae:

Stem erect with leafy crown, e.g. Yucca, Dracaena.

Sub-family IX. Ophiopogonoideae:

Short rhizome, e.g. Ophiopogon.

Sub-family X. Aletrioideae:

Short rhizome with arrow or lanceolate radical leaves e.g. Aletris.

Sub-family XI. Luzuriagoideae:

Shrubs or under-shrubs with erect or climbing twigs e.g. Luzuriaga.

Sub-family XII. Smilacoideae:

Climbing shrubs with netveined leaves, e.g. Smilax.

Important Types of Liliaceae:

1. Asphodelus tenuifolius (H. Paiz) (Fig. 107.1):

Habit:

An annual weed.

Root:

Adventitious, fibrous.

Stem:

Compressed, herbaceous, without nodes and internodes, smooth, greenish brown, aerial, peduncles are erect and fistular.

Leaves:

Radical, simple, cylindrical, green, pointed, smooth, apex acute, exstiuplate, sessile, sheathing leaf-base, parallel venation.

Inflorescence:

Panicled raceme, borne on branched leafless scape.

Flower:

Bracteate, pedicellate, complete, actinomorphic, hermaphrodite, hypogynous, trimerous.

Perianth:

Tepals 6 in two whorls of 3 each, large, petaloid, polyphyllous, sometimes slightly fused at the base, imbricate aestivation, inferior.

Androecium:

Stamens 6, epiphyllous, in two whorls of 3 each, polyandrous, anthers dithecous; dorsifixed or versatile inferior.

Gynoecium:

Tricarpellary, syncarpous, tilocular, axile placentation, 2 ovules per loculus, ovary superior, style slender, filiform, stigma trilobed, yellow.

Fruit:

Loculicidal capsule.

Floral formula:

2. Allium cepa (H. Paiz) (Fig. 107.2):

Habit:

An annual cultivated herb.

Root:

Adventitious fibrous.

Stem:

Underground tunicated bulb, extremely reduced to a conical disc like structure.

Leaves:

Radical, cylindrical, long, exstipulate, sessile, fleshy, sheathing leaf-base, hollow, multicostate parallel venation.

Inflorescence:

Monochasial cymes enclosed by 2 or 3 membranous bracts arranged in an umbellate fashion on an erect leafless scape.

Flower:

Pedicellate, small, hermaphrodite, hypogynous, complete, actinomorphic, trimerous, white, bracteate.

Perianth:

Tepals 6, in 2 whorls of 3 each, gamophyllous, united at the base, white, inferior.

Androecium:

Stamens 6, polyandrous, in two whorls of 3 each, epiphyllous, filament narrow, dilated at the base, anthers dithecous, dorsifixed.

Gynoecium:

Tricarpellary, syncarpous, ovary superior, trilocular, axile placentation, 2 ovules per loculus; style short filiform, stigma minute.

Floral formula: