In this article we will discuss about:- 1. General Features of the Liliaceae 2. Floral Range in the Liliaceae 3. Divisions 4. Position and Affinity 5. Number and Distribution 6. Commonly Occurring Plants 7. Economic Aspects.
General Features of the Liliaceae:
Habit – Perennial herbs with a bulbous or rhizomatous stem, sometimes climbing or arborescent.
Leaves – Cauline or radical, alternate or whorled, mostly parallel veined.
Inflorescence – Racemose, sometimes cymose.
Flowers – Bisexual, regular, hypogynous; bracts small, scarious or spathaoeous.
Perianth – Segments 6, in 2 whorls, sepaloid or petaloid. free or united.
Androecium – Stamens 6, in 2 series, free; anthers introrse or extrorse.
Gynoecium – Carpels 3, united; ovary superior, trilocular ovules 2 or more in each loculus; placentation axile.
Fruit – Berry or capsule.
Seeds – Embryo small; endosperm fleshy, horny or cartilaginous.
Floral Range in the Liliaceae:
In the Liliaceae, departure from the normal type of floral structure is rare. The flowers may be unisexual, as in Lomandra, Ruscus, Smilax and other genera. The flowers are also zygomorphic, e.g., Gilliesia, Haworthia and Hemerocallis. The flowers may be tetramerous or pblymerous in Paris, The ovary is semi-inferior in Mondo. There are 3 stamens in the male flower of Ruscus, one whorl being suppressed.
Divisions of the Liliaceae:
The Liliaceae is divided into 11 subfamilies:
Subfamily I. Aletridoideae:
Radical leaves lanceolate and small. Ovary semi-inferior. Fruit a capsule. Example- Aletris.
Subfamily II. Allioideae:
Underground stem mostly a bulb. Inflorescence an umbellate cyme, always enclosed by a membranous spathe. Example- Allium, Gilliesia, etc.
Subfamily III. Asparagoideae:
Underground stem a rhizome and aerial stem with leaves. Fruit a berry. Examples- Asparagus, Paris, etc.
Subfamily IV. Asphodeloideae:
Underground stem mostly a rhizome from which a leafless scape arises. Examples- Asphodelus, Hemerocallis, etc.
Subfamily V. Dracaenoideae:
Mostly arboreal; stem leafy; bulbs absent. Fruit a berry or capsule. Examples- Dracaena, Yucca, etc.
Subfamily VI. Herrerioideae:
Underground stem tuberous from which a climbing aerial stem arises. Fruit a capsule. Example- Herreria.
Subfamily VII. Lilioideae:
Underground stem a bulb: aerial stem scape-like, leafy; raphides present. Examples- Lilium, Lloydia, etc.
Subfamily VIII. Melanthioideae:
Short rhizome- or bulb-bearing plants. Inflorescence terminal. Fruit a capsule. Examples- Gloriosa, Tofieldia, etc.
Subfamily IX. Mondoideae:
Radical leaves linear. Ovary semi-inferior. Fruit a berry or capsule. Examples- Mondo, Peliosanthes, etc.
Subfamily X. Scilloideae:
Herbs with scaly leaves, bearing bulbs: aerial stem scape-like, leafy; raphides absent. Fruit a capsule. Examples- Scilla, Urginea, etc.
Subfamily XI. Smilacoideae:
Climbing or erect plants; aerial stems leafy. Fruit a berry. Examples- Heterosmilax, Smilax, etc.
Position and Affinity of the Liliaceae:
Bentham-Hooker included the Liliaceae in the third series Coronarieae of the monocots. Engler placed the family in the suborder Liliineae of his ninth order Liliiflorae. In Hutchinson’s arrangement, the family appeared under the first order Liliales of the second division Corolliferae of the monocots.
The Liliaceae is akin to the Amaryllidaceae, the inferior ovary of the latter usually standing as a barrier between the two families. But in Bomarea, Hemerocallis and Ophiopogon of the Liliaceae both superior- and inferior-ovaried flowers are found. Hutchinson’s radically changed the concept of the differentiation of the two families based on the position of the ovary.
He recognised the importance of umbellate inflorescence as the unifying principle in his classification. For this reason, he included the tribes Agapantheae, Allieae and Gillesieae in the Amaryllidaceae, which were formerly placed in the Liliaceae. Moreover, Agave and Yucca are quite similar cytologically in having 5 pairs of large and 25 pairs of small chromosomes.
Yet, the former was placed in the Liliaceae and the latter in the Amaryllidaceae by earlier taxonomists Mckelvey and Sax, 1933; Whitaker, 1934; Granick, 1944. On the basis of his studies of the floral anatomy of the Liliales, Anderson (1940) approved of Hutchinson’s transfer of the Allieae and Agapantheae to the Amaryllidaceae. Maia (1941) and Cheadle (1942) also came to the same conclusion through their pollen and anatomical studies respectively.
The Liliaceae originated from the Helobiales or its ancestor, since the flowers of some genera of the Liliaceae, such as Petrosavia possess semi-free carpels. Moreover, the floral structure of Helonias, a member of the Liliaceae, resembles that of the Juncaginaceae, a component of the Helobiales.
The Liliaceae has been considered by botanists to represent the basic monocot stock—a stock which has given rise to many families, formerly thought to be more primitive, by way of reduction. It is usually regarded as the most typical family of the monocotyledonous group.
Number and Distribution of the Liliaceae:
The Liliaceae embraces about 250 genera and 3,000 species. The plants belonging to this family are widely distributed over the earth, but abundant in the warm temperate and tropical zones.
Commonly Occurring Plants of the Liliaceae:
Indian Aloe (Aloe indica L., A. perfoliata Willd.) is a herb with sword-shaped fleshy leaves.
Asparagus racemosus Willd. is a thorny climber, having fasciculated roots and cladodes.
Asphodel (Asphodelus tenuifolius Cav.) and Day Lily (Hemerocallis fulva L.) are garden plants.
Meadow Saffron (Colchicum luteum Baker) is found in the hills.
Dragon Tree (Dracaena spicata Roxb.) and Adam’s-needle or Dagger Plant (Yucca gloriosa L.) are arborescent garden shrubs, characterised by the presence of concentric bundles and secondary thickening of wood.
Glory Lily (Gloriosa superba L.), seen in dry places, is a climber with the tips of leaves turned into tendrils.
Bow-string Hemp (Sansevieria roxburghiana Schult. f.) is a perennial herb with a rosette of fleshy concave sharp-pointed leaves.
Sarsaparilla (Smilax zeylanica L.) is a prickly climber with stipular tendrils and reticulate leaf venation.
Economic Aspects of the Liliaceae:
“Economically, the Liliaceae ranks very high in the number of important ornamentals”. The species of Agapanthus, Brodiaea, Convallaria, Dracaena, Hemerocallis, Kniphofia, Muscari, Yucca, etc. are cultivated as ornamentals. The growing of the species of Hyacinthus, Lilium, Scilla, Tulipa and other genera is an important industry in Holland.
Several plants of the Liliaceae yield food-stuff. Shallot is derived from Allium ascalonicum, Onion from A. cepa, Leek from A. porrum, Garlic from A. sativum and Chives from A. schoenosprasum. Asparagus officinalis is raised for the edible young shoots, Chlorophytum arundinaceum for the edible roots, Lapageria rosea (Chile) for the edible fruits and Ophiopogon japonicus for the edible tubers.
Some plants of the Liliaceae are of medicinal value. ‘Aloin’, important in the drug trade, is secured from Aloe africana, A. barbadensis, etc. Colchicum autumnale yields ‘colchicine’, an alkaloid used as a drug. ‘Sarsaparilla’, another medicine, is obtained from the roots of Smilax medica (Mexico), S. officinalis (Hondurus) and S. ornata (Jamaica). Another medicinal plant is Veratrum album whose rhizomes yield ‘veratrin’.
A few plants of the Liliaceae furnish fibres. ‘New Zealand flax’ is derived from Phormium tenax and ‘bow-string hemp’ from Sensevieria roxburghiana. Yucca filamentosa also yields a kind of tenacious fibres from the leaves.
The plants of the Liliaceae are put to a variety of uses. Hyacinthus orientalis (France) is cultivated for ‘hyacinth’, a perfume. The bulbs of Scilla give us a glucoside which is in demand as a rat poison. The bulbs of Urginea form ‘red squill’, used in rodent control. The leaves of Xanthorrhoea hastilis (Australia) yield an acaroid resin which is used for making sealing wax, gold size, etc.
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