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Let us learn about Family-Ruscaceae. After reading this article you will learn about: 1. Explanation on Family-Ruscaceae 2. Economic Importance of Family – Ruscaceae.
Explanation on Family-Ruscaceae:
According to Hutchinson there are only three genera (i.e., Danae, Semele and Ruscus) in this family.
Distribution:
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The genera are quite restricted in their distribution. They are chiefly found in Western Europe and Mediterranean region. In our country the family is represented by the genus Ruscus, which is cultivated in the gardens.
Habit:
The plants are either woody or climbing shrubs.
Stem:
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The stem is woody, either erect or climbing. The stems are also modified into leaf like cladodes (e.g., in Ruscus), which are acute and sharply pointed.
Leaves:
The leaves are reduced to small scale-like structures developing in the axils of the leaf-cladodes.
Inflorescence:
Cymose, the flowers are mostly solitary axillary. Sometimes terminal racemes are developed which remain free from cladodes.
Flowers:
The flowers are small, hermaphrodite or unisexual, when unisexual the plants are dioecious.
Perianth:
It consists of six perianth leaves arranged in two whorls of three each. The perianth leaves are either free or somewhat connate. When connate, there is a fleshy corona.
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Androecium:
In male flowers, the androecium consists of six or three stamens. The filaments form a column. The anthers are extrorse. Sometimes rudimentary ovary is found in the male flower.
Gynoecium:
In female flowers, the gynoecium consists of three carpels, which are syncarpous. The ovary is superior uni or trilocular, two ovules in each loculus when three chambered. The staminodes are present.
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Fruit:
A roundish berry.
Seeds:
The seeds are endospermic with a small cylindrical embryo.
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Pollination:
The pollination takes place through the agency of insects.
Economic Importance of Family – Ruscaceae:
The family is of little economic value, having a few ornamental plants grown in the gardens and homes, e.g., Ruscus.
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Systematic Relationships:
Engler and Prantl have placed the Liliaceae in the order-the Lilliflorae. Bentham and Hooker have placed the Liliaceae in the series—Coronarieae, Hutchinson has placed the Liliaceae together with other five families (i.e., Trilliaceae, Smilacaceae, Tecophilaeaceae, Pontederiaceae and Ruscaceae) in his order—the Liliales.
He included the genera, Lilium, Aloe, Asparagus, Asphodelus, Gloriosa, etc., in the Liliaceae; Smilax in the Smilacaceae and Ruscus in the Ruscaceae.
He included the genus Allium in Amaryllidaceae and Dracaena, Yucca, Agave, Cordyline, etc., in the Agavaceae of his order—Agavales. Hutchinson, however has distinguished his Liliaceae and Amaryllidaceae on the basis of the inflorescence character which is probably supposed to be more stable and fundamental. Hutchinson, however, transferred the umbellate spathaceous genera to Amaryllidaceae.
The genera Agapanthus and Allium have umbellate inflorescences and are closely related anatomically and, therefore, Hutchinson has placed them in the Amaryllidaceae. According to him the flowers in Liliaceae are never arranged in umbellate inflorescences.
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The morphologists, such as Cheadle (1942) the Maia (1941), supported the transfer of Agapantheae, Allieae and Gilliesieae to the Amaryllidaceae on the basis of their pollen studies.
Lawrence stated that from the stand-point of its phylogeny, the Liliaceae is now believed to represent basic monocotyledonous stock from which ancestral liliaceous stocks have evolved the majority of present day petaloid monocot families, such as Amaryllidaceae, Iridaceae, Palmae, Araceae and Orchidaceae.
It is also thought that its ancestral stocks have been possibly derived from those of Commelinales and Butomales. There is a general belief that within the Liliaceae the groups that possess rhizomes are more primitive than the groups which possess bulbs.
