This section is from the book "Handbook Of Hardy Trees, Shrubs, And Herbaceous Plants", by W. Botting Hemsley. Also available from Amazon: Handbook of hardy trees, shrubs, and herbaceous plants.
Deciduous shrubs bearing simple entire leaves and large terminal clusters of usually sweet-smelling flowers. Corolla salver-shaped. Fruit a flattened 2-celled capsule, when ripe splitting into two boat-shaped pieces, each containing one or two winged seeds. Only about half a dozen species are known to exist in a wild state, and these are found in South-eastern Europe, Persia, Northern India and China. The name is said to be an altered form of the Persian Syrinx, which is applied to the common one.
1. 8. Vulgaris. Common Lilac. - This, with the Laburnum, forms the chief attraction of our shrubberies in Spring, and we should as soon expect to see a garden without a Lilac as without a Laurel. Its origin is somewhat uncertain, though it is believed to have been brought from Persia. At all events it has been in cultivation about three centuries, and has given birth to many superior varieties either by natural variation or intercrossing with other species. The foliage in the common , form is smooth, cordate-ovate, acuminate, and of a rather pale green; and clusters of flowers larger than in the other species. Amongst the many varieties now included in catalogues we may note: Dr. Lindley, having extremely large clusters of reddish lilac flowers; alba, pure white; and violacea, rubra insignis and rosea grandiflora, whose names indicate the various tinges of their flowers. S. dubia or Chinensis is a closely allied species, if indeed it be specifically distinct. It is commonly called the Siberian Lilac, and differs in its smaller stature, narrower leaves, and more profuse inflorescence of reddish violet hue. The variety called Rothomagensis, or Lilas Varin of the French, belongs here, and the fine variety Charles X. (fig. 165) should probably also be referred to this race. It is remarkable for the immense size of its panicles and the beautiful colour of its flowers.
Fig. 165. Syringa vulgaris, var. Charles X. (1/4 nat. size.)
2. S. Josikaea. - This is a shrub of similar habit, but the ovate-lanceolate leaves are wrinkled and of a darker green, and the bluish purple flowers scentless. A native of T r a n s y 1-vania, blooming later than the varieties of vulgaris.
3. S. Emodi. - A tall shrub with warty excrescences on the stems, large oblong reticulately-veined leaves, and lilac or white flowers in erect dense panicles. A native of the mountains of India, scarcely so ornamental as the common species.
4. S. Persica (fig. 166). Persian Lilac. - This is a very distinct species of much smaller size, rarely exceeding 4 or 5 feet in height. The branches, too, are slender and straight, and the smaller ovate-lanceolate leaves are narrowed at the base. The flowers vary in colour from rosy carmine to white. And there is a variety with laciniated foliage. This blossoms in May.
Fig. 166. Syringa Persica. (1/4 nat. size.)