By J. CH. SAWER, F.L.S.
Lavender - technically Lavandula. This name is generally considered to be derived from the word lavando, gerund of the verb lavare, "to wash" or "to bathe," and to originate from the ancient Roman custom of perfuming baths with the flowers of this plant.
The general aspect of the various species which compose this genus of labiate plants, although presenting very characteristic differences, merges gradually from one species to another; all are, in their native habitat, small ligneous undershrubs of from one to two feet in height, with a thin bark, which detaches itself in scales; the leaves are linear, persistent, and covered with numerous hairs, which give the plant a hoary appearance.
The flowers, which are produced on the young shoots, approximate into terminal simple spikes, which are, in vigorous young plants, branched at the base and usually naked under the spikes.
As a rule, lavender is a native of the countries bordering on the great basin of the Mediterranean - at least eight out of twelve species are there found to be indigenous on mountain slopes.
The most commonly known species are L. vera, L. spica and L staechas. Commercially the L. vera is the most valuable by reason of the superior delicacy of its perfume; it is found on the sterile hills and stony declivities at the foot of the Alps of Provence, the lower Alps of Dauphiné and Cevannes (growing in some places at an altitude of 4,500 feet above the sea level), also northward, in exposed situations, as far as Monton, near Lyons, but not beyond the 46th degree of latitude; in Piedmont as far as Tarantaise, and in Switzerland, in Lower Vallais, near Nyon, in the canton of Vaud, and at Vuilly. It has been gathered between Nice and Cosni, in the neighborhood of Limoné, on the elevated slopes of the mountains of western Liguria, and in Etruria on hills near the sea. The L. spica, which is the only species besides L. vera hardy in this country, was formerly considered only a variety of L. vera; it is distinguished by its lower habit, much whiter color, the leaves more congested at the base of the branches, the spikes denser and shorter, the floral leaves lanceolate or linear, and the presence of linear and subulate bractes.
It yields by distillation an oil termed "oil of spike," or, to distinguish it from oil of L. staechas, "true oil of spike." It is darker in color than the oil of L. vera, and much less grateful in odor, reminding one of turpentine and rancid coker nut oil. It is used by painters on porcelain, and in the manufacture of varnishes. It is often largely admixed with essence of turpentine.
L. Staechas (Stichas) was discovered prior to the year 50 A.D. in the Staechades Islands (now the Islands of Hyères), hence the name. At present it is found wild in the South of Europe and North of Africa, also at Teneriffe. The leaves are oblong linear, about half an inch long (sometimes an inch long when cultivated), with revolute edges and clothed with hoary tomentum on both surfaces; the spike is tetragonal, compact, with a tuft of purple leaves at the top; the calyces are ovate and slightly shorter than the tube of the corolla. The whole plant has a strong aromatic and agreeable flavor. There is a variety of this species (L. macrostàchya) native of Corsica, Sicily, and Naples, which has broader leaves and thicker octagonal spikes.
L. staechas is known in Spain as "Romero Santo" (sacred rosemary). Its essential oil (also that of L. dentata) is there obtained for household use by suspending the fresh flowering stalks, flowers downward, in closed bottles and exposing them for some time in the sun's rays; a mixture of water and essential oil collects at the bottom, which is used as a haemostatic and for cleansing wounds.
The specific gravity of Spanish oil of L. staechas is 0.942 at 15° C. It boils between 180° and 245°. The odor of this oil is not at all suggestive of that of lavender, but resembles more that of oil of rosemary, possessing also the camphoraceous odor of that oil. In India this oil is much prized as an expectorant and antispasmodic.
LAVANDULA VERA. LAVANDULA SPICA.
(From photographs of the plants. Natural size.)
The other species which are distinctly characterized are L. pedunculata, L. viridis, L. dentata, L. heterophylla, L. pyrenaica, L. pinnata, L. coronopifolia, L. abrotonoides, L. Lawii, and L. multifida.
The L. multifida is synonymous with L. Burmanii. In Spain the therapeutic properties of L. dentata are alleged to be even more marked than in the oils of any of the other species of lavender. It is said to promote the healing of sluggish wounds, and when used in the form of inhalation to have given good results in cases of severe catarrh, and even in cases of diphtheria. In odor this oil strongly suggests rosemary and camphor. Its specific gravity is 0.926 at 15° C. It distills almost completely between 170° and 200°.
The specific gravity of the oil of L. vera (according to Flückiger and Hanbury, Pharmacographia) ranges between 0.87 and 0.94. The same authorities state that in a tube of 50 millimeters the plane of polarization is diverted 4.2° to the left.
Dr. Gladstone found (Jnl. Ch. Soc., xviii., 3) that a sample of pure oil of L. vera, obtained from Dr. S. Piesse, indicated a specific gravity of 0.8903 at 15° C., and that its power of rotating the plane of polarization (observed with a tube ten inches long) was -20°. Compared with these results he found the sp. gr. of oil of turpentine to be 0.8727, and the rotatory power -79°.
Although L. staechas was well known to the ancients, no allusion unquestionably referring to L. vera has been found in the writings of classical authors, the earliest mention of this latter plant being in the twelfth century, by the Abbess Hildegard, who lived near Bergen-on-the-Rhine. Under the name of Llafant or Llafantly, it was known to the Welsh physicians as a medicinal plant in the thirteenth century. The best variety of L. vera - and there are several, although unnamed - improved by cultivation in England, presents the appearance of an evergreen undershrub of about two feet in height, with grayish green linear leaves, rolled under at the edges, when young; the branches are erect and give a bushy appearance to the plant; the flowers are borne on a terminal spike, at the summit of along naked stalk, the spike being composed of six to ten verticillasters, more widely separated toward the base of the spike; in young plants two or four sub-spikes will branch alternately in pairs from the main stalk; this indicates great vigor in the plant, and occurs rarely after the second year of the plant's growth. The floral leaves are rhomboidal, acuminate, and membraneous, the upper ones being shorter than the calyces, bracteas obovate; the calyces are bluish, nearly cylindrical, contracted toward the mouth, and ribbed with many veins. The corolla is of a pale bluish violet, of a deeper tint on the inner surface than the outer, tubular, two-lipped, the upper lip with two and the lower with three lobes. Both the corolla and calyx are covered with stellate hairs, among which are embedded shining oil glands, to which the fragrance of the plant is due.