All the species of iris we have named were in cultivation in England in the time of Gerarde,—that is, the latter end of the 16th century. The starch of the rhizome was formerly reckoned medicinal, and directions for its preparation are to be found in the Traicté de la Chymie of Le Febvre, i. (1660) 310.
Production—The above-mentioned species of iris are known to the Tuscan peasantry by the one name of Giaggiolo. The rhizomes are collected indiscriminately, the chief quantity being doubtless furnished by the two more plentiful species, I. germanica and I. pallida. They are dug up in August, are then peeled, trimmed, and laid out in the sunshine to dry, the larger bits cut off being reserved for replanting. At the establishment of Count Strozzi, founded in 1806 at Pontasieve near Florence, which lies in the midst of the orris district, the rhizomes, collected from the peasants by itinerant dealers, are separated into different qualities, as selected (scelti) and sorts (in sorte), and are ultimately offered in trade either entire, or in small bits (frantumi), parings (raspature), powder (polvere di giaggiolo o d’ ireos), or manufactured into orris peas.
The growing of orris is only a small branch of industry, the crops being a sort of side-product, but it is nevertheless shared between the tenant and landowner as is usual on the Tuscan System of husbandry.[2461]
In the mountainous neighbourhood of Verona, the rhizomes of Giglio celeste or Giglio selvatico, i.e., Iris germanica, are collected and chiefly brought to the small places of Tregnano and Illasi, north-east of Verona. The peasants distinguish the selected long roots (radice dritta), the knotty roots (radice groppo) which are used for the issue-peas, and the fragments (scarto) employed in perfumery.
Some orris root is also exported from Botzen in southern Tyrol.
Description.—The rootstock is fleshy, jointed and branching, creeping horizontally near the surface of the ground. It is formed in old plants of the annual joints of five or six successive years, the oldest of which are evidently in a state of decay. These joints are mostly dichotomous, subcylindrical, a little compressed vertically, gradually becoming obconical, and obtaining a maximum size when about three years old. They are 3 to 4 inches long and sometimes more than 2 inches thick. Those only of the current year emit leaves from their extremities. The rhizome is externally yellowish-brown, internally white and juicy, with an earthy smell and acrid taste. By drying, it gradually acquires its pleasant violet odour, but it is said not to attain its maximum of fragrance until it has been kept for two years.
We have carefully compared with each other the fresh rhizomes of the three species under notice, but are not able to point out any definite character for distinguishing them apart.
Dried orris root as found in the shops occurs in pieces of 2 to 4 inches long, and often as much as 1¼ inches wide. A full-sized piece is seen to consist of an elongated, irregularly subconical portion emitting at its broader end one or two (rarely three) branches which, having been cut short in the process of trimming, have the form of short, broad cones, attached by their apices to the parent rootstock. The rootstock is flattened, somewhat arched, often contorted, shrunken and furrowed. The lower side is marked with small circular scars, indicating the point of insertion of rootlets. The brown outer bark has been usually entirely removed by peeling and paring; and the dried rhizome is of a dull, opaque white, ponderous, firm and compact. It has an agreeable and delicate odour of violets, and a bitterish, rather aromatic taste, with subsequent acridity.
A sort of orris root which has been dried without the removal of the outer peel, is found under the name of Irisa in the Indian bazaars, and now and then in the London market. It is, we suppose, the produce of Iris germanica L. (I. nepalensis Wall.), which, according to Hooker, is cultivated in Kashmir. Orris root of rather low quality is now often imported from Morocco; it is obtained, we believe, exclusively from I. germanica.
Microscopic Structure—On transverse section, the white bark about 2 mm. broad, is seen to be separated by a fine brown line from the faintly yellowish woody tissue. The latter is traversed by numerous vascular bundles, in diffuse and irregular rings, and exhibits here and there small shining crystals of oxalate of calcium. It is made up uniformly of large thick-walled spherical porous cells, loaded with starch granules, which are oval, rather large and very numerous; prisms of calcium oxalate are also visible. The latter were noticed already by one of the earliest microscopic observers, Anton van Leeuwenhoek, about the year 1716. The spiral vessels are small and run in very various directions. The foregoing description is applicable to any one of the three species we have named.