The value of the linen manufacture of Great Britain is between seven and eight millions yearly.
The seeds of the flax plant (Linseed) are used to crush and produce the linseed oil of commerce so extensively used in the production of paints and varnishes, and the cake is used as food for cattle.
17. Aceraceæ (Acer campestre) Maple Tree. (Acer pseudoplatanus) Sycamore Tree.
Maple Tree.
This order contains the Maple and Sycamore, fine trees, not onlyornamental, but producing wood much in request, moreover the Acersaccharinum or Sugar Maple of North America is used to produce sugar,which is obtained from its sap.
18. Rutaceæ (Ruta graveolens) Rue.
Rue.
Rue is a well-known shrub with small pinnate leaves, and possessing astrong and very disagreeable odour; this depends upon the volatile oilwhich is contained in the glands with which the leaves are dotted. Ithas been, from time immemorial, used as a medicine. Another member ofthis order, the Buchu (Diosmia crenata), is also used medicinally.
19. Oxalidaceæ (Oxalis acetosella) Wood Sorrel.
Wood Sorrel.
The Wood Sorrel is very acid, and from its juice is made the salt ofsorrel (which is bin-oxalate of potash), used to get out ink and ironstains from linen, &c. This is supposed to be the true Shamrock.
This completes the orders of Thalamifloræ, which, with the following sub-class, Calycifloræ, contain all our star-like flowers, or those in which the corolla forms a whorl or open ring of petals. The third sub-class contains those chiefly in which the flowers form cups or bells.
Orders of Calycifloræ.
1. Celastraceæ (Euonymus Europæas) Spindle Tree.
Spindle Tree.
This order consists of shrubs or small trees growing in the temperateregions of most parts of the world, and some of the species, asCelastrus venatus, are said to be poisonous; the seeds of the SouthAfrican species are used to express oil from.
2. Rhamnaceæ (Rhamnus catharticus) Buckthorn. (Rhamnus frangula) Black Alder.
Buckthorn.
Buckthorn berries afford a juice which, when made into syrup withsugar, is a popular purgative medicine; the juice precipitated withlime produces the green pigment known to artists as "sap green."The "French Berries" used as a yellow dye-stuff are procured from aspecies of Rhamnus.
The plants producing pods or legumes are among the most important ofthe orders of this class, giving us very many useful and nutritiousplants, which, for the most part, are climbers, as Peas, Beans, &c.The Tamarind and Cassia trees belong to this order, also those whichproduce gum-arabic, catechu, logwood, and indigo. There are betweensix and seven thousand species of the Leguminosæ.
