OUR LOCAL FLORA: ITS ECONOMIC ASPECT. 149 
wild than cultivated. Trifolium pratense, Red Clover, is the clover 
most esteemed for agricultural purposes in regard to quantity and 
nutriment. How red clover depends on the number of cats in 
a district, through the intervention of at first humble bees, and 
then of field mice, Mr. Darwin shows in his Origin of Species. 
Trifolium incarnatum, Crimson Clover, the seeds of which are now 
quoted at 4d. per lb., is strictly an annual, never living through a 
second winter. When found wild in Great Britain it is but an 
escape from cultivation. How different is the White Trefoil, or 
Dutch clover — Trifolium repens — a perennial, and abundantly wild 
here and all over England ! 
As of the trefoils so of the vetches — we have more species in 
the wild state than under cultivation. Apparently the most 
important species of vetch is the common Tare, or vetch, Vicia 
angustifolia, which is both wild and cultivated. 
According to the Agricultural Returns just published for 1884, 
there is a large increase in acreage of land under pasture, and for 
1885 there is certain to be a much larger increase. It may there- 
fore be convenient next, after the great fodder plants, to mention 
the Grasses — Order Gramina, always distinguishable from sedges by 
the presence in grasses of a ligule, the thin sheath-like appendage 
at the base, not of the whole leaf, but of the blade where the leaf 
passes into the sheath. The grass family is the most important in 
the vegetable kingdom, comprising the rice and bamboo of hot 
countries, as well as the wheat, rye, barley, and oats, which are 
now general in our agriculture, and maize or Indian corn, at 
present absent from British agriculture, except in Cheshire. 
Cynodon dactylon, Creeping Dog's-tooth Grass, confined to Corn- 
wall, Devon, and Dorset, is curiously absent from the immediate 
vicinity of Plymouth, and is not in the Plymouth Flora. In India, 
where it abounds, it is considered the best pasture grass. Anthox- 
anthum odoratum, Sweet-scented Vernal Grass, is very common 
with us. The flowers of this grass secrete a volatile fluid, containing 
benzoic acid, the cause of the well-known odour of the new-mown 
grass. This is a very valuable plant to farmers in their permanent 
pastures, especially in the latter part of the season, as it continues 
until that period to throw out luxuriant stems and leaves. Phalaris 
canariensis, Canary Grass, is a casual or alien, rare ; and Mr. Briggs 
says, " Nowhere permanent, and the species would disappear were 
it not for the seeds being scattered with refuse from bird-cages, 
