Leguminosae, the two most numerous orders of phanerogams, but in number of individual plants it probably far exceeds either; whilst from the wide extension of many of its species, the proportion of Gramineae to other orders in the various floras of the world is much higher than its number of species would lead one to expect. In tropical regions, where Leguminosae is the leading order, grasses closely follow as the second, whilst in the warm and temperate regions of the northern hemisphere, in which Compositae takes the lead, Gramineae again occupies the second position.
While the greatest number of species is found in the tropical zone, the number of individuals is greater in the temperate zones, where they form extended areas of turf. Turf- or meadow-formation depends upon uniform rainfall. Grasses also characterize steppes and savannas, where they form scattered tufts. The bamboos are a feature of tropical forest vegetation, especially in the monsoon region. As the colder latitudes are entered the grasses become relatively more numerous, and are the leading family in Arctic and Antarctic regions. The only countries where the order plays a distinctly subordinate part are some extra-tropical regions of the southern hemisphere, Australia, the Cape, Chili, &c. The proportion of graminaceous species to the whole phanerogamic flora in different countries is found to vary from nearly 14th in the Arctic regions to about 125th at the Cape; in the British Isles it is about 112th.
The principal climatic cause influencing the number of graminaceous species appears to be amount of moisture. A remarkable feature of the distribution of grasses is its uniformity; there are no great centres for the order, as in Compositae, where a marked preponderance of endemic species exists; and the genera, except some of the smallest or monotypic ones, have usually a wide distribution.
The distribution of the tropical tribe Bambuseae is interesting. The species are about equally divided between the Indo-Malayan region and tropical America, only one species being common to both. The tribe is very poorly represented in tropical Africa; one species Oxytenanthera abyssinica has a wide range, and three monotypic genera are endemic in western tropical Africa. None is recorded for Australia, though species may perhaps occur on the northern coast. One species of Arundinaria reaches northwards as far as Virginia, and the elevation attained in the Andes by some species of Chusquea is very remarkable,—one, C. aristata, being abundant from 15,000 ft. up to nearly the level of perpetual snow.
Many grasses are almost cosmopolitan, such as the common reed, Phragmites communis; and many range throughout the warm regions of the globe, e.g. Cynodon Dactylon, Eleusine indica, Imperata arundinacea, Sporobolus indicus, &c., and such weeds of cultivation as species of Setaria, Echinochloa. Several species of the north temperate zone, such as Poa nemoralis, P. pratensis, Festuca ovina, F. rubra and others, are absent in the tropics but reappear in the antarctic regions; others (e.g. Phleum alpinum) appear in isolated positions on high mountains in the intervening tropics. No tribe is confined to one hemisphere and no large genus to any one floral region; facts which indicate that the separation of the tribes goes back to very ancient times. The revision of the Australian species by Bentham well exhibits the wide range of the genera of the order in a flora generally so peculiar and restricted as that of Australia. Thus of the 90 indigenous genera (many monotypic or very small) only 14 are endemic, 1 extends to South Africa, 3 are common to Australia and New Zealand, 18 extend also into Asia, whilst no fewer than 54 are found in both the Old and New Worlds; 26 being chiefly tropical and 28 chiefly extra-tropical.
Of specially remarkable species Lygeum is found on the sea-sand of the eastern half of the Mediterranean basin, and the minute Coleanthus occurs in three or four isolated spots in Europe (Norway, Bohemia, Austria, Normandy), in North-east Asia (Amur) and on the Pacific coast of North America (Oregon, Washington). Many remarkable endemic genera occur in tropical America, including Anomochloa of Brazil, and most of the large aquatic species with separated sexes are found in this region. The only genus of flowering plants peculiar to the arctic regions is the beautiful and rare grass Pleuropogon Sabinii, of Melville Island.
Fossil Grasses.—While numerous remains of grass-like leaves are a proof that grasses were widespread and abundantly developed in past geological ages, especially in the Tertiary period, the fossil remains are in most cases too fragmentary and badly preserved for the determination of genera, and conclusions based thereon in explanation of existing geographical distribution are most unsatisfactory. There is, however, justification for referring some specimens to Arundo, Phragmites, and to the Bambuseae.
Bibliography.—E. Hackel, The True Grasses (translated from Engler and Prantl, Die natürlichen Pflanzenfamilien, by F. Lamson Scribner and E. A. Southworth); and Andropogoneae in de Candolle’s Monographiae phanerogamarum (Paris, 1889); K. S. Kunth, Revision des graminées (Paris, 1829–1835) and Agrostographia (Stuttgart, 1833); J. C. Döll in Martius and Eichler, Flora Brasiliensis, ii. Pts. II. and III. (Munich, 1871–1883); A. W. Eichler, Blüthendiagramme i. 119 (Leipzig, 1875); Bentham and Hooker, Genera plantarum, iii. 1074 (London, 1883); H. Baillon, Histoire des plantes, xii. 136 (Paris, 1893); J. S. Gamble, “Bambuseae of British India” in Annals Royal Botanic Gardens, Calcutta, vii. (1896); John Percival, Agricultural Botany (chapters on “Grasses,” 2nd ed., London, 1902). See also accounts of the family in the various great floras, such as Ascherson and Graebner, Synopsis der mitteleuropäischen Flora; N. L. Britton and A. Brown, Illustrated Flora of the Northern United States and Canada (New York, 1896); Hooker’s Flora of British India; Flora Capensis (edited by W. Thiselton-Dyer); Boissier, Flora orientalis, &c. &c.
GRASSHOPPER (Fr. sauterelle, Ital. grillo, Ger. Grashüpfer,
Heuschrecke, Swed. Gräshoppa), names applied to orthopterous
insects belonging to the families Locustidae and Acridiidae.
They are especially remarkable for their saltatory powers, due
to the great development of the hind legs, which are much longer
than the others and have stout and powerful thighs, and also for
their stridulation, which is not always an attribute of the male
only. The distinctions between the two families may be briefly
stated as follows:—The Locustidae have very long thread-like
antennae, four-jointed tarsi, a long ovipositor, the auditory
organs on the tibiae of the first leg and the stridulatory organ
in the wings; the Acridiidae have short stout antennae, three-jointed
tarsi, a short ovipositor, the auditory organs on the first
abdominal segment, and the stridulatory organ between the
posterior leg and the wing. The term “ grasshopper ” is almost
synonymous with Locust (q.v.). Under both “grasshopper”
and “locust” are included members of both families above
noticed, but the majority belong to the Acridiidae in both cases.
In Britain the term is chiefly applicable to the large green
grasshopper (Locusta or Phasgonura viridissima) common in
most parts of the south of England, and to smaller and much
better-known species of the genera Stenobothrus, Gomphocerus
and Tettix, the latter remarkable for the great extension of the
pronotum, which often reaches beyond the extremity of the body.
All are vegetable feeders, and, as in all orthopterous insects,
have an incomplete metamorphosis, so that their destructive
powers are continuous from the moment of emergence from
the egg till death. The migratory locust (Pachytylus cinerascens)
may be considered only an exaggerated grasshopper, and the
Rocky Mountain locust (Caloptenus spretus) is still more entitled
to the name. In Britain the species are not of sufficient size,
nor of sufficient numerical importance, to do any great damage.
The colours of many of them assimilate greatly to those of their
habitats; the green of the Locusta viridissima is wonderfully
similar to that of the herbage amongst which it lives, and those
species that frequent more arid spots are protected in the same
manner. Yet many species have brilliantly coloured under-wings
(though scarcely so in English forms), and during flight are almost
as conspicuous as butterflies. Those that belong to the Acridiidae
mostly lay their eggs in more or less cylindrical masses, surrounded
by a glutinous secretion, in the ground. Some of the
Locustidae also lay their eggs in the ground, but others deposit
them in fissures in trees and low plants, in which the female is
aided by a long flattened ovipositor, or process at the extremity
of the abdomen, whereas in the Acridiidae there is only an
