This section is from the book "Sub-Alpine Plants Or Flowers Of The Swiss Woods And Meadows", by H. Stuart Thompson. Also available from Amazon: Sub-Alpine Plants: Or, Flowers of the Swiss Woods and Meadows.
Herbs, with usually hollow stems, except at the nodes, and narrow, parallel-veined, entire, alternate leaves, sheathing at the base; but the sheaths usually split open on the side opposite the blade, and end in a small appendage called a ligule. Flowers in spikelets, arranged in spikes, racemes, or panicles. Each spikelet generally consists of 3 or more chaff-like scales or bracts called glumes, arranged alternately, with their concave face towards the axis. The 2 lowest glumes are usually empty, but the flowering glumes enclose a smaller scale called a palea, which usually has 2 longitudinal veins or ribs. The flower is within the palea or between it and the flowering glume. The true flower usually consists of 2 almost microscopical scales called lodicules and of 3 stamens (rarely 6) and of an ovary with one cell and one ovule, crowned by two more or less feathery styles. However, the flower is generally considered to include the flowering glume and the palea. The fruit is a 1-seeded grain, consisting of the real seed and pericarp; and is either free or enclosed.
The embryo or germ is small, at the base of a mass of mealy albumen.
Several other points will arise in any extended and exact study of this large and somewhat difficult family - the Grasses are distinctly more difficult than the Sedges, and they require careful dissection - but the outline indicated above is sufficient for the purpose of the average botanical student.
Graminece is one of the largest families, its representatives being spread throughout the globe. At least 4000 species are known to Science. Grasses are found from the burning plains of the Equator towards the North and South Pole as far as any Flowering plants have been seen, and from the coast (several actually growing in and matting together the sands of the sea-shore) to the snow-capped summits of some of the highest mountains. In temperate regions they form the chief green carpeting of the soil, while in tropical climates some species of Bamboo attain the height of tall trees. Lastly, but of most importance, in every country inhabited by man grasses are cultivated as cereals for food. Switzerland in bygone ages knew something of the value of these cereals, for several varieties of Barley were found in Swiss lake dwellings in deposits of the Stone Period.
About 70 species of true Grasses are found in the High Alps of Central Europe, of which number many extend above 8000 feet.
More than 100 others grow in the lower mountains and adjacent plains, but it is almost impossible to say what proportion of the whole are to be found in the sub-Alps, and the number of grasses which are purely sub-alpine is extremely small.
The following genera comprise most of the high Alpine species and some of the sub-alpine, viz. Phleum, Agrostis, Deschampsia, Stipa, Trisetum, Avena, Sesleria, Poa, and Festuca.
In addition there are many sub-alpine grasses which belong to the following genera, viz. Alopecurus, Aira, Anthoxanthum, Milium, Sieglingia (Triodia), Koeleria, Melica, Cynosurus, Nardus.
In the whole of Switzerland there are, on the authority of Schinz and Keller, 169 species of Gramineae in addition to a few sub-species.1 In the British Isles there are not more than about 135 species, excluding all varieties, notwithstanding the very long coastline and great variety of geological formation.
We regret that from want of space it is impossible to give descriptions of the grasses, for any adequate account of so numerous a family would make the volume too large.
1 Flore de la Suisse, by Schinz and Keller. Ed. francaise par Wilczek et Schinz (1909).