You are here
قراءة كتاب Grasses: A Handbook for use in the Field and Laboratory
تنويه: تعرض هنا نبذة من اول ١٠ صفحات فقط من الكتاب الالكتروني، لقراءة الكتاب كاملا اضغط على الزر “اشتر الآن"

Grasses: A Handbook for use in the Field and Laboratory
pginternal" tag="{http://www.w3.org/1999/xhtml}a">3.

Fig. 1. A plant of Oat (Avena), an example of a typical grass, showing tufted habit and loose paniculate inflorescence (reduced). Figuier.
All our native grasses are herbaceous, and none of them attain very large dimensions. In the following lists I term those small which average about 6-18 inches in the height of the tufts, whereas those over 3 feet high may be termed large, the tufts being regarded as in flower. The sizes cannot be given very accurately, and starved specimens are frequently found dwarfed, but in most cases these averages are not far wrong for the species freely growing as ordinarily met with, and in some cases are useful. I have omitted the rare species throughout, and in the annexed lists have added the popular names.
Large Grasses.
(Over 3 feet.)
Milium effusum (Millet-grass).
Digraphis arundinacea (Reed-grass).
Aira cæspitosa (Tufted Hair-grass).
Arrhenatherum avenaceum (False Oat).
Elymus arenarius (Lyme-grass).
Bromus asper (Hairy Brome).
B. giganteus (Tall Brome).
Festuca elatior (Meadow Fescue).
F. sylvatica (Reed Fescue).
Glyceria aquatica (Reed Sweet-grass).
G. fluitans (Floating Sweet-grass).
Arundo Phragmites (Common Reed).Medium Grasses.
(1-3 feet.)
Phleum pratense (Timothy).
Avena pratensis (Perennial Oat-grass).
Anthoxanthum odoratum (Sweet Vernal).
Alopecurus agrestis (Slender Foxtail).
A. pratensis (Meadow Foxtail).
Agrostis alba (Fiorin).
Psamma arenaria (Sea Mat-grass).
Avena flavescens (Yellow Oat-grass).
Holcus lanatus (Yorkshire Fog).
Hordeum sylvaticum (Wood Barley).
H. pratense (Meadow Barley).
Agropyrum repens (Couch-grass).
A. caninum (Fibrous Twitch).
Lolium italicum (Italian Rye-grass).
Brachypodium sylvaticum (Wood False-Brome).
B. pinnatum (Heath False-Brome).
Bromus erectus (Upright Brome).
B. sterilis (Barren Brome).
B. arvensis (Field Brome).
Festuca ovina (var. rubra, &c.). (Sheep’s Fescue).
F. elatior (var. pratensis). Meadow Fescue.
Dactylis glomerata (Cock’s-foot).
Cynosurus cristatus (Crested Dog’s-tail).
Poa pratensis (Meadow-grass).
P. trivialis (Rough stalked Meadow-grass).
P. nemoralis (Wood Poa).
Molinia cærulea (Flying Bent).
Melica nutans (Mountain Melick).
M. uniflora (Wood Melick).Small Grasses.
(6-18 inches.)
The roots of our grasses are almost always thin and fibrous and are adventitious from the nodes, frequently forming radiating crowns round the base and easily pulled up, and usually broken in the process; but in the case of a few moor grasses—especially Nardus (Fig. 2) and Molinia—the roots are so tough and thick (stringy) as to resist breakage very efficiently. In stoloniferous grasses a similar difficulty of removal may be caused in a slighter degree by the underground stems. In a few cases, e.g. Alopecurus bulbosus (Fig. 3), Poa bulbosa, Phleum pratense and P. Bœhmeri, Arrhenatherum avenaceum, and to a slighter extent in Poa alpina and one or two others, the lowermost internodes and sheaths of the stems may be swollen and stored with food-materials, and a sort of tuber or bulb results; this is especially apt to occur in dry sandy soils. In old lawns, pastures, &c., the roots of Poa annua and others may have nodules on them due to the presence of certain small Nematode worms, Heterodera.
Fig. 2. Nardus stricta. Plant showing tufted habit, and simple spikate inflorescence, with pointed spikelets all turned towards one side (secund) on the rachis (reduced). Note also the bristle-like (setaceous) leaves at length reflexed. Parnell. |
Fig. 3. Alopecurus geniculatus, var. bulbosus. Plant (reduced) showing habit, bulbous shoots and cylindrical spike-like inflorescences (Foxtail type). Notice the inflated sheaths, and the “kneed" lower parts of the ascending stems. Parnell. |
Grasses are annual, biennial, or perennial, and it is often of importance to know which. The point may usually be determined by examining the shoots. If all the shoots have flowering stems in them, and are evidently of the current year, the grass is an annual; but if any shoots have leaves only, it is either biennial or perennial: to determine which is not always easy, but in perennial grasses there will generally be evident remains of older leaf-bases and shoots, and if there are distinct underground stolons or creeping rhizomes as well the point may be considered decided, and the grass is perennial, as is the case with most of our important species. If all the shoots are barren, the grass is a biennial in its first year of growth: if all have flowering stems in them, but show traces of old leaf-bases of the previous year, then the grass is a biennial in its second year. The