Most grasses are glabrous, but there are a number in which hairs are nearly always a prominent feature. It must be remarked, however, that with grasses, as with other plants, the character of pubescence is apt to vary with the situation. In general it may be stated that a hairy grass tends to become more glabrous in a moist situation, and more pubescent in a dry one, but the rule is by no means absolute. In some cases,—e.g. Avena pubescens, A. flavescens, Agropyrum, the hairs are almost entirely confined to the crests of the ridges (Figs. [10], [15]). The following is a list of hairy grasses.
Hairy Grasses.
Holcus (Fig. [15]).
Molinia cærulea.
Brachypodium sylvaticum.
Agropyrum (variable).
Bromus asper.
B. mollis.Hordeum.
Anthoxanthum.
Avena flavescens (Fig. [10]).
A. pubescens.
Triodia.
Kœleria.To a less extent. Festuca sciuroides (on ribs). Melica.
| Holcus (Fig. [15]). Molinia cærulea. Brachypodium sylvaticum. Agropyrum (variable). Bromus asper. B. mollis. | Hordeum. Anthoxanthum. Avena flavescens (Fig. [10]). A. pubescens. Triodia. Kœleria. |
| To a less extent. | |
| Festuca sciuroides (on ribs). | Melica. |
Grasses as a rule are devoid of strong scents[5] or tastes, but Anthoxanthum has a faint but distinct sweet odour, especially as it dries—it is one of the grasses which give the scent to new-mown hay—and a bitter flavour, and Milium, Hierochloe and Holcus are also more or less bitter. Spartina stricta emits a strong unpleasant odour.
The habitat of grasses is of great importance as an aid to determination. No one would expect to find a sea-shore grass growing in a beech-forest, or an aquatic grass on a dry chalk-down; but they are even more true to their habitats than this, and I append the following lists of habitats of British grasses as of use in determining them, though it is not pretended that the limits are absolute.
In the following list “pasture-grass" (P) means useful for grazing, and "meadow-grass" (M) one that is especially valuable for mowing—i.e. for hay. A “weed" (W) is used in its agricultural sense for a grass not useful and not wanted on cultivated land, though often found there.
Meadow- and Pasture-grasses.
Shade-grasses.
Found in woods, copses, &c., under shade.
Melica uniflora (woods, &c.).
Bromus asper (hedges, thickets, and edges of woods).
B. giganteus (hedges and woods).
Aira cæspitosa (moist shade and damp hedges).
Poa nemoralis (woods, shady places and damp mountain rocks).
Milium effusum (moist woods, &c.).
Agropyrum caninum (woods and shady places).
Hordeum sylvaticum (woods and copse).
Brachypodium sylvaticum (woods, hedges and thickets).
Arrhenatherum avenaceum (meadows, hedges and copse).
Festuca sylvatica (mountain woods).Aquatic and Semi-aquatic Grasses.
Found in wet ditches, ponds, and on marshes, river-banks, &c.
Moor-and Heath-grasses.
Downs and dry hill-pastures.
Nardus stricta (moors, heaths and hilly pastures).
Aira flexuosa (heaths and hill pastures).
Molinia cærulea (wet heathy moors, woods and waste places).
Kœleria cristata (dry pasture).
Triodia decumbens (dry heathy and hilly pastures).
Festuca ovina (hilly pastures—especially dry and open—rarer in moist situations).
Agrostis vulgaris and A. canina.Maritime or Seaside Grasses.
Poa maritima (maritime).
P. distans (sandy pastures and wastes near sea).
Elymus arenarius (coasts).
Psamma arenaria (coasts).
Poa bulbosa (waste places in S.E. of England).
Agropyrum junceum (coasts).
Hordeum maritimum (S. and E. coast).
Phleum arenarium (coasts).Ruderal or Vagabond Grasses.
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Melica uniflora (woods, &c.). Bromus asper (hedges, thickets, and edges of woods). B. giganteus (hedges and woods). Aira cæspitosa (moist shade and damp hedges). Poa nemoralis (woods, shady places and damp mountain rocks). Milium effusum (moist woods, &c.). Agropyrum caninum (woods and shady places). Hordeum sylvaticum (woods and copse). Brachypodium sylvaticum (woods, hedges and thickets). Arrhenatherum avenaceum (meadows, hedges and copse). Festuca sylvatica (mountain woods). |