Reflexed Meadow-grass--_Poa distans_ Rhizomes, 10, 11, 35, 36, 37 Rhomboidal shoot-section, 16, 42 Rib-grass--_Plantago_ Ribbon-grass--_Digraphis arundinacea_ Ribs--the more opaque veins due to the larger vascular-bundles, 22, 25, 62, 91, _127_ Rice, 1 Ridgeless grasses, 25 Ridges, _18_, 21, 22, +23+, _24_, +25+, 26, 47, 51, 53, 54, _65_, _66_, _67_, 68, _69_, _71_, 73, 77, 78, 79, 80, 91 River-banks, 28, 29 Road-sides, 29 Rolled leaves, 15, _16_, 20, 24, 25, 63 Rolling of leaves, 24, 25, 36 Root-cap, _121_ Roots, 8, 12, 35, _121_, 123, 131, 132, 133 Rough Cock’s-foot--_Dactylis glomerata_ Rough Meadow-grass--_Poa trivialis_ Rough Phleum--_Phleum asperum_ Rough-stalked Meadow-grass--_Poa trivialis_ Round shoots, 15, _16_, 42, 50, 57 Ruderal grasses, 29, 32, 34, 35 Rudimentary flowers, 89, 90, 105 Runners, 12, 13, 14 Rushes, 4, 33 Rushy Wheat-grass--_Agropyrum junceum_ Rye--_Secale_, 120, 132, +133+ Rye Brome--_Bromus secalinus_ Rye-grass--_Lolium perenne_ Salt species, 33 Sand-binders, 13, 35, 36, 48, 102, 107, 108 Sand Cat’s-tail--_Phleum arenarium_ Sand dunes, 35, 36 Sand species, 29, 32, 36 Sandy situations, 8, 29, 33 Savannahs, 1, 38 Scaberulous--slightly rough to the touch, 22, 45, 164 Scabrid--rough to the touch, 22, 47, 54 Scarious--as if scorched by fire, 92, 145 Scents, 27 Sclerenchyma--mechanical tissue, 62, _65_, _66_, _67_, +68+, _69_, 70, _71_, 74, 75, 76, 79, 80 _Sclerochloa_--_Poa_ _Sclerochloa maritima_--_Poa maritima_; _S. procumbens_--_Poa procumbens_; _S. rigida_--_Poa rigida_ Scorpion-grass--_Myosotis_ Scutellum, _121_, 123 Sea Barley--_Hordeum maritimum_ Sea Cat’s-tail--_Phleum arenarium_ Sea-grass--_Zostera_ Sea Hard-grass--_Lepturus incurvatus_ Sea Lyme-grass--_Elymus arenarius_ Sea Mat-grass--_Psamma arenaria_ Sea Mat-weed--_Psamma arenaria_ Sea Meadow-grass--_Poa maritima_ Sea Poa--_Poa maritima_ Sea Reed--_Psamma arenaria_ Sea-side grasses, 27, 29 Secondary roots, _121_, 123, 131, 133 Secund--turned to one side, _9_, 89, 108, 109, 114 Sedges, 3, 4, 33, 35, 121 Seed--strictly the contents of the caryopsis (fruit), but in practice the fruit and its adherent paleæ etc. (chaff) are termed “seed,” 119, 120, 121, 123, +124+, 125, _127_, 128, 129, 130, _131_, +134+, +135+-+174+ Seed-coats, 121, _122_ Seedlings, 132, +133+ Semi-aquatic species, 28, 29 Separation of fruits, _124_ Serrulæ--minute tooth-like asperities, 22, 91, _173_ _Sesleria_--Moor-grass, 22, 25, 63, 64, 68, 90, 91, 93, 101; _S. cærulea_, 17, +42+, 67, +108+, 149, +151+ Sessile--sitting directly on an axis without an intervening stalk, 87, 99, 107 Setaceous--bristle-like, _16_, 19, 20, 21, _24_, 45, 111, 113 _Setaria_--_Panicum_ Sexual organs, 134 Shade action of grasses, 35 Shade-grasses, 20, +28+, 33, 34, 70