. Notes on the life history of British flowering plants. Botany; Plant ecology. C4RAMINE^ 433 In some of the species the points of the roots are covered with hard scales, which enables them to force their way. The common Couch-grass has thus been known to bore through the roots of trees. Fig. 348.—Transverse section of half of leaf of Poa annua including the median keel. X about 50. Six vascular bundles are represented in the half of the blade, the strongest one is girdered with Kclerenchyma. m, lines of motor cells on upper face above the median vascular bundle. The flowers of Grasses have as
. Notes on the life history of British flowering plants. Botany; Plant ecology. C4RAMINE^ 433 In some of the species the points of the roots are covered with hard scales, which enables them to force their way. The common Couch-grass has thus been known to bore through the roots of trees. Fig. 348.—Transverse section of half of leaf of Poa annua including the median keel. X about 50. Six vascular bundles are represented in the half of the blade, the strongest one is girdered with Kclerenchyma. m, lines of motor cells on upper face above the median vascular bundle. The flowers of Grasses have as a rule definite hours for opening. Poa, Kceleria, and Avena elatior take the lead between 4 and 5 ; Briza media, Aira ccespitosa, and Barley, are a little later, between 5 and 6 ; a good many species, Rye, some Festucas, Andropogon, Dactylis, between 6 and 7; Alopecurus, Phleum, and Antho- xanthum, between 7 and 8. Then comes an interval. At 11 Agrostis opens; between 12 and 1 Melica, Molinia, Nardus, Elymus, Sclero- chloa, and some species of Calam- agrostis. Some species of Bromus open about 2, some of Avena about 3, Agropyrum at 4, and, lastly, Aira Jlexuosa between 5 and 6. Holcus is peculiar. It opens under favourable circum- stances twice, at 6 in the morn- ing, and 7 in the evening. Each flower takes from 15 to 20 minutes. Wheat is said to open at any time of the day. The anthers scatter about two-thirds of their pollen, and drop one-third in their own flower, which, however, gives better results if cross-fertilised. Rye is said to be quite sterile to its own pollen. 2 F. Fig. 349.—Transverse section of leaf of Nardus stricta. X about 50. The shaded portions represent support- ing tissue (sclerenchyma). in, traces of motor cells at base of furrow in upper Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble t
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Keywords: ., bookauthorlub, bookcentury1900, bookdecade1900, booksubjectbotany
