. The classification of flowering plants. Plants. UMBELLIFERAE 413 such are the biennials, as Daucus Carota (Carrot), while Ferula has a vegetation-period of several years. Polycarpic species persist by means of subterranean tubers or rhizomes or a thickened stem-base; as in species of Heracleum, Peuce- danum and Angelica. The south temperate genus Azorella (fig. 203) has a caespitose habit, forming dense cushions which may be several feet in diameter and persist for many years. Shrubby species are rare, but occur in Bupleurum (in the Spanish B. spinosum the branches are short and spine- like)
. The classification of flowering plants. Plants. UMBELLIFERAE 413 such are the biennials, as Daucus Carota (Carrot), while Ferula has a vegetation-period of several years. Polycarpic species persist by means of subterranean tubers or rhizomes or a thickened stem-base; as in species of Heracleum, Peuce- danum and Angelica. The south temperate genus Azorella (fig. 203) has a caespitose habit, forming dense cushions which may be several feet in diameter and persist for many years. Shrubby species are rare, but occur in Bupleurum (in the Spanish B. spinosum the branches are short and spine- like), and several members of the Austrahan genus Trachymene. Both the main axis and the lateral branches end in an inflorescence; the former is generally the more strongly. Fig. 203. Azorella glabra. A. Portion of plant, slightly reduced. B. Involucre surrounding a single flower. C. Same in fruit. B and C enlarged. (After Weddell.) developed, giving the characteristic habit of many of our common UmbelHfers. In Hydrocotyle, and other genera with a creeping stem, inflorescences are borne only on lateral shoots. An anatomical feature is the presence in all the organs of ethereal oil-, balsam- or resin-canals. Differences in the arrangement and structure of the vascular bundles and the bands of collenchyma afford characters which are more or less constant in individual tribes or smaller groups. The umbellate inflorescence is a very constant character- istic. The arrangement and relative growth of the main axis and its branches afford characters which are often of generic or specific importance. The compound umbel is the com- monest form, but simple umbels also occur (most species of. 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 the original Rendle, A. B. (Alfred Barton), 1865-1938. Cambridge, University press
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectplants, bookyear1904
