. Agricultural botany, theoretical and practical. Botany, Economic; Botany. CHAPTER XXVII. CRUOIFERJE. I. General characters of the Order.—Flowers (Fig. ii6, A), regular, hypogynous. Calyx polysepalous, four sepals in two whorls, deciduous; corolla polypetalous, four petals in one whorl: androecium of six stamens in two whorls, /eira- dynamous, that is, four sta- mens with long filaments, and two with short ones. (Fig. II6, B). Gynsecium (Fig. ii6, C) syncarpous, two car- pels : the ovules are arranged on two parietal placentas; the ovary is sometimes unilocular, but more frequently divided in
. Agricultural botany, theoretical and practical. Botany, Economic; Botany. CHAPTER XXVII. CRUOIFERJE. I. General characters of the Order.—Flowers (Fig. ii6, A), regular, hypogynous. Calyx polysepalous, four sepals in two whorls, deciduous; corolla polypetalous, four petals in one whorl: androecium of six stamens in two whorls, /eira- dynamous, that is, four sta- mens with long filaments, and two with short ones. (Fig. II6, B). Gynsecium (Fig. ii6, C) syncarpous, two car- pels : the ovules are arranged on two parietal placentas; the ovary is sometimes unilocular, but more frequently divided into two compartments by a ' false' partition, which is an outgrowth from the placentas. Fruit, usually a dehiscent silique or silicula (see Raphanus, p. 385), seeds without endosperm or with only traces of it. When placed in water the cuticle of the testa of the seeds from the dehiscent fruits generally swells up into a slimy sticky substance, which fixes the seed to the ground, tends to store up water dur- ing germination, and also aids in the distribution of the seeds. Situated on the receptacle, generally atthe base of each of the two short stamens, are greenish nectaries. Pollination is chiefly brought about by insects. The anthers are so placed in regard to the stigmas and nectaries, that insects 365 Fig. 116.—A^ Flower of turnip. ^, The same, after stripping off the calyx and corolla, showing the androecium and gynEecium. s Two short stamens; / four long stamens;_ st stigma of gynaecium; « nectary. C, Gynsecium. o Its ovary ; b style; st 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 Percival, John, 1863-1949. New York, H. Holt
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