Text-book of botany, morphological and physiological . cture (foliar or floral) which can be divided into two similar halves, or the parts of whichare radially disposed around a central point; see p. 1S3.—Ed.] 470 PHANEROGAMS. of small green leaves, as in the Chenopodiacece and Urticaceae, but is sometimeslarge, of delicate structure and brightly coloured (petaloid), as in Aristolochia,Mirabilis, &c. But in both classes of Angiosperms (Monocotyledons and Dicoty-ledons) the perianth is usually composed of two alternating whorls consisting of thesame number of leaves, two, three, four, five, or
Text-book of botany, morphological and physiological . cture (foliar or floral) which can be divided into two similar halves, or the parts of whichare radially disposed around a central point; see p. 1S3.—Ed.] 470 PHANEROGAMS. of small green leaves, as in the Chenopodiacece and Urticaceae, but is sometimeslarge, of delicate structure and brightly coloured (petaloid), as in Aristolochia,Mirabilis, &c. But in both classes of Angiosperms (Monocotyledons and Dicoty-ledons) the perianth is usually composed of two alternating whorls consisting of thesame number of leaves, two, three, four, five, or rarely more. In most Dicotyledonsand many Monocotyledons the form and structure of these two whorls is verydifferent; the outer whorl or Ca/jx consisting of stouter, green, usually smaller leaves{Sepals), while the inner whorl or Corolla is more delicate, and is formed of white orbright-coloured, usually larger leaves {Petals). It is however more convenient, forthe sake of brevity, as Payer has already suggested, to designate the inner whorl as. Fig. 330.—Hippiiris vulgaris; A piece ot an erect stem, the flowers standing in the axils of tlie whorl of leaves (which havebeen cut off); B horizontal section of a female flower above the ovary, p perianth, cp carpel; C horizontal section of the anther ;I—IV longitudinal section of flowers in various stages of development, a anther, f filasnent, g: style, n stigma, / perianth,fk the inferior ovary, sk the pendulous and anatropous ovule. • corolla, the outer whorl as calyx, even in those cases where the structure of the twois the same^; and this is the more necessary since the contrast of structurereferred to is frequently wanting, both whorls being either sepaloid, as in Jun-cacese, or both petaloid, as in Lilium; in Helleborus, Aconitum, and some otherspecies, the outer whorl or calyx alone is petaloid, the inner whorl or corollabeing transformed into nectaries. In some Dicotyledons the perianth does notconsist of alternating
Size: 1916px × 1304px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1870, booksubjectbotany, bookyear1875
