The genera of South African plants : arranged according to the natural system / by William Henry Harvey.

  • William H. Harvey
Date:
1868
Catalogue details

Licence: Public Domain Mark

Credit: The genera of South African plants : arranged according to the natural system / by William Henry Harvey. Source: Wellcome Collection.

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    Thus, a flower is, dtnierons, trhmrous, etc., if symmetrical, according as there are 2, 3, etc., pai-ts in each whorl. 80. Flowers are uiisi/mmetrical, or ainsomo-ous, strictly speaking, when any one of the whorls has a different number of parts from the others; but when the carpels alone are reduced in number, the flower is still frequently called symmetrical, or isomerous, if the calyx, corolla, and staminal whorls have all the same number of pai’ts. 81. Flowers are irregular when the parts of any one of the whorls are unequal in size, dissimilar in shape, or do not spread regularly round the axis at equal distances. In descriptions, it is more especially irrcgidmity of the corolla that is rofeiTcd to ; a slight inequality in other psu^ts does not prevent the flower being classed as regular, if corolla or perianth bo rcgultir. ^ 10. The Terianth, and Calyx or Corolla. 82. The Calyx or outer whorl of tho perianth is risually green, smaller than tho corolla, and of coarser texture; sometimes veiy minute, rudi- mentary, or obsolete altogether; sometimes imperfectly whorled, or not whorled at all, or composed (as in Caciue) of a large number of sepals, of which the outer ones jjass gradually into bracts, and tho umer ones into petals. 83. Tlio Corolla or inner whorl of tho perianth is usually coloiu'ed, larger than tho calyx, and of a more delicate texture, and in popular lan- guage is often called the flower. Its pehils, except in double flowers, are rarely indelinito in nuniboi’, and tho whorl more rarely broken than in tho calyx. Sometimes tho petals are very small, rudimentary, reduced to scales (as in Thymelece), or absent altogether. 81. In very many cases tho so-called simple I'erianth is one in which tho soi)als and petals are nearly similar in fonn and texture, and present api)arently a single whorl. The real nature of such a perianth may bo detected by examining an unopened flower-bud, when one half of tho parts will bo found jdaced outside of tho others (as in Anthericum, Ornitho- yalnm, llumex, etc.), indicating an arrangement in two whorls, or calyx and corolla. Hence difl'orent authors may describe tho same flower difle- rently, either as having a single or a double perianth. 85. In tho following tenns tho prelixes exjjrossivo of tho moclifleations of tho corolla and its ])ctals are equally ai)plicablo to tho calyx and its sei)als, or to the ])orianth and its segments. 8C. Tho Corolla is, monopetalous (sometimes called gamopetalous), when the petals are united or soldered together, either ontmely or at the base only, into a cup, tube, or ring. polypetalous (or dialipetalous), when they ai’O all separate or free fi’om tho very base. 87. \Vlion tho petals are partially united in a monopetalous corolla, the lower consolidated portion of tho corolla is called tho tube, whatever bo its shape, and tho free upper portions of the petals are called^ tho teeth, lobes, or segments, according as they are short or long in propoxfion to the whole length of the corolla. When tho calyx or coi’olla enlarges after floweiing it is called aeereseent; when it falls eaily, deciduous or eadueous. 88. Tho flat expanded poi’tion of a petal, coiTosponding to tho blade of tho leaf, is called its limb or lamina ; and the stalk, corresponding to tho petiole, its elaw. ^Vhon there is no claw, tho petals are sessile. 89. The (estivation of a corolla is the arrangement of the petals, or their free portions, in an unexpanded bud. It is valvate, when tho edges of the petals touch, but do not ovcilai); imbricate, when the edges overlap each other, at least near tho top ; twisted, contorted, or convolute, when each petal