. A textbook of botany for colleges and universities ... Botany. SPERMATOPHYTES 255 is poorly expressed in the terms synsepalous, sympetalous, monadelphous, and syncarpous. The syncarpous condition (syncarpy) is extremely common (fig. 568); but the sympetalous condition (sympetaly) is note- worthy as giving name to one of the three divisions of angiosperms. All such terms as " united," " fused," " coalescent," and their technical equiva- lents suggest a very wrong impression as to the origin of the structure concerned. The separate parts implied in the words "
. A textbook of botany for colleges and universities ... Botany. SPERMATOPHYTES 255 is poorly expressed in the terms synsepalous, sympetalous, monadelphous, and syncarpous. The syncarpous condition (syncarpy) is extremely common (fig. 568); but the sympetalous condition (sympetaly) is note- worthy as giving name to one of the three divisions of angiosperms. All such terms as " united," " fused," " coalescent," and their technical equiva- lents suggest a very wrong impression as to the origin of the structure concerned. The separate parts implied in the words " united," etc., never had a separate existence. For example, in many cases separate petals occur; and where there is zonal development they are not separate, but this does not mean that they have " united " or " ; Hypog3my to epigyny. — Zonal development often involves more than a single set. In sympetaly the stamen zone is also usually involved, so. Figs. 569-571. ^ Diagrams to show structure of hypogynous (369), perigynous (570), and epigynous (571) flowers. — After Ganong. that the stamens seem to arise from the tube of the corolla (fig. 564). There are three conditions in reference to zonal development that in- cludes more than one set which are important to note, for they have to do with a distinct evolutionary tendency of the flowers. The most primitive condition is one in which the sets are entirely free from one another (unless it be the corolla and stamens), in which case the flower is hypogynous, mtwrng that the three outer sets arise from beneath the carpel set (fig. 569). In another condition, zonal development involves the three outer sets, resulting in an urnlike structure surrounding the carpels, from the rim of which the distinct sepals, petals, and stamens arise. In this case the flower is perigynous, meaning that the three outer sets seem to arise around the carpel set (fig. 570). In the last condition the zonal developm
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