. Field and woodland plants. earance, that it is alwaysmore or less puzzhngto the beginner,especially as it is fre-quently necessary tonote minute detailsof structure in orderto determine aspecies. The leading char-acteristic of the orderis that denoted byits name ; for theflowers, which aregenerally very smalland white, arearranged in a few instancesthese umbels aresimple ; but in mostthey are comjjound—that is, the stalkswhich radiate fromthe same point onthe main peduncle,and thus form theprimary iimbel, giverise to the lesser stalks of the secondarij umbels, which are similarly a
. Field and woodland plants. earance, that it is alwaysmore or less puzzhngto the beginner,especially as it is fre-quently necessary tonote minute detailsof structure in orderto determine aspecies. The leading char-acteristic of the orderis that denoted byits name ; for theflowers, which aregenerally very smalland white, arearranged in a few instancesthese umbels aresimple ; but in mostthey are comjjound—that is, the stalkswhich radiate fromthe same point onthe main peduncle,and thus form theprimary iimbel, giverise to the lesser stalks of the secondarij umbels, which are similarly arranged andIjear tlie flowers. There are often bracts at the base of theprimary umbel, in which case they are termed the primary bracts ;and there are frequently secondary bracts or involiicels at the basesof the secondary umbels. The flowers have a, superior calyx, with five teeth ; but thisis often so inconspicuous that it appears like a mere rim round thetop of the ovary. There are also five petals, which generally have. The Orpixe or LmiLONG. m FIELD AND WOODLAND PLANTS their points turned inwards ; and five stamens. The inferior ovaryconsists of two united carpels, surmounted by a fleshy disc thatsupports tlie petals and the stamens, and bears two styles. Special attention must be given to the structure of the fruitsof umbcllifers, for a close examination of these is often necessary for purposes of iden-tification. Tlie twocarjiels are close to-gether, with theii-adjacent surfacesflattened, and arefixed to a centralaxis called the carpo-phore. As the fruitnj), the carpo-2)liore often divides,from above down-wards, becomingY-shaped ; and thecarpels, thus separ-ated, are for a timesuspended on its twoarms. Each carpelis marked byverticalridges, generallynine in number, fiveof them (primaryridges) being moreprominent tlian thefour intermediate or?s e c 0 nd ary ridge on eachside of tlie carpel,nearest to the fissure tliat divides the fruit into two parts, iso
Size: 1327px × 1883px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, bookidfield, bookpublisherlondon
