. Lessons with plants. Suggestions for seeing and interpreting some of the common forms of vegetation. orphic (two forms). Other flowershave, in addition, an intermediate length of organs, and are said tobe trimorphie. Dimorphic and trimorpMc flowers are also said tobe short-styled, long-styled and mid-styled. Such flowers, as aclass, are said to be heterostyled ; but Gray has proposed thatthey be called heterogonons, since the polymorphism applies to thestamens as well as the pistils. The pupil may examine suchplants as mayflower (epigsea), pickerel-weed or pontederia, oxalis,partridge berry
. Lessons with plants. Suggestions for seeing and interpreting some of the common forms of vegetation. orphic (two forms). Other flowershave, in addition, an intermediate length of organs, and are said tobe trimorphie. Dimorphic and trimorpMc flowers are also said tobe short-styled, long-styled and mid-styled. Such flowers, as aclass, are said to be heterostyled ; but Gray has proposed thatthey be called heterogonons, since the polymorphism applies to thestamens as well as the pistils. The pupil may examine suchplants as mayflower (epigsea), pickerel-weed or pontederia, oxalis,partridge berry or mitehella, large-flowered flax or linum of thegardens, buckwheat, and some of the loose-strifes or lythrums. Thewhole subject is presented in Darwins book, Different Forms ofFlowers on Plants of the Same Species. 278. We have already made out the structureof the sweet pea (Obs. xxxviii., Figs. 201, 202).We shall now watch how the bees visit the flower(Fig. 230). The insect is after the nectar at thebase of the flower, and in order to secure it, thebee alights upon the keel and forces its way in. FiQ. 230. Poliination of the sweet pea. In some instances, the bee stands on the wings of the flower. Q 242 LESSONS WITS PLANTS between the wings. In crowding itself in, the beepushes down upon the keel, and its body is struckby the shaft of pistil and stamens (Fig. 202).Pollen is left upon its abdomen, and the nextflower visited may receive some of it. 278a. This is only one example of the almost innumerable waysin which flowers are pollinated by insects. Some of the specialcontrivances for effecting pollination are remarkably beautiful andexact. We have found that the orchids are highly of this specialization is a direct adaptation to cross-polli-nation by insects; and the pupil who desires to pursue the subjectof cross-pollination should begin with Darwins epoch-making work,The Various Contrivances by which Orchids are Fertilized by In-sects. He should also have M
Size: 1313px × 1904px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorbai, bookcentury1900, bookdecade1900, booksubjectbotany
