. Lessons with plants. Suggestions for seeing and interpreting some of the common forms of vegetation. Fig. flowers of willow. WSAT IS A FLOWEBf CONCLUDED 137 150. It so happens that in the greater numberof plants the pistils and stamens in any flowermature at different times. That is, the pollen mayall be discharged before the stigma is receptive,or the stigma may shrivel and die before theanthers open. In other words, there is frequentlyonly a small chance of a flower fertilizing must be some means, then, of assuring thetransfer of pollen. The commonest means arew
. Lessons with plants. Suggestions for seeing and interpreting some of the common forms of vegetation. Fig. flowers of willow. WSAT IS A FLOWEBf CONCLUDED 137 150. It so happens that in the greater numberof plants the pistils and stamens in any flowermature at different times. That is, the pollen mayall be discharged before the stigma is receptive,or the stigma may shrivel and die before theanthers open. In other words, there is frequentlyonly a small chance of a flower fertilizing must be some means, then, of assuring thetransfer of pollen. The commonest means arewind and insects. The flower does not need toattract the wind, but it must have some meansof letting the insects know where it is. Theshowy petals are perhaps the sign-boards. At allevents, insects maynot visit someflowers when thepetals are re-moved, althoughthey are attractedby them when thepetals are undis-turbed (see 273&). 150a. This non-con-currence in maturity ofthe essential organs isknown as Fig. flowers of willow. 151. If the pollen may be carried from flowerto flower, it is not essential that every flower 138 LESSONS WITH PLANTS have stamens. Figs. 136 and 137 are the softbodies which push out from the pussy willowsin spring. They are really masses of are branches, since they are borne in theaxil of a bract or scale. The cluster in Fig. 136has members of a single kind, a; and these areclearly pistils, since they bear an ovary and haveno pollen (no anthers). The cluster in Fig. 137also has members of a single kind, &, but theyare unlike the members of Fig. 136. They arestamens, as may be determined by the pollen andthe filaments, and the absence of ovary. In bothcases, the parts have no envelopes, but are bornein the axil of a hairy or woolly scale; and itis this silky wool which gives the name of pussywillow to the plant. Such flowers are said to beimperfect, because they have only stamens or pis-tils, in distinction to the perfe
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