POLLEN, OR FLOWER-DUST 103 



family called by gardeners Monarda, which possess 

 the characteristic ridges, in this instance six in 

 number. 



The common vegetable-marrow flower of the 

 kitchen garden produces comparatively large 



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Fig. 66. Pollen-grains witll the surface n.-tioiilatpfl in a regnlar 

 lie.xagtjnal manner 



Spherical pollen-grains, shown in Fig. 68, with 

 eight to twelve conspicuous pores each closed with 

 a valve. The extine is studded with tiny spines, 

 and when the intine makes its egress in the 

 form of a pollen-tube it pushes through one of 

 the pores, throwing its closing valve to either 

 side, or removino- it altooether : and even this 

 valve will often have several spines on its sur- 

 face. 



And here let us not fail to remember that we 



