LF.S30V 17.] 



IJ.) 



I'lidcr tlio mlcroscopo it is found to consist of pjraiiis, nsu;illy round or 

 oviil, and all alike in tiic same specie's, hut very diflerent in dUlcrcnt 

 plants. So that the i)lant may sometimes he recognized from the 

 pollen alone. 



21)8. A grain of polh-n is made up of two coats ; the outer coat 

 thit-kish, hut weak, and frequently adorned with lines or hands, or 

 studded with points ; tlie inner coat is extremely thin and delicate, 

 but extensible, and its cavity is filled with a thiekish fluid, often 

 rendered turbid by an immense number of minute grains that float 

 in it. When wet, the grains absorb the water and swell so much 

 that many kinds soon burst and discharge their contents. 



299. Figures 241-250 represent some common sorts of pollen, 

 magnified one or two hundred diameters, viz. : — A pollen-grain of 

 the ]\Iusk Plant, spirally grooved. One of Sicyos, or One-seeded 

 Cucumber, beset with bristly points and marked by smooth bands. 

 One of the "Wild lialsam-Apple (Echinocystis), grooved lengthwise- 

 One of Hibiscus or Kose-Maliow, studded with prickly points. One 

 of Succory, many-sided, and dotted with fine points. A grain of the 

 curious compound pollen of Pine. One from the Lily, smooth and 

 oval. One from Enchanter's Nightshade, with three small lobes on 

 the angles. Pollen of Kalmia, composed of four grains united, as in 

 all the Heath family. A grain from an Evening Primrose, with a 

 central body and three large lobes. The figures number from left 

 to right, beginning at the top. 



