THE ORIGIN OF SEX IN PLANTS 9 



rapidly advanced in the last decades. Many Botanists 

 still living have witnessed the gradual steps of observa- 

 tion. These were first made among the simpler, or lower 

 organisms. Observations have since been extended, till 



FIG. 3. 



Euglena gracilis. A, form with green colouring bodies (ch.) ; n = nucleus ; v = 

 vacuole and red eye-spot; g = flagellum; 5 = form with small green colouring 

 bodies; C = colourless saprophytic form, occurring in nutrient solutions in 

 absence of light ; D resting cyst ; r = red eye-spot ; E = germination of resting 

 cyst by division into four daughter cells, which later escape. (After Zumstein. 

 A, C x 630 ; B x 650 ; D, E x 1000. From Strasburger.) 



now a continuous record can be given even of the 

 complicated sexual production of new germs in the 

 Higher Plants. Moreover, by comparison of lower and 

 simpler forms of Plant-Life it is possible now to obtain 

 some idea of the origin and nature of Sex in Plants. A 



