DEVELOPMENT OF PLANTS 



441 



that the two pistils often do not cohere, doubtless a survival of 

 a more primitive condition. The Gentianales include the ash (Frax- 

 inits), lilac (Syringa), Forsythia, olive (Olea), valued for fruit 

 and oil, fringe tree (Chionanthus), privet (Ligustrum), jasmine, 

 Strychnos, yielding the alkaloid strychnine, oleander (Xeriitm) , 



Fig. 328. Primulales and Gentianales: A, flower of loosestrife (Stciro- 

 ncma). Above flower in section, showing cohesion of single row of sta- 

 mens to base of corolla and the numerous ovules on a* free central pla- 

 centa. These are the most important characteristics of the order. B, 

 fringed gentian (Goitiaiia) , showing leaf arrangement and twisting of 

 petals in bud, b, characteristics of the order. C, section of flower. D, 

 fruit, the two carpels separated. 



the gentians, marsh pink (Sabbatia) , the aquatic floating heart 

 (Liiiniaiithciiutiii) and the highly specialized plants of the dog- 

 bane and milkweed families. The latter family is distinguished 

 by the microspores being united into club-shaped pollinia that 



