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 (Fmx- 

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

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

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



FIG. 328. Primulales and Gentianales : A, flower of loosestrife (Steiro- 

 nema). 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 {Gentiana}, 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 

 (Limnanthemum) 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 



