CLASSIFICATION OF SYMPETALAE 255 



The primitive characters are the indefiniteness in the number 

 of sepals and petals, ranging from 4 to 8, occasional polypetaly, 

 and the often numerous stamens and carpels. Consistency 

 would seem to demand that the Ebenales be regarded as the 

 most primitive of the Sympetalae, even the definite cyclic num- 

 bers not being established. At the same time, there is adherence 

 of a single stamen cycle to a sympetalous corolla, and distinct 

 epigyny. The stamen cycles are peculiarly fluctuating, ranging 

 from three or four cycles, through all stages of suppression of 

 the outer cycles, to a single opposed cycle. This latter feature is 

 suggestive of the Primulales, but the multilocular ovary with 

 usually large solitary ovules is suggestive neither of Primulales 

 nor Ericales. The tropical forms certainly deserve careful mor- 

 phological investigation, and are doubtless related to the Myr- 

 sinaceae, and in our judgment are to be included in any discus- 

 sion of the most primitive Sympetalae. 



In the five following alliances the tetracyclic character seems 

 to be well established, and the prevailing formula is sepals 5, 

 petals 5, stamens 5, carpels 2. In the three previous isocarpic 

 alliances there is every transition from the pentacyclic to the 

 tetracyclic condition, and among the more primitive anisocarpic 

 families the carpels are often three before two becomes the 

 established number. Of the remaining alliances the first three 

 are hypogynous. 



IV. GEXTIAXALES.* This includes the Oleaceae, Salvado- 

 raceae, Loganiaceae, Gentianaceae, Apocynaceae, and Asclepia- 

 daceae, together containing about 4,200 species, the large fami- 

 lies being Asclepiadaceae with about 1,720 species, Apocyna- 

 ceae with 975, and Gentianaceae with 725. 



With this alliance the grouping into developmental lines 

 becomes indefinite and perplexing, for the numerous families 

 intergrade in every direction. There is no distinctive character 

 that separates this alliance from the great alliance Tubiflorales. 

 The fact that the corolla is generally twisted in aestivation 

 seems to be the most useful character, and has suggested a name 

 for the series, and the constantly opposite leaves is a supple- 

 mentary character. 



The lower members of the alliance are the Oleaceae and 



* COXTOBTAE of Engler. 



