Standley : Some Echinocerei of New Mexico 81 



other radials, are sometimes reflexed rather closely against the 

 ribs of the plant, and in other cases more spreading. This charac- 

 ter, however, seems to have no constancy. 



In the inferior radials the length was from 9 to 36 mm., with 

 the chief mode of the curve at 15 mm. In E. coccincus the length 

 ranged from 9 to 23 mm., with modes at 13 and 16 mm. ; in E. 

 polyacantJms from 10 to 28 mm., with modes at 15 and 19 mm. ; 



and in R conoidais from 10 to 31 mm., with the main mode at 

 20 mm. 



The distances between the areolae and between the ribs were 

 measured because the apparent spininess of the plant is largely 

 dependent upon these distances. It depends not upon either alone, 

 but upon both taken together. The areolae may be very close to 

 each other but the plant does not appear densely spiny because 

 of the distance between the ribs and vice versa. The length of 

 the spines, of course, is of importance in producing this effect of 

 spininess. No satisfactory results were obtained from these meas- 



urements. 



P 



flow 



W f —r 



than those of either of the other two species, and E. conoidais rather 

 more so than E. coccincus. 



The number of ribs is not important for it seems to vary equally 

 in all three species. On a single plant on different branches the 

 number of ribs sometimes varies from ten to twelve. Ten is the 

 most common number. 



The length of the flowers ran from 39 to 90 mm. The largest 



ers were observed on plants of E. conoidcus ; but the number 

 of plants with large flowers was small, so that this is probably not 

 necessarily characteristic of the species. The size of the flowers 

 de pends somewhat upon the amount of water the plant receives. 

 The plants that had been recently transplanted and had not re- 

 eved so much water as the others, produced flowers that were 

 noticeably small 



The shape of the flowers is not the same on all plants. On 

 s °me the flower is long and trumpet-shaped, gradually widening 

 °«tward ; on others the petals and sepals spread abruptly from 

 ab °ut the middle of the flower. The shape of the petals, too, 

 l!. rieS " In about fort y flowers out of seven hundred the petals 



r etuse at the apex. In the others the apices were broadly 



er. 



were 



