148 THE CACTACEAE. 



An examination of the plant collected by Wislizenus (No. 223) north of Chihuahua, 

 now in the herbarium of the Missouri Botanical Garden and labeled by Dr. Engelmann as 

 0. engelmannii Salm-Dyck, shows that this species is of Schumann's series Fulvispinosae 

 (our series Phaeacanthae) rather than series Tunae. 



Opuntia engelmannii has been more confused than any other species of Opuntia. 

 Salm-Dyck, who first studied the species, doubtless had but a single specimen before him, 

 and this or a duplicate is now in the herbarium of the Missouri Botanical Garden. This 

 type specimen came from near Chihuahua City, from which place Dr. Rose has collected 

 identical material. Dr. Engelmann, who published Salm-Dyck's name, described the 

 plant as erect and 5 to 6 feet high, giving its range from Chihuahua City to Texas. These 

 remarks of his were doubtless based on notes of Dr. Wislizenus, who collected the type, 

 and must have included more than one species; as Engelmann says it is both cultivated 

 and wild, the cultivated plants doubtless referring to some of the many forms grown about 

 towns and ranches. In 1852 Engelmann extends the distribution of the species westward 

 to the Pacific Ocean, referring especially to a San Diego specimen. In 1856 he refers here 

 his previously described species 0. lindhcimcri, and extends the range eastward to the mouth 

 of the Rio Grande and to lower Mexico. Coulter brought all this material together under 

 O. lindhcimcri and four varieties. 



An examination of herbarium and greenhouse specimens shows that at least half a 

 dozen species have been passing under the name of ( ). engelmannii. While certain varieties 

 and specimens are evidently to be excluded from the species, we are still uncertain as to its 

 specific limits. It is quite common about Chihuahua City and extends to Monterey 

 and Saltillo or is represented there by a near ally, while Mr. E. O. Wooton would refer here 

 plants of southern New Mexico, and we are including large, bushy opuntias from Arizona. 



Dr. Rose was inclined at one time to separate the Tucson plant, which seems to have 

 some just claims for specific recognition, but there is a mass of herbarium material which 

 seems to connect this with the true 0. engelmannii. 



Opuntia engelmannii mcmstiosa (Cat. Darrah Succ. Manchester 54. 1908) is doubt- 

 less one of the abnormal forms so common among the flat-jointed opuntias. 



Opuntia cyclodcs, first found by Bigelow near Anton Chico, New Mexico, is certainly 

 of this relationship. The characters of orbicular joints, of small fruit and of stout, usually 

 solitary spines, originally assigned to it, are not constant, for it often has obovate to oblong 

 joints bearing as many as four slender spines and large fruit. 



In 1913 Dr. Rose explored the upper Pecos, especially about Anton Chico, near the 

 type locality, where he collected specimens similar to the Bigelow plant, but these grade 

 into more spiny forms, some bearing as many as five spines at an areole, usually 

 yellow, especially distally, and more slender than in typical O. engelmannii. From the 

 same type locality, and associated with 0. cyclodes, is 0. cxpansa Griffiths, which has more 

 and whiter spines than the typical form, although they are sometimes yellowish with brown 

 bases. 0. dillci Griffiths is also related to O. cyclodcs, but the spines are fewer; Dr. Grif- 

 fiths states, however, that more spines develop on cultivated plants. 



Illustrations: Pac. R. Rep. 4: pi. 8, f. i ; pi. 22, f. 8, 9, all as Opuntia engelmannii cyclodes; 

 Rep. Mo. Bot. Gard. 20: pi. 4, in part, as Opuntia dillci. Ariz. Agr. Exp. Sta. Bull. 67: pi. 

 7, f. i ; Rep. Mo. Bot. Gard. 20: pi. 10; Safford, Ann. Rep. Smiths. Inst. 1908: pi. 10, f. 3, 

 6, all as Opuntia arizonica. Rep. Mo. Bot. Gard. 21: pi. 26, in part, 27, both as Opuntia 

 u'ootonii. Rep. Mo. Bot. Gard. 22: pi. 3, this last as Opuntia gregoriana. Standley, Ann. 

 Rep. Smiths. Inst. 1911: pi. 2; Bull. Torr. Club 32: pi. 10, f. 10 to 13; Cact. Journ. 2: 147; 

 Cact. Mex. Bound, pi. 75, f. i to 4; Cycl. Amer. Hort. Bailey 3: f. 1547; Gard. Chron. III. 

 30 :f. 123; N. Mex. Agr. Exp. Sta. Bull. 78: pi. [5, 6]. 



Plate xxv, figure 3, represents a flowering joint of a plant sent from Arizona by Dr. 

 MacDougal in 1902. 



