CACTACER. SILVA OF NORTH AMERICA. 1 
OPUNTIA VERSICOLOR. 
Jornts of the branches dark green or purple, elongated, their tubercles flattened, 
elongated ; spines brown or reddish brown. Flowers green tinged with red or yellow. 
Fruit green, spinescent, rarely proliferous. 
Opuntia versicolor, Coulter, Contrib. U. S. Nat. Herb. iii. 452 (1896). — Toumey, Bot. Gazette, xxv. 121.— Schumann, 
Monog. Cact. 674. 
A tree, with an erect trunk occasionally in well-developed specimens six or eight feet high and 
eight inches in diameter, and numerous stout irregularly spreading often upright branches. The bark 
of the trunk and of the large branches is smooth, light brown or purple, usually unarmed, from one 
half to three quarters of an inch in thickness, and ultimately separates into numerous small closely 
appressed nearly black scales. The terminal joints of the branches are cylindrical, generally from six 
to twelve inches but sometimes two feet in length, and from three quarters of an inch to nearly an inch 
in diameter; their woody skeletons are usually formed during their second season, and they are covered. 
with a thick epidermis which varies from dark green to purple, and is marked by linear flattened 
tubercles terminating in large oval areole which are clothed with gray wool and generally bear a cluster 
of small bristles; their spines are slender, stellate-spreading, the inner from one to four in number, 
usually deflexed and unequal in length, the longest being about one third of an inch long and much 
longer than the radiant spines; they are brown or reddish brown, with close early deciduous straw- 
colored sheaths, and vary on young joints from four to fourteen in number, while the tubercles of old 
branches often bear from twenty to twenty-five. The leaves are terete, from one third to one half of 
an inch in length, abruptly narrowed to the spinescent apex, and remain on the branches from four 
to six weeks. The flowers open in May, and when fully expanded are about an inch and a half in 
diameter, with ovaries five eighths of an inch long, broadly ovate acute sepals, and narrow obovate petals 
rounded above and green tinged with red or with yellow. The fruit is usually clavate, from two inches 
to two inches and a half in length and nearly an inch and a half in diameter, with areole generally only 
above the middle and usually furnished with from one to three slender reflexed persistent spines about 
half an inch long, or occasionally spineless ; rarely the fruit is nearly spherical and only about three 
quarters of an inch in diameter. When mature the fruit is of the same color as the joints on which it 
grows and ripens from December to February ; usually it withers and dries on the tree and frequently 
- splitting open shows the irregular angled seeds with their narrow commissures. In some cases it does 
not wither during the first winter, but remains fleshy and adheres to the branch until the end of the 
following summer and sometimes through a second winter; or often it is imbedded in the end of a more 
or less elongated joint. 
Opuntia versicolor is the most abundant of the cylindrical Opuntias of the foothills and low 
mountain slopes of southern Arizona and northern Sonora, although it does not appear to have attracted 
the attention of botanists until 1880, when it was found in the neighborhood of Tucson by George 
Engelmann * and C. C. Parry? 
The wood of Opuntia versicolor is reticulate, hard, compact, light reddish brown and rather 
lustrous, with thin conspicuous medullary rays, well-determined layers of annual growth, and thick pale 
or nearly white sapwood.? 
1 See viii. 84. 2 See vii. 130. foothills of the Santa Catalina Mountains near Sabina Cation, is 
5 The log specimen in the Jesup Collection of North American five and seven eighths inches in diameter inside the bark, with 
Woods in the American Museum of Natural History, New York,  seventy-nine layers of annual growth ; of these twenty-eight are 
which was cut by Professor Toumey in southern Arizona on the of sapwood, which is three quarters of an inch in thickness. 
