548 ANNUAL EEPORT SMITHSONIAN INSTITUTION^ 1908. 



and O. durangensis and O'.leucotricha^ which bear the tunas duraz- 

 nillos of Durango and central Mexico. 



Criniferse, with long wool growing from its areoles, including the 

 nopal crinado of the State of Puebla {Ojmntia jnlifera). 



Vulgares, prostrate plants unarmed or with a few spines, includ- 

 ing our own little j^rickly pear of the eastern United States {O-puntia 

 opuntia) . 



Subinermes, upright plants scarcely armed at all or even spineless, 

 including the nopal cle tuna Castilla {Opuntia ficus-indica) , now so 

 widely spread about the Mediterranean and in troj^ical America ; the 

 various varieties known as " tunas mansas " (" tame prickly pears '") 

 in Mexico; and the tuna camuesa {0. larreyi), cultivated about 

 Queretaro. 



Setispinae, low plants with small joints and fine bristle-like spines, 

 including Opuntia fllipendula and 0. setispina of Texas and 

 Chihuahua. 



Tunae, bushy plants, often with abundant yellow spines, including 

 the common prickly pear of Texas and Tamaulipas {0. lindheimeri) , 

 the cuija {0. cuija) of northern and central Mexico, and 0. tuna 

 of the West Indies and gardens of Mexico, with edible red fruit and 

 yellow or red flowers. 



Fulvispinosse, bushy or sj)reading plants with brown or partly 

 brown spines and fleshy fruits, including nopal cle raiz of the Alvarez 

 Mountains {O. megarrhiza) , 0. engelmanni of northern Mexico and 

 Texas, and 0. arizonica (pi. 10, figs. 3 and G). 



Albispinosse, robust plants with white spines and broad petals, 

 including the tuna cardona {Opuntia streptacantha) of San Luis 

 Potosi, from which such enormous quantities of " tuna cheese " are 

 made. 



Stenopetalse, large white-spined plants with narrow petals, includ- 

 ing Ojnmtia stenopetala^ which was first collected on the battlefield 

 of Buena Vista, south of Saltillo, Coahuila. 



The flowers of Opuntia (pi. 10, fig. 3) are for the most part yellow 

 or orange, but in some species they are rose colored or crimson. One 

 of the loveliest is the rose-colored flower of Opuntia hasilaris of the 

 southwestern United States. In all cases the perianth opens widely 

 and the stamens are not so long as the petals. These features serve 

 to distinguish the Opuntia from the closely allied genus Nopalea. 

 The fruit (" tuna ") of many species and varieties of Opuntia (pi. 9, 

 fig. 6) is edible and is an important food staple." The young, tender 

 mucilaginous pads are cut into strips (" nopalillos ") and cooked like 

 string beans, and the pads (" pencas ") are also extensively used as 



o See Griffiths, David, and Hare, R. F. The Tuna as food for man. U. S. 

 Dept. Agr., Bur. Plant Industry Bui. 116. 1907. 



