OPUNTIA. 



169 



come from Mexico. From the description it may belong to our series Dilleniaunc, but we 

 are unable to associate it with any species known to us; the ovary is described as com- 

 pressed and tubercled. 



OPUNTIA ANAHUACENSIS Griffiths, Bull. Torr. Club 43: 92. 1916. 



A low, reclining or prostrate plant, up to 5 dm. high, 1.5 meters broad; joints obovate, glossy, 

 yellowish green, 27 cm. long, 13 cm. broad; spines yellow or becoming white, i or 2, porrect, flattened, 

 twisted, 2 or 3 cm. long; flowers yellow; style white; stigma-lobes 6, white; fruit dark purplish red, 

 pyriform, 7 cm. long. 



Type locality: Anahuac, Texas. 



Distribution: Known only from the type locality, at the mouth of Trinity River, 

 eastern Texas. 

 OPUNTIA MEGALANTHA Griffiths, Bull. Torr. Club 43: 530. 1916. 



A tall, erect, open-branching plant, 2 meters high or more; joints obovate, glaucous, grayish 

 green, 21 cm. long, 14 cm. broad; spines yellow, i to 3, or even 5 or 6 on old wood, the longest often 

 4 to 5 cm. long; flowers yellow, 10 to n cm. in diameter; petals 5 cm. long, obovate; style white; 

 stigma-lobes 8 or 9, white or tinged with green; fruit dark red. 



Known only from cultivated plants received from the Berlin Botanical Garden, where 

 it was grown as Opuntia bergeriana. 



Series 16. MACDOUGALIANAE. 



Erect, mostly tall species, with flat, broad, 

 and thin, persistent joints, the epidermis, at least 

 that of the ovary, pubescent or puberulent. The 

 spines, when present, yellow. There are about 

 half a dozen species, natives of central and 

 southern Mexico. 



KEY TO SPECIES. 



Joints merely finely puberulent or 

 glabrous; spines 1.5 cm. long or 



less; ovary velvety 184. 0. durangensis 



Joints distinctly pubescent ; spines 



2 to 3 cm. long. 

 Petals red. 



Style shorter than the petals 185. O. atropes 

 Style as long as the petals. 186. 0. affinis 

 Petals yellow. 



Spines acicular, at first yel- 

 low, soon white 187. 0. macdougaliana 



Spines subulate. 



Petals retuse; areoles of 

 ovary many, approxi- 

 mate 1 88. 0. velutina 



Petals mucronate ; are- 

 oles of ovary few, dis- 

 tant 189. O. wilcoxii 



184. Opuntia durangensis Britton and Rose, 



Smiths. Misc. Coll. 50:518. 1908. F,G. ,08,-Opuntia durangensis. Xo. 4 . 



Joints broadly obovate, about 20 cm. long, 



16 cm. broad, pale green, glabrous or minutely puberulent, bearing numerous areoles; areoles i to 

 2 cm. apart, elevated; spines 3 to 5 at an areole, short, 1.5 cm. long or less, pungent, spreading, 

 yellow, but in age becoming darker; glochids brown, 2 to 3 mm. long; flowers yellow, 5 cm. long; 

 petals broad, apiculate; ovary 3 to 4 cm. long, finely pubescent, bearing many areoles with numer- 

 ous glochids and a few spines; fruit white or red; seeds about 3 mm. broad. 



Type locality: Near Durango, Mexico. 

 Distribution: Central Mexico. 



This species was collected by the late Dr. E. Palmer in 1912, but he did not record 

 the size and habit of the plant. The joints suggest a large, bushy species. 

 Figure 208 represents a joint of the type specimen. 



