CACTACEjE. 661 



armed with 12 to 16 stout, almost conical, straight spines, the 3 to 5 

 inner ones the stoutest, 4 to 6 or 6 to 8 lines long. The grooves 

 between the ribs are very narrow, acute and not deep. Of no°species 

 of this section do the flowers appear to be known. The following 

 description of the flower figured by Mr. Agate, therefore, supplies a 

 desideratum.— Flowers 5 inches long, sessile above the areola, and 

 in the transverse incision between the tubercles; the tube curved 

 upwards, over 3 inches long, gradually enlarging above ; the limb 2 

 inches in diameter; ovary subglobose, horizontal, 9 or 10 lines long, 

 densely imbricated with nearly a hundred sepaloid scales; sepal's 

 about 100, imbricated on the tube, the lower triangular, the upper 

 successively becoming larger and lanceolate, greenish, with the apex 

 somewhat reddish; about 15 of the uppermost ovate-lanceolate, acute, 

 tipped with light reddish-brown; petals 15 to 18, ovate, mucronate, 

 4 or 5 lines wide, white." Engelmann, Ms. 



There are no specimens of Cactacece in the collection, except an 

 imperfect sterile branchlet of some Opuntia from Rio Negro, North 

 Patagonia, which is undeterminable. In his manuscript list, Dr. 

 Pickering enumerates twelve species as having been noticed at Rio 

 Janeiro ; viz. one Melocactus, five Gerei, one Epiphyllum, one Opuntia, 

 a Pereshia, and three species of Rhipsalis. At Rio Negro, three 

 Opuntice, a Gereus, and a doubtful Mamillaria. In Chili, besides the 

 Gereus Gkilensis, two Echinocacti and an Opuntia are mentioned. In 

 the tropical region of Peru, from Lima to the Cordilleras, a Melocactus, 

 four or five Gerei, and as many Opuntioe are noted ; and three or four 

 others are mentioned as growing in the western Cordillera region, 

 from Obrajillo to Culnai. Among these, one of doubtful genus: 

 having a slender and upright trunk, 8 or 10 feet high, with spreading 

 branches at the summit, distant clusters of long spines, and large, 

 dry, and stony seeds. A second species resembling the last, but 

 lower (8 inches high) and less woolly, with smaller fruit, is mentioned 

 as occurring in the pampas or pasture region of the Cordilleras, two 

 and a half leagues above Culnai. 



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