532 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1908. 



rock " (Ariocarpus fissuratus) , growing on the hills of Perote. Echi- 

 nocactus {Astrophyton) capricomus (pi. 5, fig. 2) was also common in 

 this locality. A variety of E chinocactus hicolor (pi. 13, fig. 2) had 

 its spines most brilliantly variegated with red and yellow ; and a 

 hooked-spined Echinocactiis {E. uncinatus) bore a close resemblance 

 to E. longihamatns^ except that the flowers were purplish instead 

 of yellowish, the spines were more dense, and several centrals were 

 hooked instead of a single one. A distinction was here made be- 

 tween two species of Echinocereus, apparently E. conglomeratus 

 and a species with very long bluish sjjines. The first was called 

 " pitahaya de Agosto," because the fruit at this place ripens in 

 August, and the second was called " pitahaya de San Juan," be- 

 cause the fruit is expected to be ripe on Saint John's Day (mid- 

 summer). A cylindrical Opuntia, called " coyonoatli," was ap- 

 parently 0. imlyricata^ which I had already collected; but a second 

 more slender-branched species, bearing the name of " tasajillo," was 

 quite distinct from the Monterey tasajillo, since its fruit was 

 orange-colored instead of red and its branches somewhat stouter. 

 A little Echinocereus, related to E. pectinatus^ had its spines prettily 

 colored in such a way as to form zones of red and straw color, from 

 which it has been named " rainbow cactus." 



It gives me great pleasure to acknowledge here the courtesy ex- 

 tended to me by the Madero family during my stay at Parras, and 

 the kindly assistance of Dr. Alfred Walther, at whose house I found 

 Forster's Handbuch der Cacteenkunde, edition of 1892, illustrated by 

 a number of excellent woodcuts. Doctor Walther had established 

 a small collection of living cacti in the principal plaza of Parras. 

 Among the most interesting were G ephaloeereus senilis, called cabeza 

 de viej o, or " old man's head," from the gray hair growing from its 

 crest (fig. 15, p. 552) ; Eclvinocactus {Astrophytmyi^ myriostigma, the 

 birreta de obispo, or " bishop's cap," from Cerravola, a short distance 

 west of Parras; the closely allied E. {Astrophytum) cajjncormis from 

 a barranca just south of Parras (pi. 5, fig. 2) ; Echinocactus pilosus, 

 sometimes 4 feet high and 2 feet in diameter, with ruby-red spines 

 and white, radiating, twisted string-like hairs; Echinocer'eus 

 ccBspitosus (rainbow variety), and MamAllaria leona, from Llanitos, 

 9 miles east of Parras; the remarkable Mamillaria cirrhifera longi- 

 spina, covered with long, tangled spines like coarse, wiry hair, from 

 the barranca behind the neighboring Capilla; and the well-known 

 chilito-bearing Mamillaria meiacantha, with pyramidal tubercles 

 and short spines. 



But the most interesting cactus of this region from a botanical 

 point of view is Lenchtenbergia principis (fig. 23, p. 559) from Pata 

 Gallina, a short distance to the southeastward of Parras, where it 

 grows in company with Mamillaria scheerii and Opuntia cereifonnis. 



