rACIIYCKKRUS. 



7i 



below, densely tomentose (grayish except in flowering ones, which are brownish or reddish); spines 

 8 to 12, i to 3 central, all short, usually i cm. long or less, but in some cases 3 cm. long, grayish 

 with black tips; flowering arcolcs not much larger than the others; flowers 5 to 7.5 cm. long; ovary 

 covered with dense soft hairs with only a few bristles or none; outer perianth-segments purple, succu- 

 lent; inner ones white, fleshy; stamens very numerous; style with 10 linear stigma-lobes; fruit 6 to 

 7.5 cm. in diameter, dry, covered with yellow wool and long yellow bristles. 



Type locality: Hacienda San Miguel, Chihua- 

 hua, Mexico. 



Distribution: Chihuahua, Sonora, Colima, and 

 Lower California. 



Illustrations: Contr. U. S. Nat. Herb. 5: f. 32 ; 

 pi. 57, 58; Gard. and For. 7: f. 54; Diet. Gard. 

 Nicholson Suppl. f. 233, all as Cereus pecten-abo- 

 riginum. 



Figures 105 and 106 are copied from the two 

 plates first cited above. 



4. Pachycereus (?) gaumeri sp. nov. 



Plant slender, 2 to 7 meters high, erect, simple or 

 few-branched ; branches 4-angled or winged ; ribs thin, 3 

 to 4 cm. high; areoles large, 1 to 2.5 cm. apart, brown- 

 felted; spines several, slender, 1 to 3 cm. long, brownish; 

 flowers yellowish green, 5 cm. long; scales of the ovary 

 and flower-tube more or less f oliaceous, drying black and 

 thin, with brown felt in the areoles; scales on the ovary 

 linear, puberulent; fruit not known. 



This species is based on two collections, both 

 made in Yucatan by George F. Gaumer, as follows : 

 No. 23778 at Hodo, April 1917 (type), No. 648 

 at Port Silam, 1895. Dr. Gaumer writes of these 

 numbers as follows: 



"As to my No. 23778 I sent many fine specimens 

 of flowers and several cross-sections of a moderately 

 large plant to Dr. Millspaugh. It grows erect, has few 

 branches, many flowers on each plant; it is very com- 

 mon at the senote Hodo where the most of the plants 

 range from 6 to 10 ft. high ; it is a delicate-looking Cactus 

 of a light pea-green color, quite showy, the flowers are of 

 a light green tinged with cream-color, they do not open 

 out much but remain almost cylindrical. Living speci- 

 mens were sent to Dr. Britton at Bronx Park. It blooms in May and is found about four leagues 

 east of Izamal. 



"648 was taken by myself at the port of Silam in 1894 and sent to Dr. Millspaugh. Only 

 two plants were seen; one was about 10 ft. and the other 20 ft. high. It grows erect and the larger 

 plant had but one branch. My son Geo. J. has failed to find it in the region of Progresso." 



Since the above description was written, Dr. Gaumer has sent another plant (No. 

 2 3935) which we believe belongs here, although it differs somewhat from the other plants. 

 A cutting was sent to the New York Botanical Garden which produced a bud in the spring 

 of 1919, but this only partially developed. This plant may be described as follows: 



. — Pachycerei: 



pecten-aboriginum. 



Erect; ribs 5 to 7, separated by broad intervals; areoles 1 cm. apart; spines about 15, 

 cm. long, weak, gray in age; flower-bud acute, ovoid, covered with green imbricating scales. 



to 3 



