NEW WORLD JUGLANDACEAE: A NEW SPECIES OF ALFAROA FROM MEXICO

Alfaroa mexicana is described as new. Certaini aspects of the wood anatomy, inflorescenice, pollen, staminate flower, and pistillate flower morphology are compared with previous findings on the three other species of Alfaroa and representatives of the closely related genus Engelhardia. ONE OR MORE species of Carya, Engelhardia, and Juglans have previously been reported from Mexico. Collections from the vicinitv of Volcan de San Martin, Veracruz, that were identified as Engelhardia mexicana Standley (Miranda 8368, 1\IEXU) and E. guatemalensis Standley (Andrle 1, US) have been reexamined and augmented by more complete samples and found to be members of a new species of Alfaroa. Mexico is now recognized as having representatives of all four of the New World genera of Juglandaceae. The Mexican collections which are herewith assigned to the genus Alfaroa are from the relatively isolated volcanic uplift that parallels the coast bordering the Golfo de Me\xico at lat 18.50 N, long 950. La Sierra de los Tuxtlas formation is up to 15 miles wide and 45 miles long with a maximum altitude of approximately 1400 m. There are three major peaks: Volcain de San Alartin (ca. 1400 m), Volcan de Santa MLarta (ca. 1400 m), and San MIartin Pajapan (ca. 1200 m). The flora of this area is poorly known. To my knowledge there are no collections of any Juglandaceae from Pajapan and but one collection of a shrubby growth-form of Engelhardia mexicana Standley (Ross 55, US) from the elfin forest of Santa M\arta. Volcan de San M1artin has at least two members of the Jug' Received for publication 26 July 1967. This work was made possible by the generous support of the National Science Foundation, grants GB-2313 and GB-5233X. The author thanlks the botanists at Universidad Nacional Autonoma de Mexico and especially Mario Sousa S. who first guided me to VolcAn de San Martin identified some of the associated vegetation, and confirmed the names and altitudes of the Tuxtla formation. Dr. Richard A. White, of Duke University, accompanied the author on the 1965 trip, and Mr. James A. Walker, of Harvard University, in the spring of 1966. Drs. Frederick A. Wolf and William Louis Culberson have graciously provided the Latin diagnosis. The manuscript has benefited from several suggestions by Drs. Charles Heimsch and Robert L. Wiibur and the expert advice and critical comments of Wayne E. Manning. The illustrat ons were drawn by Susan Carlton Smith. To these many people and organizations and to the curators of the US and MEXU herbaria, the author extends his deep appreciation. landaceae: Juglans (probablv J. pyriformis, W. E. M\ianning, personal communication), and the new species of Alfaroa. 'Most of the lower slopes ot the south side of San Miartin have been cleared but at mid-elevations some Alfaroas (3 ft dbh) are left standing in the fringes of clearings. Associates on the southern slope include Celtis, Juglans (Miranda, after W. E. Mlanning, personal communication), Liquidambar, Quercus, Saurauia, Talauma, and Trophis. On the moister and undisturbed northeastern slopes at 1100 m elevation, Alfaroa is locally abundant and found in association with Oreopanax, Hedyosmum, and Ardisia. Alfaroa mexicana Stone, sp. nov. (Fig. 1-15)Arbor usque ad 35 m alta. Folia pinnata decussata; foliola 8-12 (-18), coriacea, elliptica vel oblongo-lanceolata, ca. 7.5-17.5 cm longa atque 1.4-4 cm lata, basi asymmetrica et indumento in pagina inferiore dense instructa, basi marginibus revoluta, petiolulis 4-8 mm longis. Amenta masculina terminalia in inflorescentiis masculinis vel lateralia in inflorescentiis androgynis, amenta feminea terminalia in paniculis androgynis. Flores masculini parvi (2-3 mm lati) bractea 3-lobata et perianthio 4-partito instructi, staminibus 8-12. Flores feminei, perianthio 4-partito, ovario infero, stylo obsoleto, stigmate subgloboso. Fructus ca. 5.5 cm longus, 3.7-4.2 cm in diametro, exocarpo porcato. Semen hypogaeum germinatione. All specimens examined were from the state of Veracruz, Mexico, as follows: Volcan San Martin, 8 mi n of San Andrs large tree in primary forest (cleared), 1 m dbh, 100 ft tall, buttressed, green fruits, 2.5 mi n of Volcan, on ridge, alt 2,400 ft, 26 April 1962, Andrle 1 (5?; US); 3 ft sapling, rich deciduous forest on s slope, midelevation, 30 January 1965, Stone 1879 (DUKE); 4-5 inches dbh, 20-30 ft tall, bark tight, just below rim of crater, alt 1,000-1,200 m, 30 January 1965, Stone 1880 (DUKE); seedlinigs and sap-