rhytnlaqin ( IVhruarv 199(1) 681 2): 1 22 12 t. TWO NEW SPECIES OF .l/?r7//i^.lC'C//.l/Z/5 (ASTERACEAE: ASTEREAE) FROM OAXACA, MEXICO Guy L. Nesom Department of Botany, University of Texas, Austin Texas 78713 U.S.A. ABSTRACT Two new species of Archibaccharis sect. Archtbacchans from south central Oaxaca, Mexico are described: A. inacdonaldiland A. nepho-cephala. KEY WORDS: Archibaccharis, .Asteraceae. .Astereae. Mexico. Recent collections from south central Oaxaca by Dr. Andrew McDonald include a number of previously undescribed species, among them two species of Archibaccharis. Both are erect shrubs and members of sect. Archibaccharis, but they are only distantly related to each other within that section. Both are known only from the type collection. Archibaccharis macdonaldii Nesom, sp. nov. TYPE: MEXICO. Oaxaca: Cerro Quiexobra and vicinity, 35 km ESE of Miahuatlan. 5 km NE of Santo Domingo Ozolotepec, timberline vegetation in open glades along ridges and in mountain saddles, dominated below by pine forest, common on dry, ridge tops, SE exposure, 3650-3800 m, 10 Dec 1989, A. McDonald 2932 {liOLOTYFE: TEX; isotypes: F,MEXU,NY). A. hieracioides (S.F. Blake) S.F. Blake similis sed foliis multo minoribus paucidentatis, capitulis minoribus, et corollis pistillatis ligulis brevibus differt. Woody, erect shrubs. Stems 1-2 m tall, the upper highly branched atid dark purple-brown. Stems, leaves, and phyllaries moderately to densely in-vested with short stipitate resin glands, the stems also sparsely villous. Leaves densely arranged, obovate, basally attenuate to a subpetiolar base, not clasp-ing, 6-16 mm long, 3-7 mm wide, with 1-3 pairs of coarse teeth, thick tex-tured with the upper surface somewhat shiny, glandular but otherwise glabrous or with a few, scattered hairs. Heads campanulate-turbinate, 3-4 mm wide, on wiry pedicels 7-15 mm long, in distinctly flat topped corymbs; phyllaries oblong-lanceolate, purple tipped, graduated, the inner 1.0-1.5 mm long, with 122
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