New Combinations in Carex Section Acrocystis (Cyperaceae) J. H. Rettig Biology Department, College of the Ozarks, Pt. Lookout, Missouri 65726, U.S.A. William J. CrinsOntario Ministry of Natural Resources, P.O. Box 9(XX), Huntsville, Ontario PIH 2A3, CanadaABSTRACT. Carex communis and C. amplisquamacan be distinguished based on achene micromor-phology. However, similarity in macromorphologyand flavonoid chemistry suggest they are best treat-ed as two varieties of Carex communis. Carex ru-gosperma and C. tonsa are morphologically closelyrelated and are best treated as two varieties of asingle species. For reasons of nomenclatural pri-ority, the new combination C. tonsa var. rugospermais required. Carex tonsa also is lectotypified. Carex communis L. Bailey is a wide-ranging tax-on of eastern North America, whereas C. amplis-quama F. J. Hermann is restricted to northern Georgia and extreme western South Carolina. The most striking feature of C. amplisquama is the large pistillate scales. The two taxa are very difficult to distinguish, and some specimens assignable to C. communis based on other macromorphological characters have pistillate scales that approach the length of those in C. amplisquama. Principal component (PC) and cluster analysesof macromorphological characters revealed overlapbetween the two taxa; however, study of a discrim-inant function analysis resulted in complete sepa-ration (Rettig, 1988). Pistillate scales of Carex am-plisquama are significantly longer than those of C.communis (p < 0.001), although there is some over-lap (Rettig, 1988). Carex amplisquama also is al-ways densely caespitose with culms erect and arch-ing over at the tip, whereas C. communis is usuallyloosely caespitose with prostrate culms. This fieldcharacter ("lost" in pressing) is especially useful inseparating taxa when combined with pistillate scalelength. Ranges of 10 achene micromorphological char-acters examined in the multivariate study over-lapped; therefore no characters could be considereddiagnostic, although five characters were signifi-cantly different (Rettig, 1988). PC and cluster anal-yses show complete separation of the two taxa with-out any overlap: all individuals of Carexamplisquama clustered together before clusteringwith individuals of C. communis. Some plants of Carex communis produce Luteo-lin 7-Methyl ether 4'-diglucoside, a Luteolin 5-sub-stituted glycoside and a 5-substituted flavone gly-coside not found in C. amplisquama (Rettig, 1988). Multivariate analyses did not separate the two va-rieties into groups that correspond to morphological delimitations; however, C. amplisquama specimens were grouped together. Achene micromorphology provides the strongest evidence for two distinct taxa. However, similarity in macromorphology and overall flavonoid chemis-try suggest that they are best treated as two varie-ties. Carex communis L. Bailey var. amplisquama (F J. Hermann) J. Rettig. comb. nov. Basionym: Carex amplisquama F. J. Hermann, Rhodora 57: 158. 1955. TYPE: U.S.A. Georgia: Gilmer Co., J. II. Pyron & Rogers McVaugh 2951 (ho-lotype, US; isotypes, GA, MICH not seen). KEY o TO TE VAII~tt oF (,I. o 'at' riOunMs'IS la. Pistillate scale shorter than perigynium or ex-tending beyond the terigyniurn no more than 0.8 mm; plants usually loosely caespitose with lax culms ............ C. communis var. communis Ih. Pistillate scale extending lwyound the pwerigyniumn more than 0.8 am; plants usually densely caes-pitose with culms erect to arching ......... .............. co. nmmunlu var. amnplistquoma North American caricologists acknowledge Carexrugosperma Mackenzie and C. tonsa (Fernald)Bicknell to be very close relatives. The taxa differqualitatively in leaf texture, color, and indumrnt,and in the degree of pubescence of the perigynia.with C. tonsa having coriaeteous, light green,smooth leaves and perigynia that are virtually gla-brous. Fernald (190)2) was the first to combine thesetaxa at varietal rank, although at the time the typ-ification of C. umbellat Schkuhr ex W1illdent w hadnot yet been resolved (C. umbellata is now knownto be a related but distinct species with short perig-NovoN 6: 117-118. 1996.