B U L L E T I N O F T H E T O R R E Y B O T A N I C A L C L U B VOL. 100, No. 6, pp. 353-356 NOVEMBER-DECE:MBER 1973 A new Centaurium(Gentianaceae) from the Death Valley regionof Nevada and California' James L. Reveal and C. Rose Broome Department of Botany, University of Maryland. College Park, Maryland 20742 and Janice C. Beatley Department of Biological Sciences, University of Cincinnati, Cincinnati, Ohio 45221 REVEAL, J. L., C. R. BROOME (Dept. Bot., Univ. Maryland, College Park 20742) and J. C. BEATLEY (Dept. Biol. Sci., Univ. Cincinnati, Cincinnati, Ohio 45221). A new Centaurium (Gentianaceae) from the Death Valley region of Nevada and California. Bull. Torrey Bot. Club 100: 353-356. 1973.-Centaurium namophilum spec. nov. is de- scribed from the Ash Meadows area of southern Nye County, Nevada, and adjacent areas of the Death Valley region in Inyo County, California. The new species is most closely related to C. trichanthum,but may be readily distinguished from the latter by its open paniculate-cymose inflorescence, narrow cauline leaves, and shorter calyx, corolla-tube and corolla-limb, and anthers. Both species have a chromosomenuimber of n - 17. Continued studies on the vascular up to 4 cm long, usually much shorteres- plants in the Ash Meadows regionof south- pecially above and on the lateral flowering ern Nye County, Nevada, and adjacent stems; inflorescencesusually more than portions of Inyo County, California,have half the length of the plant, paniculate- revealed another new species endemic to eymose, mostly trichotomouslybranched; this area. Past studies have shown that pedicels short,lacking or up to 4 mm long this part of the Amargosa River drainage in secondaryand tertiarydichasia, and up harbors a large number of highly special- to 9 mm long in the lower primary di- ized plants in several plant families (Beat- chasia; bracts minute, up to 1 mm long, ley 1971), and the discovery of a new opposite, becoming longer (up to 4 mm Centaurium (Gentianaceae) bringsthe list long) at the lowermostnodes; calyx tubu- of locally endemicplant species to ten. lar, 7-8 mm long, the (4) 5 segmentslin- ear-oblanceolate,united about 1/4the length Centaurium namophilum Reveal, of the tube, green with a thin hyaline to & Broome Beatley, spee. nov. opaque margin,the apex of each lobe acute A C. trichantho(Griseb.) Rob. inflores- and tan; corolla salverform,the corolla- centiispaniculati-eymosis, foliis angustiori- tube (6.5) 7-8 mm long, constrictedabove bus, linearibus, calycibus corollis et an- the ovary, greenishexcept for the yellow- theris brevioribusdiffert. ish portionjust below the petals, the petals Erect herbaceous glabrous annuals up deep rose-pinkabove and below except for to 4.5 dm high with floweringstems borne a broad whitishcentral band on the lower from the base with floriferous lateral surface, the throat of the tube yellowish branches, arising from a slender tannish with five dark purplish spots just below taproot; leaves opposite, not forming a the juncture of the two adjacent petals, basal rosette,linear to linear-lanceolate,up the corolla-lobes 7-8 mm long, (2) 2.5-2.8 to 5 cm long and 5 mm wide along th( (3) mm wide, ovate, the bud convolute; lower part of the stem, becoming shorter 1 The work reportedhere was conducted in part (to 1 cm long) and narrower (to 1 mn under U.S. Atomie Energy Commission contracts No. AT (04-1) Gen-12 and AT (11-1) 2307 and wide) above, the blade rigid with an acute in part under National Science Foundation Grant sharp and somewhatmucronate, brownisl GB-22645. The illustration was prepared by Dolly to tannish tip, otherwisegreen; stems yel- E. Barger. lowish- to tannish-greenwith internodes Received for publication June 14, 1973. 353 354 BULLETIN OF THE TORREY BOTANICAL CLUB [VOL. 10() stamens conspicuously exserted, the an- Prosopis pubescens Benth.) in the vicinity thersgolden-yellow, linear, 2.8-3.4 mmlong of springs or streamswhich dot the north- at anthesis,becoming twisted and 2-2.5 mm ern and eastern sections of Ash Meadows. long after pollen release; style slightlyex- In Ash Meadows, and in the other known ceedin-gthe stamens,6.5-7.5 mm long, the sites in the Death Valley region, C. namo- stigma slightly two-lobed, each lobe 0.4 philum also occurs on alkaline clay soils of mm long and wide; capsules, when mature, low uplands where some seepage water is narrowly fusiform,7-8 mm long, valves apparently available. On many of these elongatin-gto 11 mm long upon dehiseence; sites,it is associated with some of the other seeds black, rectangular,less than 50 per rare endemicspecies of the region: On the capsule, 0.7-0.9 mm long, minutelyreticu- drier sites it grows with Ivesia eremica lated; n= 17.-Restricted to spring areas (Cov.) Rydb., Cordylanthus tecopensis in extremesouthwestern Nye County,Ne- Munz & Roos and Cleomella brevipes S. vada, aid adjacent Inyo County, Califor- Wats., and on the wetter sites (especially ida; floweringfrom July to Septemberand in Ash Meadows) with Sisyrinchiumfu- fruitingto October. nereumnBickn. and Grindeltiafraxino-pra- TYPE: NEVADA: Nye Co.: Ash Mead- tensis Reveal & Beatley. It was probably ows, in moistsoil near spring at the "Col- presentuntil recentyears in most or all of lins Raneh," 1 km south of Devil's Hole, the spring areas of northernand eastern Death Valley National Monument, along Ash Meadows,but is today restrictedto the the Ash Meadows road, T.18S., R.50E., few such areas remainingwith vegetation see. 1 (sw 1/4),at 700 m elevation,25 July remnantsand free-flowingwater fromthe 1972, Beatley & Reveal 13447. Holotype, springs.The species is perhaps morewidely US! Isotypes, ARIZ, BRY, CAS, COLO, distributed in the Death Valley region DUKE, G, GH, K, MICH, MO, NY, OKL, than reportedhere. P, RM, RSA, SMU, TEX, UC, UTC, WTU Of all the North American species of and elsewhere. Also voucher for chromo- Centaurium (Dunn 1967, Broome, unpub- some number. lished), C. namophilumis most closely re- ADDITIONAL COLLECTIONS SEEN: CALI- lateci to C. trichanthum,a species found FORNIA: Inyo Co.: Bisting Springs Val- to the west in the coastal ranges of north- ley, 7 Feb. 1891, Coville & Funston 275 westernCalifornia and in the Central Val- (US); Furnace Creek, 17 May 1915, S. B. ley of that state. Both species have short- Parish 10035 (UC), Tecopa, 7 Aug. 1950, pedicellate flowerswith corolla-limbsmore Roos & Roos 4927 (RSA, UC). NEVADA: than half as long as the tube and small Nye Co.: "Collins Ranch": 22 July 1965, stigma-lobesless than 0.5 mm long and Beatley 3330 (DS, NTS), 8 July 1969, wide. The majority of Centauriun?species Beatley 9328 (NTS, RSA), 8 July 1970, (the exceptionbeing C. beyrichiiof Texas Beatley 11336 (DS, NTS, RENO, RSA), and Arkansas), and especially those of 14 Sept. 1970, Beatley 11741 (DS, NTS, California and the southwesternUnited NY, RENO, US ), 8 Oct. 1970, Beatley States, have longer and broader stigma- 11905 (NTS, RENO, RSA), 3 Oct. 1972, lobes which are distinctly divided, and Beatley & Anderson 13448 (DUKE, NTS usually more than 1 mm long. Likewise, -source of seeds for greenhousestudies); both have ratherlarge seeds, with those of southeast of Longstreet Springs, 22 July C. trichanthumbeing 0.5-0.6 mm long, 1968, Reveal 1623 (NTS) ; Big Springs, 29 while the seeds of C. namophilum range Aug. 1968, Reveal 1959 (NTS); spring from 0.7-0.9 mm long-the longest of all area northwestof Devil's Hole, 14 July species in North America. 1969, Beatley 9328 (NTS, NY, RSA); 0.4 The new species differsfrom Centau- km south of Big Springs, 22 Sept. 1971, rium trichanthurnin several features.The Beatley 13271 (NTS, US). infloreseenceof C. trichanthumis largely ETYMOLOGY: From the Greek nama eymose-umbelliformwith rather compact, (noun) = spring, and philos (adjective) = terminal,largely dichotomouseymes, while loving,as to the habitat. that of C. namophilumis paniculate with In the Ash Meadows area, Centaturium a more open system of trichotomousdi- namnophtlu,rngrows in wet Distchltismead- chasia at the upper nodes. Flowers are ows (with scattered Fraxinus velutina usually not present at the forks of the Torr. var. coriacea [S. Wats.] Rehd. and main branches in C. namophilum,nor do eG.~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Fig. 1. Illustration of Centaugriumnamophlumr showing general habit (A), a detail of a single plant (B), enlargemeirtof a flower (C), an arithershownr after pollenrrelease (D), and a camera-lueida draw- inrgof the chromosomecomplement (E). 356 BULLETIN OF THE TORREY BOTANICAL CLUB [VOL. 10( the flowersbecome conspicuouslyclustered The new species has pedicels less than at the tips of the upper branches. 9 mm long, while those of Centaurium In general,the size of all parts of Cen- exaltatumare usually morethan 2 cm long. taurium namophilum is slightly smaller, The inflorescenceof C. namophilum is but unlike C. trichanthutm,the corolla-tube broaderand moreprofusely branched, with at anthesis does not greatly exceed the the corolla-limbsof the flowermore than length of the calyx, and the throat of the half the length of the tube, whereas the flowers of C. namophilum lack the pro- corolla-limbsof C. exaltatum are less than nounced whitish area of C. trichanthum. half the tube-length.The style of C. namo- The anther length in all species of the philum is more than threetimes the length genus is pronouncedlyshorter after pollen of that of C. exaltatum, and the anthers release; however,in the twisted condition, are nearly twice as long. Furthermore,the the anthers of C. namophilum are 0.5-1 new species and C. trichanthumhave a nmmshorter than those of C. trichanthhum.chromosome number of n = 17, while C. ex- The leaves of Centauriuumnamophilutm altatum is an octoploid at n = 40.