SIDA, Contributions to Botany
THE GENUS HESPEROYUCCA (AGAVACEAE) IN THE WESTERN UNITED STATES AND MEXICO: NEW NOMENCLATURAL COMBINATIONS
Karen H. Clary 1
>\ cm. i \gavai cue J consisting ol il
morphological, phenological and p at DNA analyses. Hesperoyucca wl
ili ,t i i li morfologicos, fenologicos \ I pnlmi^ d.ii ion nli k ioih bmuxnin ni ih luium
s. ADN. Hcspcw\ULLd innsia
1 is ]mi It 1 i 1 \ \ \ \ // , 111 1 ul 1 combinaciones nut\ piu Hi n / | unman
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Within Yucca L., as traditionally circumscribed, is a group of species, herein recognized as Hesperoyucca (Engelm.) Baker, that has morphological, pheno- logical, and pollinator characteristics markedly different from all others. These characteristics include a loculicidal capsule, a capitate stigma, and glabrous, swollenfilamentstli.il u uu< lu*d loth lm\< r p ut ol ih< t pals and that draw away from the ovary when the tepals open. These filaments bear bulbous an- thers with tufted pubescence that bend toward the stigma and dehisce later- ally (Fig. 1). Their pollen is produced in a glutinous mass. The sole pollinator of
Hesperoyucca is Tegeticula maculata Riley, a species of yucca moth (Riley 1892; Trelease 1893, 1902; Powell & Mackey 1966; Davis 1967; Segraves & Pellmyr 2001). The other approximately 47 species of Yucca are visited by the remaining spe- cies of yucca moth (Pellmyr 1999). In Yucca, the pollen is not agglutinated, but produced as single grains, nor are the filaments tufted. Furthermore, the stig- mas are not capitate, but divided into three lobes that spread outward. The pu- bescent filaments are appressed to the ovary and angle outward and when the tepals open. Recent analysesof DN A markers, including i he internal t ransci ibed spacer region (ITS)of nuclear ribosomalDNA and chloroplastHNACcpDNAXHanson 1993; Bogler 1994; Bogler & Simpson I99A 1990: Clary 1997) support the recog-
nition ol these uriu|iie species as members A a separate genus. Cmprawiuru
(Fngelm.) Baker. In the pbvlogenciic parsimony and maximum likelihood trees from DNA analyses these species \o\ m a branch that is sister to Hesperaloe
} (Agavaceae)and not Yucca (big. _ ). rlcsj>ctij,loc Fngelm. mcludesa group ol live species found in the Sonoran and C 'Jiihuahuan Deserts a! lied taxonomically as close relatives to both Agave b and iiu<
The group in question, Hkaprnn ie < a, corresponds to hngclmanns i. 1871 I
Yucca group Hespero via cm which ranges from California and Arizona to hap.
California Norte and Sonora in Mexico In this paper. Hcspcmviu \ a is recog- nized at the genus level, requiring two new species combinations. A raxonomic treatment of the genus will be published in Flora of North America.
While taxononn i working with Vurcuhavi recogni ed the members ol
the Hesperoyua a gro up. i ; distinctive from thcothei Via eu species, they have not
agreed on infrage nio. md inh isp< cilim in urn < i iption ! Iu laxa within Uespero- _yucca have been classified primarily bygiowth lornusingle or multiple rosettes), leaf morphology and whether the plants ate monocarpic or polvearpic. Most o^l the disagreement centers on the significance of morphological variation in Y whippki Torr. populations in Arizona and California (Trelease 1893, 1902;
Haines 1941; McKelvey 1947; Webber 1053; 1 lochstatter 2000). Within Yucca whipplei, Trelease (1893) recognized two varieties, Haines (1941) and Munz (1968) each recognized live subspecies and Webber (1953) rec- ognized four variet i< Others argm thai uowi i lorm is a highly variable char- acter and question the recognition ol varieties or subspecies at all (McKelvey 1947; McKinney & Hickman 1993).
McKelvey (1947) described Yucca newberryi from Arizona and Y. peninsularis from lhe Vizcaino Desert region in Baja California Norte. Webber (1953:33) believed leal, inflorescence and capsule features used by McKelvey to separate Y.newben xi bom V. whipplei wen- weak' and wit Inn the normal varia- tion of Y whipplei. HochstatterQOOO) included Y. newberryi asa subspeciesof Y whipplei. Supported by distinctive morphological characteristics, unique species ranges and ITS DNA analyses (Clary 1997), three species o\' Hesperoyucca are here recognized: R whipplei, H. penin.su/uris (McKelvey) Clary, and H.
newberryi (McKelvey) Clary. A key to t he species follows.
The ITS DNA analysis of Yinai, 1 lespetoxiu < a, Agave and / /espciu/nc (Clary 1997) included single individuals from lour tlcspcroymca populations: H. whippki from Sierra Viejo, Sonora, Mex ico (Bogler & Simpson 1996), and from San Diego Count)'. California: H. penin.su/uris from Catavma, Baja California m
Norte, Mexico; and H. ncwbcrryi from Mohave County, Arir.ona. The results show each of these samples to be genetically distinct from the others (Clary
1997). The other taxa attributed to H. whipplci \Y. whipplci subsp. caespitosa
(M.E.Jones) A.L.Haines, V. whippki subsp. percursa A.L.Haines, H. whippki subsp. intermedia A.L.Haines, Y. whipplci subsp. typicu A.L.Haines, and Y. whippki subsp. parishii (M.E.Jones) A.LJ iamesl were not sampled. Results of the phylogenetic (parsimony and maximum likelihood) analy-
< I i.le sis dum aiued i;> 'ju it hi In H. pt >m iu a < pht into two brancht vOik branch contains H. newberryi, basal to the lineage, while the other branch con- tains H. peninsu!(ins. which is sister to a branch that contains both H. whippki populations. These data support specific status for H. peninsularis and H.
nc wherry i. but not the two /J. whip/dei populations since they share unique mutations (Clary 1997).
i Recognition of infraspecific taxa wit i H nemvuee a whipplci beyond the scope of this paper. Although the taxonomic treatments of H. whipplei
\i within the above-t d wm In i \ ml e,n< iimi moi phological characters that separate taxa within jfi whipp] i, th« treatments, with the exception of McKelvey's (1947), lack sufficient records of specimens seen to evaluate the hypotheses about the proposed nature of variation within Y. whippki. Further systematic study of informative morphological characters and DN A of all taxa of Hesperoyucca is warranted to elucidate its entire phylogeny and determine the genetic relationships thai underlie the taxonomy of this group.
KEY TO YUCCA AND THE THREE RECOGNIZED SPECIES OF HESPEROYUCCA
1. Capsules s cidafthe seeds disp ersing laterally through openings at 1
• • or spongy; seeds ultimo- 1 Ilc
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1 i nl. i I |. , linn .i |, u id il ih. I cii |n no latei ill\ through frin d
( ) ,i ii I M i I ii i ii is . . , nHl sh| t, h it, iii h<. mi a- rt
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. I < • i Ii , im< J i I i I- i uill long and slender, to 0.7-2.0(-2.5) cm wnO aouw r i ' I I I I i i il t i i i I I | -n- 4 I in ill i . Idtun it. .u . nli ir.fiicuous placental wings; plants with s.mjlc i I I i i ii ii Ml in nultii i u ii hi i liluini d nl n 1 hi i .i 1 1 in Sonora , Hesperoyucca (Fngclm.) Baker. Bull. Mi.sc. lnlorm. Kew 1892lol):8. 1892. Yucca subtil. H t -.sp'N.vikLtHt-:nj;dinjRakiT.tiard.c:linin.n.s. 0:1%. 1S70. Based on VumUwithout rank; / h's/UTUVK. ( d Fnt>elm. in S VVals. cl al., Hoi any Horticih parallel!: 407. 1871 as limup 2: iii'si'i -ko-viu i A. Vurai Sect Hfs/'nimi.ui a-n Sdm.l in McKclvcy. Yuccas Southw. U.S. 2:14. L947 TYPE: rucca whipplei Torr. in Ives. There is disagreement regarding am horslup ol the genu:. 1 Icspcroyucca. Engel- : iiiaiin llo/'l J in i , divided Vu< id to two niajoi groups: l o > a and I Iespero-YUCCA, die Unnerve it h l hive iibgrouaps: Uuvocarpa t lisroeai pa a. nd ( haenocarpa. His group Hesperoyua« con lamed only Vitrc nus to Engelmann's Hesperoyucca recognizing within it a single species, Yucca whipplei. Greuter et al. (1993) and Greenhouse and Sirother (in press) accept this as legitimizing kngclmanris Hesperoyucca as a subgenus. In 1892, Baker noted that Y. whipplei, "had better be kept as a genus distinct from Yucca, un- der hngelmanns name Hesperoyucca" but he still listed the species as Yucca whippku (sic.) Torrey. Greuter et al. (1993) accept this as having erected the genus Hesperoyucca. (Engelm.) Baker in 1892. Greenhouse and Strother (in press) following ICBN Art. 34.1 (Greuter et al. 2000), do not accept this as creating a 1 new genus as Baker 1 pecii > redth Yucia\ hipplei 1 thusdid not accept the new combination. Trelease ( 189 V.208)aci epied Bakei sU892) suggestion of thegenus rank for bfe.s]Ha-()V!i((Ai,foiuiiall\'t'eeog,riieiiig//es/-er()vutcaatthesame rank as, and separate from Yucca, and distinguishing Hesperoyucca from the "true Giec.is." The combination Hesperoyima wl\ipj>lei appcais in the list of illustrations, in the Explanation of [dates (Trelease 1893:21 T) and as the generic name of variety graminijol la ( Trelease 1893:21 ;. tt. 17 & 23). This is considered by Greenhouse and Soother Un press) to be the first legitimate use of the name ol the genus Hex/urn via ru I Iowever. Bakers U8°U) mere suggestion in print of generic rank for Hesperoyucca is accepted bv Karnes m i in rent Use (Grueter et al. 1993) and by Flora North America (FNA) to be the first valid use of Hesperoyucca as a genus, not Trelease s (1893) taxonomie description. Distribution -U.S.A. California. Arizona. Mexico. Baja California Norte, Hesperoyucca whipplei Con ) Baker e.\ Trek. ,\ n n. Rep. Missouri Bot. Card. 4:208. 1893. (Fig. I). Basionvm Yucca hi lci W rP Torr ,n |C Ives. Rep ( olorado R 4 (Bot J:2C 18bl. Typo U.S.A. CM. 1TORNIA Sa\ Diruo Co.: San kasqual. A.SduHt vii.u n uhyiv \Y!) The . a whippier. A. Growth habit, showing basal leaf rosette and inflorescence [from p rom Nichols B-4-21 -92 (TEX), and p by Constance & Morrison 2269, 1 150192 (MO)]; C. Capsule, showing fringed placenta septa margins and loculicida hiscence [135741 (MO)]; D. Capitate stigma, showing papillae on stigma surface [from Nichols B-4-21 -92 (TEX) photo by Constance & Morrison 2269, 1150192 (MO)]; E. Stamens showing cordate anthers and tufted pubescence [I Nichols B-4-21 -92 (TEX [0 by Constance & Morrison 2269, 1 1 501 92 (MO)] ited"il itpnjve to be a distinct species it mav he called Y.whipplei." Gr isider Torrcv's name as provisional and not validly public ( N [Mhluh.-. 1 in Ives' "Report upon the "olorado River ot the west" (To UggCSled 1 hat the species should be recognized within Hesperoyi ..llwx^.iitzed hiespavyucca as a genus, and 1 Icspcwyucca wlupplci i it, 7, ITS 1 & 7 strict consensus tree of the 10,777 most parsimonious 467 step tn Rl=0.846). Step changes are written above branches, with bootstrap percentages > 50 % written below (Clary 1997). Samples of Agave striata, Hesperaloe parviflora, Hesperaloe funifera, Hesperoyucca whipplei (Sonora, Mexico) are from Bogler(1994,1996);samplesof««pera/oenocfumfl,tfe5peroyura^ forma), Hesperoyucca newberryi and Yucca L. are from Clary (1997). 'emyuccawhippleiC -n California." Torrcx :r. ] April, growing n Ucspciv\-uuu whippla vai. vnmimi/Wu/ Tief. TYP1-: U.S.A. CALIFORNIA. Los ANt.H.Ls (.\\: Mountains 12 mi L. o il GH. Greenhouse and S> ii L>x) Jones, r. ivw. , ME. Com YV Hot. Vn, ,, ,Wn rr ln siibsp. ,>,n is/iii s. Madrono 6:44. 1941. Typi:: No specimens were cited by Jones (1929). this taxon as "the common form at low clev.il ions on the Pacific slope, i the desert side." Haines 1 1^41) gave the lot ai ion of the type (California: ( > IMi |Q lit a M, , uh Vu , L iv,i,,pplnx u uu\immiM.I lorn nun MM-> g y , M' Y>: 1041 U.S.A. (M.HJoncsj A.I.. I lames, Madrono 14 .Tvi'h: CALIFORNIA 1 ' 1 1 l^iTYPP ; Cactus Hal in C uishenbui \ C am on. 12 Mav ICM, joins sai. 1 iOla YIT: PCM CAS) var. mlcrmedui Viici-n iv/iipplt-j subsp. imcrmedia A.I.. I lames, Madrono6M3. t94f. Yucca whipplei (A.L. Haines) J.M.Wcbbcr. Miccas southw 54. AMI Aypis C.S.A. CALIFORNIA. I .OS ANGF.l.l-s I opM)| 1 (piioio, Q Malihul.ak. intaMoni, Mountain Jun IsHO, / Mm n.[i k>K> Yl'lH A i i-l, I 1 s I 1 var Yuccawhippleimbsp piHiusa \ 1 lauu Ma 1 ( Haines) J.M. Webber.Mice; ouili M A>'M. AvisM) VCAIJFMkNI hii 1 no authentic material. A neotype may be designated after further study. Distribution—USA. California: San Diego, Orange, Riverside, San Bernardino, Los Angeles, Ventura, Santa Barbara, Kern, San Luis Obispo, Tulare, Monterey, San Benito counties; Mexico. Baja California Norte: Municipio Ensenada, Mexicali;Sonora. Hesperoyucca newberryi (McKelvey) Clary comb. nov. BASIONYM: Yucca newberryi >lci suhsp (McKelvey) McKelvey, Yuccas Southw MS. 2:40. FM7. Ma, si wl,i P] newberryi !s I l l H hi den Vthc 1.1 » 000 1 I A \l I \ 1 M Hesperoyucca peninsularis (McKelvey) Clary, ( Distribution-Mexico. Baja California Norte. Matuda and Pina-Lujan (1980) consider Yucca whipplei subsp. eremica Epling & A.L.Haines to be a synonym of Y. peninsularis. The original collections of each species are from the c.mearey 10 F of, and 13 milesSI ol F.l Rosario. Com- parisons of habit and leaf morphology in the original descriptions (McKelvey f947; Epling & Haines 1957; Matuda & Pina-Lujan 1980) and of both live and vouchered specimens at TEX indicate that both belong to the same species. ACKNOWLEDGMENTS I thank James Zarucchi (MO), Victoria Hollowell (MO), William Hess (MOR), Beryl Simpson, James Hennckson and Tom Wendt (TEX), John Strother (UC) for helpful comments on the manuscript. Photocopies of specimens were pro- vided by Lee Lenz (POM) and Barry Prigge (LA). 1 thank the curators of UC, POM, DS, GH for specimen loans. David Bogler (MO) provided photographs and was an advisor for the illustration (Fig. 1) drawn by Bee Gunn (MO) and Yevonn ri:i : 1'R]-:nc:hs BakirJ. 1876. New garden piants.Gatd.c hron.n.s. 6:196-197. form. Kew 4(61 ):1 -10. in Bogii-r, D. 1994 1 ] on it 1 h ifi [i n i ] i In [[ Dissertation. The University of Texas, Austin. "> Si i i 1 i BocifR.D.andBB \ hi I ( I if i | U Hh Ui ie Syst.Bot.20:191- 205. B(x.,i i.r, D. and B.B. Simi-, .n. 1 99b. Phytogeny of Aqavac eae based on ITS rDNA sequence iiv,mii CiRi mi r,W„ R.K. Bri i, P. I ['.< ark., . N. Kn ian, P.M. Kirr, and s ira, 1 003. Names in current use lot ext ml pi inl jet ta.ReqA j. 1 ' 2 1 I ' I i ' I , < 'I Ihloq. Ih R I. II , hit ^TltlOli ui h|, H, || ,iR|, ,i n 11 I )i in! ii t I fi it i i | i it t ii i | i tnnscribed spacer (ITS) region of the nuclear ribosomal DNA. Ph.D.Dissertation.The University of Texas, Cohriii, D.S. and MG. Johrroon. 1979. Manual ol the vascular plants of Texas. Texas Re- search Foundation. Renner. Davis, D. 1967. A revision of the moths of the subfamily Prodoxinae (Lepidoptera: Incurvariidae). U. S. Nat. Hist. Mus. Bull. 255:1 -1 70. Engllmann, G. 1871. Yucca and Hesperaluc. In: S.Watson's Botany of the Fortieth Parallel. Report of the United suites Geological Explanation of the I ortieth Parallel. V. Suppl., 496-497.Washington. En< ,ii Marin, U 18/ FNotOAon thoqenus Yucca. lians.Sl.l ouis Acad. Sci. 3:1 / 54. Engllmann, G.I 875. Notes on the genus Yucca. No. 2.1rans. St. Louis Acad. Sci. 3:2 10-21 4. > EpiiNG,C.and A.LHairii in \ i >l u I ubsp n n I nllonia 9:1 71-1 72. ' GtNiRY,H.S. 19/2 Tin -i . 'in L n hi r hi 4 mdbook No.399.U.S.D.A. .Washing- ton, DC. ' a ' Grlenhousl, J.A., i > JL , " and an 2001 t o >o ; , and Yucca Whipple's (Aqavat eae). Madrono (in press). Grii nit r,W., I., B.arrh.F.R., M< Nun, Bmr[>; I •; y I.M., Doe \,V., F o-e ., I.S., Nicolson, D.H.,Silva, hi PG,Sko«,, J E,Triii i i, i 1 i , NI,andH inDLad i International code of i t botanical nomenclatui I )Liis I I mil ode) ted ih ixl . nth International Botanical C ll onqiess St.l ouis, Mosoui i, July Auqust A 'A Reqnum Veg. 138:1-474. Hanson, M. 1993. Dispersed unidirectional introqression from Yucca schidigera into Y. A a i ata iAqavai eae). >. Ph. I Div.ei la!ion.( latemont Uiadualo G Iioelq alilomia. . ' > > . I 1- H iii t~.2000.Het Jones, M.E. 1 929. Notes and new species of United States plants. Contr. W. Bot. 1 5:46-75. Matuda, E.and I. Pina-Lujan. 1 980. Las plantas Mexicanas del genera Yucca. Serie Fernando de Alva Ixtlilxochitl. Coleccion Miscelanea Estado de Mexico. McKeivey,S. 1947. Yuccas of the southwestern United Stairs, Pari 7.1 he Arnold Arboretum of Harvard University, Jamaica Plain, MA. McKinniy, K. and J.Hk wm;. 1993. Yucca. ln:The Jep'.on manual: higher plants of California (J.C. Hickman, ed.). Univ. California Press, Berkeley. Munz, PA, 1968. A flora of California with supplement. Univ. California Press. Berkeley. Pellmyr.O. 1999.Systematic revision of the yucca moths in the Tegeticulayuccasella com- plex (Lepidoptera: Prodoxidae) north of Mexico. Syst. Entomology 24:243-271 Yucca whipplei i 1 of moths and Powfi , J. and R. Mackie. 966. Biological interrelationships r i - m i ir| I (Lepidoptera:Ge!echiidae,Blastohi ih I i I M Ut I ubl Entomology 42. Univ. Calif. Press, Berkeley, C A. Riley, C. 1 892. The yucca moths and yucca pollination. Annual Rep. Missouri Bot. Gard. Segraves, K.and O. Pellmyr. 2001. Phylogeography of the yucca moth Tegeticula maculata: the role of historical biogeography in reconciling high genetic structure with limited speciation. Molec. Ecol. 1 0:1 247-1 253. Starr, G. 1 997. A revision of the genus Hesperaloe (Agavaceae). Madrono 44:293-294. Torrey, J. 1 859 [1 858]. Yucca whipplei Jon., ImW.H. Emory, Report on the United States and Mexican boundary survey. 2:222. Torrey, J. 1861. In: J.C. Ives, Report upon the Colorado River. Catalogue of the plants col- lected upon the expedition.4:[1]-30. Trelease, W. 1 893. Further studies of Yucca and their pollination. Annual Rep. Missouri Bot.