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THE GENUS PACKERA (ASTERACEAE; SENECIONEAE) COLORADO, IN U.S.A. Debra K.Trock^ Fon\A ABSTRACT SSSE mtlypubUshed floras for the state have 'ackera,Senccw.ndUgul treated enca some among Project, the author cliscovered confusion INTRODUCTION What Distinguishes a Packera from a Seneciol m now Traditionally, species included Packera were relegated to the genus Senccio, a large genus of over 3,000 species. In the early 1800s DeCandolle (1838) pro- vided a worldwide treatment of Senecio. He recognized 16 informal groups, based largely on geographic distribution. Greenman (1915, 1916, 1917, 1918) and Rydberg had varying and numbers (1900) definitions of informal "species groups." Through the 1960s into the 1980s Barkley (1962, 1968a, 1968b, 1978, 1980) pub- lished several papers on three of these informal groups, the Aurei, the Lohati and which the Tomentosi, he collectively referred to as the "Aureoid Senecios." Within most chromosome number Senecio of the taxa have a base of s.l., x=10 or derivatives thereof. However, Love and Love (1976) pointed out that there was group anomalous whose chromosomal number was a of species base either x=22 or x=23 and had a suite of unique morphological characters. Further- New more those taxa corresponded to three World groups informally recognized by Barkley: the Aurei, the Lohati, and the Tomentosi. They proposed that new these species be placed in a genus, Packera, based primarily on gross mor- phology and chromosome number and The recognition Packcni was not immediately accepted not of still is some However, support recognizing Packera has recognized by workers. for and grown over the past 25 years. Molecular, palynological, cytological data, while doing to help clarify relationships between species in this group, little have support recognizing the genus Packera. These types of data are lent for all how acquired by laboratory work, but does a botanist in the field decide he/ if comparison she looking at a Packera or a Senecio'? Table 1 provides a of char- IS herbarium Often combina- acters that are useful for field or identifications. a make tion of these features will be needed to a determination. AND METHODS MATERIALS While preparing a treatment of the genus Packera for the Flora oj North many and America borrowed specimens from regional herbaria, vis- project, I and good un- ited several others to obtain both accurate distribution records, a derstanding of the morphological variation that characteristic of these spe- is made have also four collecting trips through the central part of Colorado, cies. I where the diversity of Packera the highest. During the course of that work is it among became apparent that there was confusion local botanists concerning which characters provide accurate identification, and about which species for belong in the genus Packera, and which are treated as Senecio still s.l. have examined over 1100 Colorado specimens from the following herbaria: 1 Adams State College (ALAM); Botanical Research Institute of Texas (BRIT); Museum Brigham Young University (BRY); Canadian of Nature (CAN); Colo- rado College (COCO); Colorado State University (CS); Kansas State University (KSC): Miami University (MU); Missouri Botanical Garden (MO); Montana State New (MONT); Garden North Dakota Uni- University York Botanical (NY); State (NDA); Northeast Louisiana University (NLU); Oregon State University versity Rancho Ana Garden Rocky Mountain Herbarium (OSC); Santa Botanic (RSA); Museum Columbia (RM); University of Alaska (ALA); University of British (UBC); University of California (UC); University of Colorado (COLO); Univer- New sity of Kansas (KANU); University of Mexico (UNM); University of South- ern Colorado (PUSC); University of Washington (WTU); and Vanderbilt Uni- (VDB). versity common synonyms, The goal of this paper to provide descriptions, keys, is and a discussion of the most useful morphological characters to assist bota- maps nists in their efforts to accurately identify species in this genus. Dot pro- viding distribution information for each species are presented in Figures 2 1, and 3. Generic characters of Colorado Packera species and most Three All taxa of Packera are exclusively herbaceous, are perennials. and P neomexicana can of the Colorado species, multilohata, plattensis, also P. P. Barkley within 5enec/o NOT leaves clasping Caudices taprooted or may be biennials, and neomexicana occasionally be a winter annual. Stems of P. all Packeras consistently grow from either a single or a cluster of basal rosettes. A The woody perennating structure a caudex or a shortened rhizome. is caudex the persistent base of an herbaceous stem that normally arises from a is taproot. In some species the caudex short, thin, and weak, while in others is it can become elongated, branching, stout, and woody Species that inhabit steep meadows rocky slopes have creeping rhizomatous caudices. Taxa growing in wet or other mesic environments frequently have abundant fibrous which roots, may almost completely disguise the presence of the caudex. Stems normally from caudex However, because are single the or taproot. in many may more species the caudex or less branching, appear that there are is it several stems clustered together, but usually no more than four or Some five. may species have stems that display anthocyanic (reddish) pigments. P growing open sagebrush and growing on multilohata, in habitats, portcri, ta- P. both lus slopes exhibit this characteristic. amount There considerable variation in the of pubescence along the is stems. In Colorado, P cana, Pfendkri, and P werneriifolia are nearly always densely tomentose. Other species vary widely in the amount and persistence tomentum. Almost Packeras have some pubescence of all at least restricted to when the base of the stem and to the axils of the leaves young. Although the commonly presence or absence and location of pubescence used in keys and is when descriptions, should only be used in conjunction with other characters it identifying specimens. The shape and texture of basal leaves have long been of key taxonomic importance in the genus. The shape of the blade, base of the blade, and blade margins are the three most important characters. In general the basal leaves are 1 ^^^Wf r^f^^i^^^^ — 1 J =sss^ ^1 rW> nA?rP /* ns\ ;i^ _1^ ^,1 kf ^K iVr-cS^ / The records for each county are supported by at least oi paper la cited in this may caulinc leavcb can also be Ubclul, but there be '\ in species In all species of Paihcra, the basal leaves cauhnc vhile the leaves aic eithet gradually, progres- upwards on uppermost sively, or abruptly reduced the species, the si 1 and most cauline leaves are sessile are bract-like. The heads in the inflorescence are arranged in either subumbellate or corymbiform Two and always cymes. species (P.porteri wcrneriijolia) nearly P. have only one large terminal head or at most two or three smaller heads. Most species of Packera have 8 or 10 or 13 ray florets per head. However, P. A P few including paupercula, dehili^, typically rayless. others, porteri, is P. P. and most pseudaurea, werneriifolia are occasionally rayless. In species the P. R dimorphophylla dimorphophyUa and florets are a bright yellow. var. crocata P. frequently have florets that are deep orange-yellow to almost brick-red. P. may have deep orange-yellow streptanthifolia rays that are a as well. Another character that frequently used in descriptions size and pu- is is bescence of the cypselae. While there is variation in size, P. ca na has noticeably Many large fruits and dimorphophyUa has noticeably small ones. species have P. glabrous fruits, but a few have tiny hairs along the ribs of the cypselae. COLORADO KEY TO THE PACKERAS OF combination e of cl meadows open Plants of i may Plants glabrous, be tomentose v Plants with a single large head; involucres deeply anthocyanic, basal leaves . reniform to subrenifornn, cauiine leaves reduced to bracts, plants of alpine Plants with few to several heads, involucres and leaves without the above . combination of characters. 8. Basal leaf blades narrowly to broadly lanceolate,oblanceolate or narrowly elliptic. P.tridenticulata , Low(er cauiine leaves various; calyculate bracts either few and incon- '. moun- spicijous or large and conspicuou5;cyps elae glabrous; plants of meadow wet tain or habitats. 10. nvolucres dark green, often with arithocyanic tips; heads with nu 1 .erous large conspicuous calyculat e bracts P.streptanthifolia var streptanthifolia nvolucres green, not anthocyanic; calyculate 10. light tips dist:inctly 1 Leaf blades broadly lanceolate .ovate;baseofleafbladestrun- tc 11. cate to subcordate or occasiona obtuse; lower cauiine leaves lly sublyrate to subentire; middle id upper cauiine leaves sessile ai and frequently clasping P.pseudaureavarflavula leaf blades broadly elliptic, obovate or oblanceolate to ovate or I _eaf margins lobed or pinnatifid; plants of sandy sagebrush habitats multilobata P. _eaf margins variously dentate to crenate or shallowly lobed but never Dinnatifid; plants of alpine to subalpine habitats Lower and middle cauiine leaves sessile conspicuuuslv cla5f:>ing 13. Rdimorphophylla dimorphophylla and auriculate t often deep orange yellow or brick red,calycula Leaf blades thick and turgid, margins variously . AND COMMENTS ON DESCRIPTIONS IDENTIFICATION SPECIHS & WA. Weber Packera cana (Hook.) A. Love, Phytologia. 49:46. 1981. Seneaocanus Hook, Perennials. Caudices stout, branching rhizomatous, suberect. Stems single from a rosette, or clustered rosettes, densely lanate-pubescent or canescent. Basal leaves petiolate, blades ovate or elliptic to lanceolate, 2.5-5+ x 1-3 cm, bases margins undulate weakly tapering, entire or irregularly to dentate, persistently canescent on lower canescent subglabrescent on upper surface, to surface. Cauline leaves petiolate to sessile and weakly clasping, progressively reduced margins weakly Heads distally, elliptic to lanceolate, entire to dentate. radiate, 8-15+ corymbiform in arrays. Peduncles bracteolate, densely lanate to loccose f some tomentose, subglabrescent in populations. Calyculi present, inconspicu- mm, 5-8+ Ray ous, tomentose. Phyllaries 13 or green, densely tomentose. flo- 21, mm. rets 8-10 or laminae 8-10+ Disc florets 35-50+; corolla tubes 2.5-3.5 13, mm mm mm, mm. limbs 3.5-4.5 Cypselae 2.5-3.5+ long, glabrous, pappi 4.5-7 2n=46. long. Packera cana found on open high and sagebrush plains in associations. is also collected from dry rocky slopes and from crevices on both granitic is It and limestone outcrops. flowers from late June into August, depending on It and and abundant Although latitude elevation very in Colorado. this species is found on grasslands Wyoming, Montana, North Dakota, South Dakota, and in is Nebraska, rarely found on the high plains of the eastern part of Colorado. is it which Probably the only other species in Colorado with can be confused it Two werneriijolia. features contribute to this potential confusion: At very is P. 1) may high elevations P cana be very short 10 cm); P werneriijolia can be (< 2) P nearly as pubescent as cana. There two two P cana are features distinguishing these species: nearly 1) always has more than 3 heads in the inflorescence. At high elevations the inflorescence often very compact, and the heads are small. Packera werneriijolia, is on the other hand, normally has only or two large heads. can occasionally 1 It have 3-5 heads, in which case they are smaller than normal. 2) P cana always has some cauline leaves even they are very reduced and mostly on the lower if portion of the stem, while P werneriijolia nearly always scapose, or in some is may very robust specimens, have a few bract-hke leaves on the stem. & Weber Packera crocata (Rydb.) Love, Phytologia. 49:46. 1981. SeneciocmcatusRydh. Perennials. Caudices long, stout, horizontal to ascending. Stems 2-6+ dm, single 2-3 or rarely clustered, glabrous. Basal leaves thin petiolate, blades narrowly lanceolate or ovate to oblong ovate, 2-6+ x 1-4+ cm, bases abruptly contracted to tapering, margins subentire to crenate^dentate. Cauline leaves petiolate to and weakly reduced sessile clasping, progressively distally, lanceolate to ob- margins Heads 7-15+ open corymbiform long, sublyrate or lobed. radiate, in arrays. Peduncles absent or small and inconspicuous, glabrous. Calyculi absent mm, or few and small. Phyllaries 13 or light green or with reddish 4-8 21, tips, mm, Ray 6-8+ glabrous. florets 8 or corolla laminae deep yellow to orange- 13, mm, mm. red. Disc florets 60-80+; corolla tubes 4.5-5.5 limbs 2.5-3.5 Cypselae mm mm 1-1.5 long, glabrous, pappi 3-5 long. 2n=46. meadows This species grows in wet often associated with grasses, sedges and willows, along and rocky outcrops middle subalpine trails in at to eleva- may tions and flowers from early July to mid- August. The only species that it be confused with dimorphophylla dimorphophylla. Three var. features dis- is P. tinguish these two species: P.crocata has an open inflorescence, while that of 1) dimorphophylla dimorphophylla compact and congested. var. 2) is P. P. dimorphophylla has dramatically and conspicuously large, auriculate, clasp- may ing middle and upper cauline leaves. While P crocata have larger than normal cauline leaves, they are at most weakly clasping. 3) While both species generally grow in wet places, P crocata grows at elevations of ca. 8,000 - 10,000 feet and and while P dimorphophylla dimorphophylla is fairly tall thin, var. is almost never found below 10,000 and normally more compact feet a plant. is frequently noted in the literature that P crocata has orange to reddish is It ray However, P crocata sometimes produces deep yellow ray and florets. florets, may P dimorphophylla var dimorphophylla produce orangish ray florets. & Weber Packera debilis (Nutt.) W.A. A. Love, Phytologia. 49:46. 1981. Senecw 2-4 Perennials. Caudices short, weakly branching. Stems 20-50+, single or clustered, bases lightly floccose-tomentose or glabrous, leaf axils tomentose. Basal cm and 2-4+ x leaves petiolate turgid, blades elliptic to ovate or subreniform, 1.5- 3+ cm, bases cuneate to subcordate, margins subentire or crenate to crenate-dentate. Cauline leaves petiolate to sessile, progressively reduced distally, blades pin- nate-lobed, sinuses deep and rounded, lobes with entire to subentire margins. Heads 6-20+ open compact corymbiform Peduncles eradiate, in or arrays. present, short and conspicuous or absent, glabrous or lightly pubescent. Calyculi present, mm, few and inconspicuous. Phyllaries 13 or green with reddish 6-8+ tips, 21, mm, Ray 3-4 2- glabrous. florets absent. Disc florets 45-65+, corolla tubes limbs mm mm mm. 3 Cypselae 1-2 long, glabrous, pappi 4.5-5.5 long. 2n=46. This a distinctive plant of central and northern Colorado. collected is It is frequently in Park County and less frequently in northern counties at mid to meadows subalpine elevations in open with alkaline Packera dehilis soils. is sometimes identified as P paucijlora, which also a rayless plant with reddish is and does not occur in Colorado) a suite of characteristics that distinguish (it it more from Packera dehilis generally has than 6 heads in the inflo- dehilis. 1) P. rescence while pauciflora normally has 6 or fewer large heads. 2) Packera P. has very short bracteoles on the peduncles, while pauciflora has very dehilis P. large conspicuous ones. 3) Packera dehilis, has very few greenish, inconspicuous calyculate bracts. P pauciflora, on the other hand, has long calyculate bracts The that are normally quite reddish in color or at least have red tips. 4) involu- may cral bracts of dehilis display reddish coloration on the upper one-half to P. normally deeply one-third of the but the involucres of pauciflora are tips, P. anthocyanic throughout. Probably the most easily distmguished character- 5) The concerns the lobnig of the mid-cauline leaves. terminal lobe of the istic leaves on dehilis narrow and pointed, and the sinuses of the individual lobes is P. deep and rounded. are known Although P dehilis has been at least from Park, Larimer, and Jack- many and son counties for years, is very infrequently collected is confined to it meadow may worthy and an alkaline habitats. indeed be of special note, ef- It made document should be existing populations. fort to & Weber dimorphophylla W.A. A. Love, r. Stems 1- Perennials. Caudices short, stout, fibrous-rooted, horizontal to erect. 3+ dm, single or rarely 2-3 clustered, simple or branched, glabrous. Leaves: basal leaves petiolate, thick and turgid, blades varying from ovate to subreniform or broad-winged margins occasionally oblanceolate, bases tapering to a petiole, lower and mid-cauhne conspicuously clasping entire to crenate; leaves sessile, and than obovate auriculate, blades as large or larger basal leaves, oblanceolate, or lyrate, margins subentire to bluntly and irregularly dissected; upper cauline and leaves usually reduced to sessile bracts, occasionally large conspicuous. Heads congested corymbiform subumbellate radiate, 1-6-h in or arrays. Pe- duncles inconspicuously bracteolate or bracteoles absent, glabrous. Calyculi conspicuous, bases swollen. Phyllaries 13 or occasionally fewer, green with 21, mm, 5-7+ Ray anthocyanic apices, glabrous. florets 8 or deep yellow to or- 13, mm. mm, ange, corolla laminae 5-8+ Disc florets 45-60+, corolla tubes 2-3 limbs mm mm mm. 3-4 2.5-3.5 Cypselae 0.75-1.5 long, glabrous, pappi long. 2n = 46. This species quite distinctive and only rarely confused with one other is is A P entity in Colorado, crocata. discussion of the characters used to separate two found with P found the species the description of crocata. at eleva- is It is damp meadows and on tions generally over 10,000 feet in or in seeps crevices from mid-August. hillsides. flowers early July to It & Weber Packera fendleri (A. Gray) W.A. A. Love, Phytologia, 49:46. 1981. Scneao