Nee? ee . 2 _ PHYTOLOGIA “Ao international journal to expedite plant systematic, phytogeographical i and ecological PUCHEETION | mH Vol: 77 ee . September 1994 eae ote NOs 3 a Be CONTENTS yA ,NESOM, ce a, ‘Abview a the taxonomy of Aster sensu lato (Asteraceae: ah - Astereae), emphasizing the New World : SPECIES. <0. - sess sess evs LAL 7. NESOM, G. L., Hybnidization i in the tribe Astereae. ..............2.... 298 | Phytologie Memoirs available. eee SES diy aioe aes rg vies, 308 | |RRARY rep 44 : NEW YORK, ae BOTANICAL GA sean | ie ce os Published by Michael J.Warnock | “185 Westridge Drive Huntsville, Texas 77340 U.S.A. sued beeen ohne is ne on acid free conan ba ee eS eit “ 7 PHYTOLOGIA 4} PFS An Vaiterdaslional journal to expedite plant systematic, phytogeographical and ecological publication Wats FF | September 1994 , No. 3 CONTENTS | NESOM, G. is Review of the taxonomy of Aster sensu lato (Asteraceae: Kitordaey, emphasizing the New World SPECIES. 96.6 eee e eee eee ee ves 141 / NESOM, G.L., Hybridization in the tribe Astereae. ...........00.0000- 298 Phytologia Memoirs available. POPES ES BOA Si Rey mee see et eee 308 ) (RRARY new YORK BOTANICAL GARDEN Published by Michael J. Warnock - 485 Westridge Drive Huntsville, Texas 77340 U.S.A. i _PHYTOLOGIA is printed on acid free paper. 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REVIEW OF THE TAXONOMY OF ASTER SENSU LATO (ASTERACEAE: ASTEREAE), EMPHASIZING THE NEW WORLD SPECIES Guy L. Nesom Department of Botany, University of Texas, Austin, Texas 78713 U.S.A. ABSTRACT The genus Aster (as typified by A. amellus L.) and its closest rel- atives comprise the subtribe Asterinae s. str. These ca. 306 species in thirteen genera are primarily restricted to the Old World; Aster is the largest of these (with ca. 180 species) and is restricted to the Northern Hemisphere of the Old World, except for the seventeen species of Aster sect. Calimeridei (the A. harveyanus Kuntze group), which occurs in southeastern Africa, and A. alpinus L., which occurs in Asia and North America. The status of problematic, potentially generic-level Asian groups presently maintained within Aster s. str. is discussed. Boltonia is the only American genus hypothesized to be in the Asterinae. The New World species previously classified primarily within Aster are here ap- portioned among eleven previously described genera and two new ones, including the following (with number of species indicated): Almutaster (1), Ampelaster gen. nov. (1), Chloracantha (1), Canadanthus gen. nov. (1), Doellingeria (11 - three from North America, eight from Asia), Eucephalus (11), Eurybia (28), Ionactis (5), Oclemena (3), Oreostemma (3), Pstlactis (6), Sericocarpus (5), and Symphyotrichum, including Vir- gulus (97). The status of Tonestus (eight species) within the Asterinae is considered, but it probably is best placed within the Solidagininae. A taxonomic account is provided for infrageneric categories and all 181 species of these fourteen American genera (including Tonestus), with new combinations necessary to establish a complete nomenclature; mor- phological summaries are provided for all. The validity and typification of the name Eurybia (Cass.) S.F. Gray is discussed in detail. Asian Asterinae are generally characterized by obovate, flattened, 2-nerved achenes commonly with glandular faces and are hypothesized to com- prise a monophyletic group. American species (the Symphyotrichinae) are generally characterized by their cylindric to fusiform, terete, multi- nerved, and eglandular achenes, but transitions to flattened and few- nerved achenes apparently have occurred in parallel with Asian taxa. 141 142 PHYTOLOGIA volume 77(3):141-297 September 1994 Similarities between the two groups and the apparent basal position of the American taxa suggest that all should be included within a single subtribe, the Asterinae. Phylogenetic hypotheses are presented for re- lationships among the American genera. A discussion of chromosome evolution within the tribe Astereae is provided, with reference to the definition of Asterinaean genera. KEY WORDS: Aster, Asterinae, Astereae, Asteraceae, Old World, New World INTRODUCTION Most systematists dealing with the genus Aster have recognized it as tax- onomically difficult with regard to the delimitation of species as well as the recognition of natural groupings of species. There have been numerous pub- lished studies in the last fifteen years at both levels of the taxonomy of Aster. Two such studies, concentrating on the North American taxa, have provided independent and divergent overviews of the taxonomic structure of the genus (Jones 1980a; Semple & Brouillet 1980a). These botanists, and others, have also provided a great deal of new and critical data on chromosome numbers (see summary by Semple 1992) and morphology within the Aster alliance, clar- ifying the boundaries of species and species groups. The present study reviews recent developments in the taxonomy of Asters. lat. aod provides a signifi- cantly different. perspective on the taxonomy of the group, based primarily on a morphological survey. The taxonomic status of New World and Old World groups is considered; alternative treatments are proposed for a number of the New World species and suggestions are made for alternative treatments of Old World species and species groups. The comments of Cronquist (1947, p. 147-148) can serve as a starting point in the present review: “Until the publication of the first part of the second volume of the Genera Plantarum [Bentham and Hooker 1873], it was cus- tomary at least in America to regard the various Aster-segregates as valid genera. Asa Gray rather reluctantly followed Bentham’s sweeping reduction of most of the segregates, and further pointed out that if these were to be reduced, Brachyactis would have to follow.” “While the extended definition of Aster has certainly not been uniformly accepted, it has been followed by the majority of Amer- ican taxonomists since Gray’s adoption of it, more especially so since the swing away from the splitting vogue of the first quarter Nesom: Review of Aster taxonomy 143 of this century. The Benthamian definition, with Gray’s addition of Brachyactis, was also adopted by Hoffmann [1890] in his treatment of Compositae for the Naturlichen Pflanzenfamilten.” “Although I do not wish to become involved at this time in a discussion of the propriety of the extended definition of Aster, I must support it, with some misgivings, at least until a thorough study of the old-world as well as the American species provides a reasonable basis on which all species can be referred either to Aster proper or to a morphologically definable segregate.” The direction of the present review is based on two broad observations, derived in part from a study of the entire tribe Astereae (Nesom 1994e). First, typical Aster and its closest relatives (the subtribe Asterinae s. str., comprising fourteen genera) appear to be restricted to the Old World (except for the New World Boltonia). And second, more than half of the species that have been included within New World Aster appear to constitute a diverse but coherent group (the genus Symphyotrichum, as interpreted here), and a smaller number of North American species groups represent separate phylads. Most of the latter have previously been segregated as independent genera, their morphological and phyletic distinctions equivalent to those among other genera in the rest of the tribe. In an earlier study (Nesom 1993c) I placed Sericocarpus as a basal member of the subtribe Solidagininae. In contrast, it is placed here among the North American groups of asters, with the acknowledgment that Cronquist (1947b) was correct in adding this group of species to those that constitute Aster in the broadest sense and that Semple & Brouillet (1980a) and Jones & Young (1983) correctly placed it near most of its closest relatives in their classifica- tion. Sericocarpus is hypothesized here to be most closely related to the North American genus Eurybia, although its plesiomorphic similarities to the Sol- idagininae may reflect a closeness of common ancestry. Similarly, Jonactis was recently hypothesized to be the most primitive member of the Chrysopsidinae (Nesom & Leary 1992), but that subtribe is a well-defined group without Jon- actts, which is hypothesized here to be relatively isolated but perhaps most closely related to the genus Eucephalus among North American asters. In the present view, relatively few species of only one other genus, Psilac- tis, need to be added to the other New World species before the entire assem- blage could be considered a single, heterogeneous genus. Species of Psilactis have been included in Aster, most recently by McVaugh (1984), and Morgan’s molecular data (1990, 1993) suggest that species of Psilactis are closely related to others treated here within Symphyotrichum. One species of the genus Tonestus has been included in Aster (T. kingii (D.C. Eaton] Nesom, see Nesom 1991b). The genus was included among the North American asters in my subtribal classification (Nesom 1994e), and it is 144 PHYTOLOGIA volume 77(3):141-297 September 1994 tentatively maintained there in the present review. It is anomalous there, how- ever, in its mix of discoid and yellow- and white-rayed species and the papillate collecting appendages of the disc flowers. The other species of Tonestus were mostly treated previously within Haplopappus, which has now been completely dismantled in North America (Nesom & Morgan 1990) and distributed among a number of phylogenetically disparate genera. The molecular data of Morgan (1990) suggest that Tonestus is closer to the Solidagininae. In a recent overview and taxonomic summary of the tribe Astereae (Ne- som 1994e), I suggested that North American Aster should be divided into a number of genera. That course is discussed in detail below and the neces- sary taxonomy formalized, with two significant updates. I have since realized that the earliest, legitimate, available generic name for the species I divided between Heleastrum and Herrickia is Eurybia (Cass.) S.F. Gray (see detailed discussion below). And with additional perspective, I find that the distinction between the subtribes Asterinae and Symphyotrichinae cannot be maintained, and the latter (newly proposed by me) becomes a synonym of the former. Maintenance of a “conservative” treatment, or a “traditional” treatment, of Aster has sometimes been stressed as a valuable objective or at least im- plied to be such. Use of these terms, however, to describe the most current classifications of Aster is only partly appropriate, as nomenclature is already in place for long-recognized segregates. Further, the current view of Aster was engendered by a fundamental, abrupt (vs. conservative) broadening wrought primarily by Bentham and Gray and extended nearly ‘o its limit by Cron- quist. Some of such North American segregates have been included in Aster for a shorter time than they were treated as independent genera, and a truly traditional approach, with no other considerations, would be to treat them separately. The current, broad concept of Aster may be conservative in the sense of inclusiveness, but significant elements of what is conserved have been accreted in recent years. Further, until now the taxonomy of the genus has not been critically examined within the context of other genera of Astereae or, for the most part, even among a broad representatiou of species and gen- era from outside of North America that might be closely related to Aster s. lat. The treatment presented here could be considered conservative in that it maintains, in large part, a large and morphologically diverse group of species within a single genus (Symphyotrichum). I. Review of recent Aster classifications Both of the recent taxonomic overviews of Aster (Jones 1980a; Semple & Brouillet 1980a) included within the genus all of its previously proposed North American generic segregates, as well as several Old World ones, both studies beginning with the assumption that such a broadly conceived Aster is indeed’ Nesom: Review of Aster taxonomy 145 a monophyletic group. Both studies sharpened the definitions of subgroups within North American Aster, but neither provided a circumscription of the genus that would enable the exclusion of any group. In fact, it is difficult to find any more specific definition of Aster (as currently treated) than as erect, leafy-stemmed, mostly rhizomatous herbs with white or blue rays, involucral bracts herbaceous or with an indurate base and herbaceous tip, style branches of disc flowers with lanceolate collecting appendages, and a pappus of capillary bristles. Even among the features in this most general of characterizations, there are significant exceptions and qualifications to every character except the basic nature of the pappus. The taxonomic system by Jones is essentially phenetic, recognizing many formally designated subgenera (further divided into sections and subsections) grouped informally by similarity in chromosome number. Semple & Brouillet weighted the significance of the morphology of the satellite (NOR) chromo- somes and the morphology of the phyllaries, and they also were guided by their stated assumption that groups of Astereae with base chromosome numbers of z=5 are for the most part cladistically far-removed from z=9 and z=8 taxa. The taxonomic categories of Semple & Brouillet were informally designated. The two classifications are similar in some essential features: the z=9 groups in both include typical Aster as well as other diverse groups; both recognized the z=8 species as constituting a monophyletic group; both recognized the “grass-leaved species” (subg. Heleastrum) as a natural subgroup but differed in regard to its placement within the genus (additional comments below); and both recognized the “virguloid” z=5 species as monophyletic. In contrast, Jones included both z=5 and z=9 species in her subg. Ozytripolium, while Semple & Brouillet suggested that the z=5 members of Ozytripohum should be separated from Aster as a distinct genus. Semple & Brouillet (1980a) for- mally elevated the virguloid species to generic status (as the genus Lasallea E. Greene, re- formalized as Virgulus Rafin. by Reveal & King 1981), observing that the species of their new genus “do not show any more relationship to the species of Aster than to other genera of the tribe” (additional discussion below). The phylogenetic analysis by Jones & Young (1983), which was the first to provide such a perspective for Aster, hypothesized that groups traditionally recognized as subgenera and sections are cladistically intermixed, given the ini- tial assumptions and data of the study. Their analysis alternatively positioned Heleastrum as a subgroup within Virgulus or as its sister group; Ozytripolium was positioned either as the sister group to the z=8 species (including Brachy- actis = subg. Conyzopsts) or close to it, the combined element in both cases nested within Aster proper. This phylogenetic hypothesis was then used as part of an argument for retaining a broadly conceived Aster, including the species of Virgulus, Ozytripolium, and Brachyactis. The analysis by Jones & Young (1983), however, was inherently unable 146 PHY TOL@OGIiA volume 77(3):141-297 September 1994 to demonstrate that Aster, as they viewed it, was a natural group. They chose Erigeron as the single outgroup to establish the evolutionary polarity of character state changes within Aster. The assumption that Erigeron is the closest relative of Aster apparently was based in large part on statements by Cronquist (e.g., 1947), who seems to have developed this view based primarily on similarities in habit, although he never provided details of justification. The species of Erigeron sect. Fruticosi G. Don, which were utilized by Jones & Young (1983) as the sister group of Aster, produce rhizomes and tall, leafy stems and are superficially similar to some species of Aster, but in details of vestiture, capitula, flowers, and fruits, they are similar to the rest of Erigeron but not to any group of Asters. lat. A species interpreted as an intergeneric hybrid between Aster and Erigeron (Asterigeron watsonii [A. Gray] Rydb. = Aster watsonii A. Gray) clearly has its closest relatives within Erigeron (Nesom 1989a) and is placed there as E. watsoni (A. Gray) Crong. Some monocephalous species of Aster (e.g., A. alpinus L.) resemble some species of Erigeron, and vice versa (e.g., the Asian E. thunbergiz A. Gray has been treated as Aster), but Erigeron and Aster can be separated by reference to a set of various features (e.g., Cronquist 1947; Tamamschyan 1959; Grierson 1964), the resemblance between the two genera a result of convergent evolution. The closest relatives of Erigeron are hypothesized to be the primarily South American Conyza and four other genera entirely restricted to South America, these six genera constituting the subtribe Conyzinae (Nesom 1994e). In the review and appraisal of their own analysis, Jones & Young (1983, p. 80) noted that the delimitation of major groups (“principal clusters”) could be made with confidence but that “considerable instabili:y was evident in the lower branches, and we have little confidence in the putative relationships among the clusters, as defined by the lowermost nodes.” In their summary diagram of the phylogeny of Aster (Figure 5, “Putative relationships within Aster”), seven major groups arise independently from a hypothetical com- mon ancestor, these groups corresponding to those delimited in their “branch- swapping” cladogram (Figure 4), which were derived froin the input of a phe- netic analysis rather than their “Wagner” analysis (Figure 2). Aster s. str. was placed in the summary diagram in a group with Sericocarpus and several groups of American Aster, but Asters. str. was positioned in their “Wagner” cladogram as the sister group to a much larger clade including their Symphy- otrichum and Tripolium s.l. They did not indicate why they chose the results of one analysis rather than the other. As Jones & Young noted (1983, p. 83), a better answer to the question of whether or not Aster is monophyletic “probably can be found only in a com- parison of potential segregate genera with other genera in the Astereae.” Such necessity for a broader approach in the assessment of evolutionary affinities has been emphasized by recent DNA studies including a broad range of genera of North American Astereae by Suh (1989) and Morgan (1990), who have shown Nesom: Review of Aster taxonomy 147 that the species of Aster in their samples form a group more closely related to genera of Astereae other than Erigeron (see Nesom et al. 1990 for a summary of broadly defined phyletic lines in North American Astereae), particularly those of the subtribes Machaerantherinae (Morgan & Simpson 1992), Chrysopsidinae (Nesom 1991b), and Solidagininae (Nesom 1991c, 1991d, 1993c). Ten North American species sampled by Morgan (1990) form a monophyletic group in part corresponding to what has traditionally been recognized as Aster: A. ericoides L. (subg. Virgulus) is closely related to A. drummondii Lindl. and A. carnerosanus S. Wats. (both of subg. Symphyotrichum, as treated here) and these three in turn are phyletically close to a group that includes the Ozytripolium group of Aster (sensu Sundberg 1986), Aster pauctflorus Nutt., and the species of Pszlactis (sensu Morgan 1993). Although these studies are significant, species of Asters. lat. occupying critical positions (mostly those phylogenetically more basal) in hypotheses formulated in the present paper have not yet been included in molecular analyses, and the taxonomic place- ment of Morgan’s species is equivocal in a larger context. My ideas regarding the phylogeny of North American asters and corre- sponding taxonomic arrangement may not be exactly aligned with What Na- ture Has Wrought but they are based on detailed observation and broadly based consideration. The species groupings of the present treatment are simi- lar in many ways to those of earlier studies, but the taxonomic system here is a notable departure from other relatively recent summaries (t.e., Jones; Jones & Young; Semple & Brouillet). Molecular studies (chloroplast DNA) now un- derway in the laboratory of Dr. John Semple will soon provide an independent evaluation of these morphologically based treatments. II. Recent additions to New World Aster In the last twelve years, many nomenclatural changes have been proposed within Aster, primarily among North American taxa, particularly with re- gard to delimitation and redefinition of species and varieties. The major- ity of such studies have been by A.G. Jones, J.C. Semple, K.L. Chambers, or associated research groups. Many of these are cited in other contexts in the present paper; other representative studies are cited here (Semple 1984; Semple & Chmielewski 1987; Lamboy et al. 1991). Several new species have been described (Sundberg & Jones 1986; Lamboy 1988; Campbell & Medley 1989; Nesom 1989b; Cronquist 1994). Chrysopsis brewert A. Gray, a rayless species from California and adjacent Nevada, was recently transferred by Sem- ple (1988) into Aster subg. Eucephalus, a group that clearly includes its closest relatives. Most of the new taxa at or near specific rank have had little direct bearing on problems regarding generic definitions or subgeneric classification. 148 PHYTOLOGIA volume 77(3):141-297 September 1994 III. Recent segregates from New World Aster Since the 1980 classificatory papers and the phylogenetic study in 1983, a number of species or species groups have been transferred, segregated, or resegregated from Aster to other genera: (1) Aster lepidopodus B. Rob. & Fern. to Erigeron L. (Nesom 1981); (2) Aster riparius Kunth to Machaeranthera sect. Arida Hartman (Stucky 1978; Jones 1983a); (3) two new genera recently segregated from Aster (Almutaster and We- beraster) and several nomenclatural transfers made from Aster to the established genus Symphyotrichum Nees (Love & Love 1982); no com- ments past the nomenclatural necessities were provided in justification of their proposed taxonomy, but these taxa are discussed in detail in the present paper; (4) Aster intricatus (A. Gray) S.F. Blake to Machaeranthera sect. Arida Hart- man (Nesom 1989d); (5) Aster blepharophyllus A. Gray to Machaeranthera sect. Artda Hartman (Nesom, Vorobik, & Hartman 1990); (6) Aster spinosus Benth. to Chloracantha Nesom et al. (Nesom et al. 1991a; Sundberg 1991), completing the dismantlement o! Aster (subg. Ozytrv- polium| sect. Spinosi (Alex.) A.G. Jones (the only other species included was Aster intricatus - see number 4 above); (7) Aster kingit D.C. Eaton to Tonestus A. Nelson (Nesom 1991b); (8) the three species of Aster subg. Janthe (Torr. & Gray) A. Gray to the genus Jonactis E. Greene (Nesom & Leary 1992 for a summary and new species; Nesom 1992b for the incorporation of a fifth species); (9) the three species of Aster subg. Oreostemma (E. Greene) Peck to the genus Oreostemma E. Greene (Nesom 1993a; also see Nesom 1992a); (10) the five species of Aster subg. Sericocarpus (Nees) A.G. Jones to the genus Sericocarpus Nees (Nesom 1993b); (11) Aster ptarmicoides (Nees) Torr. & Gray to Solidago L. (Boivin 1972; Brouillet & Semple 1981) but more recently placed in the genus Oligoneu- ron Small (Nesom 1993c); (12) five species of Aster from Madagascar segregated as the new genus Mada- gaster Nesom of subtribe Hinterhuberinae (Nesom 1993d); Nesom: Review of Aster taxonomy 149 (13) Aster grisebachii Britton from Cuba confirmed as a species of the “pini- folia group” of Hystertonica (Nesom 1993e), this group subsequently re- segregated as the genus Neja DC. (Nesom 1994d); (14) eleven species of Aster (subg. Doellingeria| sect. Triplopappus (Torr. & Gray) A.G. Jones consolidated from among American and Asian species and treated as the separate genus Doellingeria Nees (Nesom 1993f); (15) Aster warmingiit Baker and A. tuberosus Less. ex Baker segregated as the primarily Brazilian genus Apopyros Nesom (Nesom 1994a), which is a member of the Leptostelma D. Don group of the Conyzinae; (16) Aster camporum Gardner transferred to the South American genus /n- ulopsis O. Hoffm. (Nesom 1994b); (17) Aster subg. Conyzopsis (Torr. & Gray) A. Gray resegregated as the genus Brachyactis Ledeb. (Jones 1984, 1985), but a conflicting view has been held by Houle & Brouillet (1985) and the group is maintained in the present treatment as congeneric with a broader group of North American species treated as Symphyotrichum (detailed comments below). A number of other genera have been segregated from Aster prior to 1980 and are now generally accepted as distinct; many of these have been as- signed to scattered phylogenetic positions (e.g., Grau 1977; Zhang & Bremer 1993; Nesom 1994e). Among them are (for example) the New World gen- era Diplostephium and Oritrophium (Hinterhuberinae), Machaeranthera and Xylorhiza (Machaerantherinae), and Noticastrum (Chrysopsidinae), as well as Old World groups such as Felicia (Feliciinae), Olearta (Hinterhuberinae), Het- eropappus and Kalimeris (Asterinae), and others noted in the following dis- cussion. In the following and preceding comments, if a species or other infrageneric taxon is not provided with an authority, the full, formal name can be found in the taxonomic summaries (Appendices I and II). Authorities for genera of Astereae can be found in Nesom (1994e). ASTER S. STR. AND ITS ASIAN RELATIVES I. Overview of Aster in Europe and Asia There are about 180 species of Aster s. str. in the Old World (including the seventeen of the African A. harveyanus group, see below). The Northern Hemisphere species are natively concentrated mostly from the Himalayan re- gion of Tibet (Sikang Province, China) and Nepal eastward in China through 150 PHYTOLOGIA volume 77(3):141-297 September 1994 Yunnan Province and Sichuan Province to Guangdong and Taiwan; consider- ably fewer species occur in east-central and northeastern China. Relatively few species of Aster, including the generitype, are centered in Europe or extend across northern Asia into western Europe. Most of these that have been iden- tified as Aster s. lat. are in the groups regarded here as the genera Crinitarza (= Linosyris) and Galatella. Only a single species of Old World Aster, A. alpinus, reaches the New World. Symphyotrichum (Aster, Brachyactis) ciliatum (Lindl.) Nesom and Eurybia (Aster) sibirica (L.) Nesom also have ranges that include both Asia and North America, but the phyletic origins of these two species lie in the New World and their extension across the north Pacific into Asia apparently is relatively recent. Primary, broad sources of systematic and floristic information on Eurasian Aster include the following: Japan (Kitamura 1937; Ohwi 1965); Korea (Lee 1979); China (Hu 1965; Ling, Chen, & Shih 1985); Himalayan area (Grierson 1964); USSR (Tamamschyan 1959); Europe (Merxmiiller et al. 1976; Wagenitz 1979). Other references are found throughout the discussions here. The segregation of Galatella, Crinitaria, Asterothamnus, Krylovia, and other generic-level taxa previously included within a heterogeneous Old World Aster (Table 1) is apparently only recently reaching acceptance. The treatment of Chinese Astereae by Ling et al. (1985) appears to approach the presentation of monophyletic taxa, but anomalous elements with Asian Aster remain to be evaluated more closely. Some of the Aster “series” described by Ling (in Ling et al. 1985) are more distinctive than others and ‘heir taxonomic rank needs to be evaluated in a broad context. But after the exclusion of a few, small, disparate elements from Aster s. str. (see suggestions below), the genus appears to be more internally homogeneous. Even then, however, there is no firm evidence or explicit hypothesis that Old World Aster is monophyletic. Grierson (1964) apportioned the Himalayan species of Aster among three sections: Aster, Orthomeris, and Alpigeni, the latter with four subsections. Ling et al. (1985) treated all of the ca. 135 Chinese species in the same three sections as Grierson, creating a number of infra-sectional categories (as “se- ries”) to accommodate the range of variation in each section. A provisional summary of the proposed, broad taxonomic structure of Aster s. str. is out- lined in Appendix I. Some of the most conspicuous problematic species and species groups are discussed in the sections that follow below. Il. Aster sect. Aster and close relatives The type of Aster is A. amellus L. (as lectotypified by Britton in Britton & Brown 1913; see Hitchcock & Green 1935), a species of southern Europe into west-central Asia. There are relatively few species clearly closely similar Nesom: Review of Aster taxonomy 151 to A. amellus (see sect. Aster, Appendix I), including A. amellotdes Bess., A. catalaunicus Willk. & Costa, A. ibericus M. Bieb., A. indamellus Grier- son, A. peduncularis Wall. ex Nees, and a few others, these mostly from Eu- rope to the Himalayas. Aster amellus and the Himalayan A. thomsoniu C.B. Clarke are the parents of a well-known horticultural hybrid of Europe (Gri- erson 1964). Ling et al. (1985) have considerably broadened the concept of sect. Aster with the addition of other species groups whose relationship to A. amellus is less clear. Aster amellus and its closest relatives are characterized especially by the following features: stems leafy, bearing a few heads in a loose corymb, sometimes reduced to monocephaly; phyllaries broad, graduated in ca. 3 series, somewhat indurated below, herbaceous above but mostly without a strongly demarcated, green apical patch; disc corollas tubular, the tube ca. half the corolla length, abruptly ampliate, with spreading-reflexing lobes; style appendages short, nearly deltate, closely papillate; achenes obovate, strongly flattened, with two, thickened, lateral ribs, the faces commonly with sessile glands near the apex; pappus bristles in 2-3 series, those of the inner series sometimes apically dilated, the outer series of short setae or bristles reduced in length. The achenial morphology of Aster amellus is significant, as this feature is emphasized in the present investigation of subtribal boundaries and the definition of monophyletic lineages. As observed by Grierson (1964, p. 77), the achenial morphology of Asters. str. is notably conservative: “Apart from size, the achenes show little variation throughout the genus. They are all of the bilaterally compressed type with two marginal ribs or with an additional rib on one or both sides as in A. trinervius D. Don, and sometimes with six tibs in A. albescens.” The taxonomic position of the latter species is discussed below, where it is suggested that it is phyletically separate from most of Old World Aster. Aster amellus was placed by Semple & Brouillet (1980a) in Aster subsect. Aster with the North American species treated here as Eurybia sect. Calhias- trum, emphasizing their production of a corymboid capitulescence and broad phyllaries with a basally truncate apical patch. The present treatment, how- ever, concludes that these similarities are convergent or widely parallel. The same conclusion holds for the NOR chromosome morphology of these species, which is implied to be similar according the taxonomy of Semple & Brouillet (1980a) (but see discussion below of NOR chromosomes for other references regarding A. amellus). Jones (1980a) also noted that the North American species most closely resembling A. amellus are among those of sect. Callzas- trum, but this putative proximity was ambiguous in the analysis by Jones & Young (1983). 152 PHY FOLO GLA volume 77(3):141-297 September 1994 Aster sect. Macrocephalht Aster maackti Regel has been segregated as Aster sect. Macrocephal (Ap- pendix I) by Jones (1980a). This species, which occurs in Japan, Korea, and Manchuria, is distinctive in its relatively tall stature (4-9 dm tall), sessile, serrate cauline leaves, long rays, and its elliptic-obovate, distally foliaceous phyllaries with purple scarious margins and a pair of large, lateral gland-like swellings near the apex. In floral and fruit morphology, however, as well as aspects of phyllary morphology, A. maackwz resembles A. amellus and some of its close relatives (sect. Aster) as much or more than any other species. It is here maintained within sect. Aster, where Ling et al. (1985) have recently positioned it. Jones (1980a) and Ling et al. (1985), following Kitamura (1937), placed Aster tataricus L. f. with A. maackii in sect. Macrocephali. Plants of these two species, however, have lanceolate, slightly keeled phyllaries without a foliaceous apex, subterete, 6-7-nerved achenes with a multiseriate pappus of even length bristles, and they are regarded here as only distantly related to A. maackit (see discussion below, “The Aster tataricus group”). Aster sibtricus also has been placed with these species, but it is here included within Eurybza. Aster sect. Alpigent Aster alpinus L. (the type of sect. Alpigeni, see Appendix I) is similar to A. amellus in the morphology and glandular vestiture of its achenes and its externally differentiated pappus. Putative hybrids have been reported between these two species (e.g., see Tamamschyan 1959, p. 111-112). Plants of Aster alpinus are strictly monocephalous, and the phyllaries differ from those of A. amellus in being oblong-lanceolate, completely herbaceous, and arranged in 2(-3) series of nearly equal length, and the lobes of the disc corollas are relatively short and erect. The pappus of A. alpinus commonly has a shorter, outer series, but the degree of differentiation is variable. Aster alpinus ranges from northern Europe eastward across Asia and ap- parently is the only species accepted here as Asters. str. that reaches North America, where (as A. alpinus var. vierhappert [Onno] Cronq.) it occurs spo- radically from Alaska to Colorado (Cronquist 1955; Hultén 1968; Weber & Wittman 1992). Aster culminis A. Nelson (the type from Colorado) is a syn- onym of A. alpinus var. vierhapperi (Weber & Wittman 1992). The wide vari- ability in A. alpinus and its correspondingly complex taxonomy was discussed in detail by Onno (1932) and more recently summarized by Tamamschyan (1959), who recognized some of the more distinct subspecific taxa at specific rank. Aster pyrenaeus (Desf.) ez DC. of central Europe closely resembles A. alpinus. Grierson (1964) observed that A. alpinus does not reach the Hi- malayan region, but sect. Alpigeni is represented there by A. tricephalus C.B. Nesom: Review of Aster taxonomy 153 Clarke and its allies (nine species in the Himalayas), which Grierson divided between subsect. Homochaeta and subsect. Heterochaeta. Most of the species included by Onno (1932) in his delineation of Aster sect. Alpigent were Old World Aster, but also included were American species of Eurybia, Symphy- otrichum, Xylorhiza, and Erigeron. Ling et al. (1985) have suggested further broadening of sect. Alpigent within Aster s. str. Subdivisions of sect. Alpigenit based on variation in pappus morphology ap- parently are largely artificial; the subsections recognized by Grierson have been combined by Ling et al. (1985) as subsect. Alpigent and placed in coordinate position with a group with the suggested name (but unvalidated) “subsect. Senecioides” (see Appendix [). Regarding Aster alpinus, Cronquist (1955, p. 76) observed that, “Although it is necessarily included in Aster, this species approaches Erigeron in habit, achenes, and early flowering.” The broadly obovate shape of the achenes and the presence of achenial glands, as well as the disc corolla shape, however, are anomalous within Erigeron. The similarity between A. alpinus and Erigeron has resulted from evolutionary convergence (see detailed comments above). Aster sect. Ageratoides The group of Old World species previously treated within Aster sect. Or- thomeris is here regarded as Aster sect. Ageratoides, typified by A. ageratoides Turcz. (see Appendix I). Sect. Orthomeris s. str. becomes a synonym of the North American genus Oclemena (see discussion below). Plants of sect. Ageratoides are characterized by flexuose stems, particu- larly in the capitulescence, toothed, often 3-veined leaves, the surfaces com- monly sessile-glandular, heads in a corymboid capitulescence, lanceolate, thin- indurate (hardly herbaceous) phyllaries often with orange veins, and abruptly ampliate disc corollas. They are remarkably similar to Oclemena, but the disc achenes of the Asian species are flat and 2-nerved, although the ray achenes may be 3-4 nerved. Other differences are found in the morphology of the phyl- laries, disc corollas, and pappus (see discussion of Oclemena, below). Never- theless, the resemblance between sect. Ageratoides, Oclemena, and Eucephalus suggests that Old World Aster should be investigated for the possibility that it is polyphyletic. Ling et al. (1985) have added a number of small, peripheral groups to sect. Ageratoides, but it is considerably more homogeneous with the suggested re- moval of A. albescens (DC.) Hand.-Mazz. and its close relatives (see below, “The status of Aster albescens), which have been included by both Grier- son and Ling within sect. Ageratoides. Aster molliusculus (DC.) C.B. Clarke, which was treated by Ling et al. as the monotypic ser. Molhusculi within sect. Ageratoides, resembles the African species placed here in Aster sect. Cal- wmeridet. 154 PHYTOLOGIA volume 77(3):141-297 September 1994 III. Aster in Africa Many species of southeastern Africa were originally described as Aster, but most of these have now been transferred to the Astereaean genera Felicia (Grau 1971, 1973), Polyarrhena (Grau 1970), and a few others. A group of five Madagascan species described as Aster has been segregated as the genus Madagaster (Nesom 1993a). Only one group of seventeen native African species is still currently accepted as Aster, the “A. harveyanus group” (or the “A. bakeranus Burtt Davy ez C.A. Smith group”), these treated in detail by Lippert (1971, 1973). One species is recently added (Hilliard & Burtt 1985) and one transferred to the genus Macowania Oliv. of the Inuleae (Burtt & Grau 1972; Hilliard & Burtt 1976). In Grau’s study of Felicta (1973), his graphic depiction of its close relatives (p. 251) placed the Aster harveyanus group (as the genus Aster) in a close relationship with other South African genera. He was unwilling to formally segregate this group without a broader survey of Aster, but he noted (1971, p. 279) that ”there is still lacking a valid generic name for the herbaceous ‘Diplopappi’.” The generic name Diplopappus Cass., which has been applied to the South African species of Aster sensu Lippert (e.g., de Candolle 1836; Harvey 1865), must be typified by a North American species (Nesom 1993g). In any case, however, the species of the A. harveyanus group do not appear to be closely related to other African genera of Astereae (Nesom 1994e). De Candolle (1836) treated Diplopappus asper Less. (= Aster bakeranus) within his Diplopappus sect. Calimeridet; the other species of this section (sensu DC.) are Himalayan taxa accepted by Grierson (3964) as true Aster, including A. molliusculus and A. trinervius (both placed by Grierson in sect. Orthomeris) and A. peduncularts (placed by Grierson in sect. Aster). The one remaining species of de Candolle’s sect. Calimeridei is now treated as a species of the genus Kemulariella (K. caucasica {Willd.] Tamamsch.) (Tamamschyan 1959). I have not been able to find any morphological character that would un- equivocally eliminate the Aster harveyanus group from Aster s. str., particu- larly in view of its close similarity to the Asian species A. molliusculus, which appears to be closely related. Aster harveyanus and close relatives produce flat, 2-nerved, obovate achenes with glands scattered over the surfaces, a bis- eriate pappus (inner series of persistent, barbellate bristles, the outer series short and scaly), and thick, mostly herbaceous phyllaries. They constitute a distinctive phylad characterized by thick, 3-nerved, entire, mostly cauline leaves with a subclasping base, solitary heads on long peduncles, disc corol- las with short and sharply reflexing lobes, and thickened, nearly tuberous, fibrous roots. The group is endemic to grasslands at moderate elevations in the Afromontane floristic region, an elongate series of isolated highland areas in southeastern Africa (see summary by Goldblatt 1978; Killick 1978). Nesom: Review of Aster taxonomy 155 Outside of the Aster harveyanus group, no other species of typical Aster occurs in Africa as part of its native distribution. In the present interpreta- tion, from an origin in Himalayan Asia, the “harveyanus” ancestral complex probably migrated southward along the mountains of the eastern margin of Africa, where it remains extant only in the southernmost region, reaching as far as the Drakensberg Mountains. This distinctive group is provided here with the formal designation of Aster sect. Calimeridei, validated in Appendix I. IV. Problematic species in Aster Some species of Old World Aster that have been treated as generic seg- regates or else suggested to be potentially distinct are tentatively maintained here within Aster (see Appendix I, Aster Incertae Sedis). These and other problematic species are discussed in the following subtopics. The status of Bellidiastrum, Bellis, and Bellium Aster bellidiastrum (L.) Scop. , a species sometimes segregated from Aster as the monotypic genus Bellidiastrum (as B. michelii Cass.) is similar to typical Aster in its achene and pappus morphology and to some species of Aster in its monocephalous habit, phyllaries of nearly equal length, and short disc corolla lobes. The distinctiveness of A. bellidiastrum was early perceived, as it received at least three other names (besides Bellidiastrum) at generic rank. It occurs in south-central and southeastern Europe, where it is distinguished from other Old World species particularly by its combination of a scapose, monocephalous habit, spatulate, eglandular leaves in a basal rosette, conical receptacles, and achenes fully pappose with barbellate bristles. De Jong (1965, p. 487) observed that Aster bellidiastrum (as the genus Bel- lidiastrum) is most closely related to Bellis L. and Bellium L. “on the basis of the scapose habit, spathulate toothed or entire radical leaves, herbaceous, bis- eriate phyllaries, and ribbed achenes which the three genera have in common.” In addition, they also are similar in their phyllaries of completely herbaceous texture, short and erect disc corolla lobes, short and papillate collecting ap- pendages atop markedly short style branches, and a biseriate pappus. Plants of A. bellidiastrum, Bellis, and some species of Bellium are scapose (caulescent in some species of Bellium), and all species of these three genera are mono- cephalous. Aster bellidiastrum, however, produces a well-developed pappus of barbellate bristles, often with a short, outer series of setae, in contrast to the scales and bristles in Bellium and relatively reduced pappus in Bellis, and the treatment of Bellidiastrum and Aster as congeneric apparently has emphasized their similarity in this plesiomorphic feature. If A. bellidiastrum is accepted 156 PHYTOLOGIA volume 77(3):141-297 September 1994 as a species of typical Aster, it must be with the hypothesis that it is spe- cialized in its reduced habit and involucre. But its seemingly isolated position within Aster and its remarkable resemblance to Bellis, including the conical receptacles, suggests that its relationships and taxonomic position should be investigated in more detail. It may prove best regarded as a monotypic genus or even included within Bellis. Bellis has been treated as the monotypic subtribe Bellidinae (Nesom 1994e), emphasizing its rosulate leaves, scapose, monocephalous stems, conical re- ceptacles, herbaceous, pauciseriate phyllaries, and flat, essentially epappose achenes. Bentham (1873) noted possible points of phylogenetic connection be- tween Bellis and other genera such as Grangea, Lagenifera, and Brachycome, each recently considered (Nesom 1994e) to be a member cf a separate subtribe (i.e., Grangeinae, Lageniferinae, and Brachycominae). The current treatment of Bellis recognizes its apparently intimate position among these groups and maintains it at a coordinate rank. Bellium produces a flat to low-hemispheric receptacle, concave phyllaries with scarious margins, an outer pappus of scales. It is similar in these respects to genera of the subtribe Feliciinae, where it has been recently placed (Nesom 1994e), and is apparently only distantly related to Bellis and Aster. The status of Aster fastigiatus (= Turczaninowia) Aster fastigiatus Fisch. was segregated as the monotypic genus Turczant- nowia by de Candolle in 1836. It has generally been treated within Aster, but Tamamschyan (1959), Ling et al. (1985), and Bremer (1994) have accepted it as a separate genus. This species, which occurs in eastern Asia (Japan and Korea to Mongolia, Manchuria, and eastern Siberia), is briefly characterized as follows: perennial or biennial herbs, the stems few-branched until the capit- ulescence; leaves linear to narrowly lanceolate, entire, evenly arranged along the stems; stems and undersurface of leaves densely and minutely strigillose with thick hairs, the vestiture often completely obscuring the surface, the leaves also minutely granular-glandular; heads small (5-8 mm wide) in dense terminal corymboid clusters; phyllaries in 2-3 graduated series, not keeled; ray flowers fertile, white, usually fewer than 10 in number, barely extending past the involucre; disc corollas with a narrow tube abruptly ampliate into the limb, the lobes long and coiling-reflexing, style branches with short, papillate collect- ing appendages, the inner flowers sometimes functionally staminate; achenes 1.0-1.2 mm long, obovate-oblong, 2-nerved but plump, the surfaces glandu- lar and slightly strigose; pappus of (1-)2 series of equal-length bristles, with attenuate apices; chromosome number, n=9. Among the most remarkable features of plants of Aster fastigiatus are their dense vestiture and small heads (with flowers and fruits reduced correspond- Nesom: Review of Aster taxonomy 157 ingly) in a compact capitulescence, but these are qualitative differences com- pared to other Asian species of Aster. In most floral and fruit characters, there is nothing to exclude A. fastigiatus from sect. Ageratoides. The ovarian sterility of the inner disc flowers may be a specialization connected with the reduction and compression of the flowers within a small head. Similar tenden- cies for reduction of heads, flowers, and fruits (except for the sterility) occur in other species of Aster (e.g., A. sampsonzi (Hance) Hemsl. of southern China), and it is difficult to segregate A. fastzgzatus on this basis. Following the sug- gestion of Tamamschyan (1959), however, the possibility of a close relationship between A. fastigiatus and Galatella needs to be investigated. The status of Aster bipinnatisectus Aster bipinnatisectus Ludlow in Grierson is endemic to rock faces in south- eastern Tibet at 3200 meters elevation and was placed in the monotypic sect. Bipinnatisecti by Grierson (1964) in connection with the original description of the species. Most recently, however, Ling et al. (1985) have reduced sect. Bipinnatisect: in rank and treated it within sect. Aster as ser. Bipinnatisecti. The species is briefly characterized as follows: dwarf, caespitose, perennial herbs from stout taproot and short woody caudex branches, leaves bipinna- tisect, in a basal rosette, densely white-sericeous, the hairs forming “dense cottony balls at the top of the rootstock” (the leaf bases), heads solitary, ray and disc flowers fertile, the rays light purple, and densely sericeous achenes with an inner pappus of slender setae and outer pappus of stout subpalea- ceous setae. It resembles Machaeranthera in habit and leaf morphology, as noted by Grierson, but its pappus and phyllary morphology place it closer to the Asterinae than any New World groups. Aster bipinnatisectus appears to be morphologically isolated within Aster, but its habit is more common in other genera of the subtribe, e.g., AKrylovia, Psychrogeton. The peculiarities in vestiture of A. bipinnatisectus, however, suggest that a close relationship to the Hinterhuberinae should be investigated, although such a relationship seems unlikely on a geographical basis. The status of Aster lanuginosus (Wardaster) and Aster prainiu ( Chlamydites) The monotypic genus Wardaster (Small 1926) was originally collected from south-central China near the Szechuan- Yunnan border on “high cliffs and boul- der screes of slate” at 15,000 feet elevation. It is briefly characterized as follows (as described and illustrated by Small 1926): dwarf, densely lanate, rhizomatous perennials with spatulate, entire basal leaves and short-scapose monocephalous stems prominently thickened just below the heads; heads with phyllaries in 3 series nearly equal in length; receptacles alveolate; ray flowers 158 PHYTOLOGIA volume 77(3):141-297 September 1994 with lilac-violet ligules ca. 15 mm long; style branches of the disc flowers with papillate, deltate collecting appendages; bases of the anther thecae with short tails; achenes obovate-oblanceolate, flattened, 2-nerved, and 2.5-3.0 mm long. Wardaster (Aster lanuginosus [J. Small] Y.L. Chen) is similar to A. alpi- nus and other species of typical Aster in habit (monocephalous, leaves mostly basal), but it is anomalous in vestiture. Further, the anther morphology sug- gests that the possibility of a relationship with the Hinterhuberinae should be investigated. In Grierson’s examination of Wardaster, however, he observed (p. 75) that the anther bases “seem to be only slightly longer and more pointed than those of A. flacctdus subsp. tsarungensis or A. fuscescens which have an- thers of comparable size.” é Another monotypic genus remarkably similar in habit and vestiture to Wardaster was described earlier by J.R. Drummond (1907) from southeast- ern Tibet: Chlamydites. These plants were described as having phyllaries connate toward the base, rays apparently yellow, anther thecae without tails, and linear, “subcompressed,” particularly large achenes (6-8 mm long). The “true affinity” of the species was hypothesized in the original description to be with the Chinese-Nepalese genus Cremanthodium Benth. (Senecioneae - Tus- silagininae). Recently, however, Chlamydites prainit J.R. Drumm. has been transferred to Aster and placed with Aster lanuginosus as Aster {sect. Alpi- geni| ser. Prainiana by Ling et al. (1985), who used the tailed anthers as one of the characters separating these from other species groups. Further, they described the ray color of A. praintit (J.R. Drumm.) Y.L. Chen as deep blue and the achenes to be 3 mm long, in contrast to the original description. The taxonomic position of both of these species needs further study. The status of Aster albescens and Aster ser. Albescentes Aster albescens is a widespread species that occurs in northwest India, Kashmir, Nepal, and Tibet, and then to Burma and Assam. It is briefly char- acterized as follows: commonly woody-stemmed subshrubs or shrubs 0.3-2.0 meters or more in height; leaves narrowly elliptic-lanceolate, sessile to dis- tinctly short-petiolate, entire to serrate, closely pinnate-veined with relatively straight laterals, the margins often revolute; stems and lower leaf surfaces of- ten closely and densely white-tomentose, punctate-glandular beneath the to- mentum with sessile, resinous glands, (or) tomentum absent and the surfaces only glandular, (or) the surfaces eglandular; heads relatively small, 5-7(-9) mm wide and borne in tight corymbs; phyllaries broadly lanceolate, keeled, strongly graduate in length, stramineous, relatively even-textured, the mar- gins sometimes purplish; rays white to bluish, not coiling; disc corollas lobes long and recurving-coiling, sometimes shorter and somewhat erect; disc style branches with closely papillate collecting appendages; achenes fusiform to nar- rowly obovoid, terete, (4-)6-nerved, 1.5-2.0 mm long, glabrate to short-strigose, Nesom: Review of Aster taxonomy 159 sometimes minutely glandular, the glands caducous but visible at least before fruit maturity; pappus of 1-2 equal length series of apically dilated bristles, commonly with a few short setae in an additional outer series. Many varieties have been recognized within Aster albescens (see Grierson 1964, p. 109): “Leaf shape, size and indumentum are variable in this species as is also the size and shape of the capitulum, phyllaries and ligules. Coloration of the ligules and phyllaries is likewise often a distinctive but variable feature of these plants. There is little apparent correlation between these characters ” Grierson (1964) described a Tibetan species closely resembling Aster albes- cens. According to him (1964, p. 111), A. fulgidulus Grierson “is obviously telated to A. albescens from which it differs in its larger ovate leaves with their glistening areas of epidermis over and between the minor veins on the lower surface.” Aster fulgidulus is more restricted in distribution (known only from southeast Tibet) and is apparently much more uniform in morphology than A. albescens. Both A. albescens and A. fulgidulus are illustrated in Grierson’s treatment. More recently, Ling et al. (1985) segregated these two species with yet four others as Aster (sect. Orthomeris] ser. Albescentes (see Appendix I). Ser. Albescentes appears to be isolated among Old World Aster. Its keeled phyllaries, terete and multinerved achenes, and pappus bristles with a tendency for dilated apices suggest that it is more closely related to the North Amer- ican groups, where it would be positioned near Doellingeria (Figure 1). As noted below (see “The Northern Hemisphere Subtribes”), this group of genera and species may constitute a basal “grade” only slightly removed from an- cestral stock here hypothesized to resemble Hinterhuberinae. Ser. Albescentes resembles Eucephalus in its closely tomentose vestiture and keeled phyllar- ies; it resembles Doellingeria in achene morphology, Ocleinena in its tendency for glandular achenes (but this also common in Asters. str.), and Oclemena and Sericocarpus in sessile-glandular leaves (this feature also in Aster s. str.). Plants of ser. Albescentes are habitally distinct (as woody-based shrubs) and have other characters in a combination not found in other North American taxa. Clarke (1876) placed Aster albescens within the genus Microglossa (Baccha- ridinae sensu Nesom 1994e), presumably influenced by the resemblance of these plants in shrubby habit, large, distinctly petiolate, and prominently pinnately veined leaves, relatively small heads in close corymbs, and relatively small, cylindrical, multinerved achenes. Previous ambiguity in the generic placement of A. albescens reinforces the suggestion that it (with ser. Albescentes) is iso- lated among Asian Astereae. In the tentative view here, the segregation of ser. Albescentes at generic rank apparently would be justifiable. 160 PY T OT-OGTSA volume 77(3):141-297 September 1994 The Aster tataricus group Aster tataricus and A. faureri Levl. & Van. (sensu Kitamura 1937) are con- sidered here as the “A. tataricus group” (see Appendix I). The two are closely similar and have been considered varieties of a single species (see Kitamura 1936, 12:534.). Aster tataricus occurs in northeast Asia and is widely natural- ized in the eastern United States, where it has escaped from cultivation. Aster faureri is endemic to the Manchurian region. These plants are briefly char- acterized as follows: perennials mostly 0.8-2.0 m tall, stems herbaceous, with numerous, prominent, raised ribs; leaves eglandular, thick, the basal persistent, elliptic, with a broadly winged petiole, the cauline subpetiolate, not clasping, the lower coarsely and evenly serrate, becoming entire upward; heads numer- ous in a loose, broadly paniculate to corymboid capitulescence, the terminal branchlets with heads in corymboid clusters; receptacles prominently alveolate; phyllaries lanceolate with acute apices, in 5-6 series slightly to strongly gradu- ate in length, herbaceous, 1-nerved, with a green band along the midvein from base to tip, often purple-margined, often distinctly low-keeled; rays bluish, not coiling; disc corollas abruptly ampliate, with long, reflexing-coiling lobes; disc style branches with papillate, deltate-triangular collecting appendages; achenes fusiform to broadly ellipsoid or obovoid, 1.5-2.0 mm long, terete, (4-) 5-7 nerved, glabrous to sparsely short-strigose, eglandular, the fruit wall often becoming purplish; pappus of 2 series of apically attenuate bristles of equal length; base chromosome number, z=9. Plants of the Aster tataricus group generally have been placed with A. maackt within ser. (or sect.) Macrocephali (e.g., Kitamura 1936, 1937; Jones 1980a; Ling et al. 1985), but A. maackii has phyllaries with broad, folia- ceous apices and flattened, obovate, 2-nerved achenes and is closely similar to species of sect. Aster (see comments above). The A. tataricus group might be retained within Aster s. str. as an isolated element, but the keeled phyl- laries and terete achenes suggest that the closest relatives of the group are among North American species. The phyllaries and achenes are particularly suggestive of Doellingeria. V. Delimitation of the Asterinae s. str. The species of the Asian genera placed here in the Asterinae (Table 1) have almost all been formerly treated as congeneric within Aster (as have the Amer- ican species). The monotypic Arctogeron was originally described by Linnaeus as Erigeronand much later transferred by Komarov to Aster; Psychrogeton has been treated within Erigeron (see below). Psilactis has been treated within Machaeranthera. The Asterinae is briefly characterized as follows: perennial herbs, sometimes with a woody base; capitulescence corymboid, often reduced Nesom: Review of Aster taxonomy 161 Table 1. Composition of subtribe Asterinae. The date of publication and an estimate of the number of constituent species are indicated in parenthesis for each accepted genus. Additional synonyms for accepted genera can be found in Appendices I and II. 1. Aster group Aster L. 1753 (ca. 180) 2. Kalimeris group Kalimeris (Cass.) Cass. 1822 (8) SYN= Asteromoea (Blume) Makino 1898 Callistephus Cass. 1825 (1) Heteropappus Less. 1832 (20) Miyamayomena Kitam. 1982 (6) SYN= Gymnaster Kitam. 1937, non Schutt 1891 Boltonia L’Herit. 1789 (5) 3. Galatella group Galatella Cass. 1825 (30) Crinitaria Cass. 1825 (13) SYN= Linosyris Cass. 1825, non Ludw. 1757 SYN= Pseudolinosyris Novopokr. 1918 Tripolium Nees 1832 (1) 4. Asterothamnus group Asterothamnus Novopokr. 1950 (7) Kemulariella Tamamsch. 1959 (6) Krylovia Schischk. 1949 (4) Psychrogeton Boiss. 1875 (20) Arctogeron DC. 1836 (1) 162 PHY T OTOGiA volume 77(3):141-297 September 1994 Table 1 continued. 5. Eurybia group Eurybia (Cass.) S.F. Gray 1821 (28) Sericocarpus Nees 1832 (5) Oreostemma E. Greene 1900 (3) Ampelaster Nesom 1994 (1) Psilactis A. Gray 1849 (6) Almutaster Love & Love 1982 (1) Canadanthus Nesom 1994 (1) Symphyotrichum Nees 1832 (95) 6. Doellingeria group Doellingeria Nees 1832 (11) Oclemena E. Greene 1903 (3) Eucephalus Nutt. 1841 (11) 7. Jonactis group Tonactis E. Greene 1897 (5) 8. Incertae sedis Chloracantha Nesom, Suh, Morgan, Sundberg, & Simpson 1991 (1) Tonestus A. Nelson 1904 (8) Nesom: Review of Aster taxonomy 163 to monocephaly or sometimes modified as an open panicle; rays white, yellow in some taxa of Psychrogeton; achenes obovate, flattened, 2-nerved, often with glandular faces; pappus multiseriate, the outer series commonly shortened; base chromosome number, z=9, without exception. All groups except two are primarily restricted to Asia: Boltonta is North American and Aster sect. Calimeridet is African. Fourteen genera are formally recognized here, but six distinctive generic-level groups (see Appendix I), each potentially given generic status, are recognized and discussed. Two of these, which produce terete ach- enes, may be more closely related to species placed here in New World genera. A. The status of Boltonia and Kalimeris Boltonia s. str. is an eastern North American genus of five species (Ander- son 1987). Bentham (1861, 1873), however, viewed these New World species as so close to those of the Asian genus Kalimeris that he considered them all congeneric. In contrast, Gray (1884) limited Boltonta to only the American species, and botanists since then have merged or separated the two genera in various combinations or else treated Kalimeris within Aster while keeping Boltonia separate. Recently, for example, Grierson (1964) considered Boltonia and Kalimeris congeneric, while Grau (1977) regarded them as separate. A revisional study of Kalimeris (Gu 1987, in press) has defensibly maintained the two as separate genera, based on the winged achenes and slightly differ- ent pappus morphology of the New World plants, but they are otherwise so similar in morphology that a hypothesis of close relationship between them is reasonable. Boltonia is morphologically isolated in the New World, although it has been placed by Zhang & Bremer (1993) as closely related to genera treated by Nesom (1994e) within the subtribe Brachycominae. The closest relatives of Kalimeris, in contrast, apparently are more easily discerned and include a group of small Asian genera that have been segregated as satellites of Aster, in- cluding Heteropappus, Miyamayomena, and Callistephus (Table 1). Chung & Kim (1991) included Boltonia as part of this group and noted that the recepta- cles of Boltonia, Kalimeris, and Gymnaster are conical or steeply hemispheric. Natural hybrids are known between species of Kalimerts and Heteropappus (Tara 1973) as well as between Kalimeris and Asian species of Aster (particu- larly A. ageratoides, e.g., Inoue 1970; Tara 1972; Gu 1987). The genera of the Kalimerts group appear to be closely related among themselves and to typical Aster, both on genetic and morphological grounds. From this perspective, the cladistic relationship of Boltonia is here hypothesized to be as close or closer to Asters. str. than to any of the North American taxa segregated from Aster in the present study. 164 PHY: FT ODO A volume 77(3):141-297 September 1994 Notwithstanding the hypothesis here of its close relationship to Asterinae, Boltonia produces short-tubed disc corollas with orange veins more like South- ern Hemisphere groups, including Brachycominae, and the relatively small, scarious-winged achenes also are more consistently placed in the latter sub- tribe. Boltonia is further anomalous in the Asterinae in its pappus elements, which are of two lengths but not clearly in more than a single series; the phyl- lary midrib tends to be orangish, thick, and distinctly raised, and the habit also is reminiscent of the North American Chloracantha and Eurybia (Aster) chap- manii (Torr. & Gray) Nesom. A karyotype of Boltonta might produce valuable evidence of relationship, as the NOR chromosomes would be predicted to be of the Asterinae type (see discussion below) and distinctly different from those of American asters. The Kalimeris group Callistephus and Miyamayomena tend to produce broadly obovate leaves with coarsely and widely dentate margins, short-tubed disc corollas with short lobes and short, papillate collecting appendages of the style branches, and they have a tendency for reduction of the pappus. Callistephus has caducous bristles; Miyamayomena is essentially epappose; the capitulescence is reduced in both. The similarity in habit and general appearance, as well as the similar tendency for pappus reduction, between these genera and some species of Myr- tactis (Lageniferinae) is remarkable. In general, plants of these genera produce a loosely organized capitulescence (like the American Symphyotrichum) rather than a corymboid cyme. Heteropappus is more similar to Boltonia and Kalimeris in its habit and loosely paniculate capitulescence, and the achenes commonly produce a dis- tinctly biseriate pappus, the outer series of scales. In all species of Heteropap- pus except H. altaicus (Willd.) Novopokr., the ray achenes are epappose or have a reduced pappus. Species of Kalimeris form natural intergeneric hy- brids with Heteropappus (Huziwara 1950; Tara 1973) and Aster (Inoue 1970; Tara 1972, 1979). B. The status of Galatella and Crinitaria The Eurasian groups Aster sect. Galatella (Cass.) Reichenb. (= Galatella) and Aster sect. Linosyris (Cass.) O. Hoffm. (= Crinitaria) have been treated as within Aster by Merxmiiller et al. (1976) and Wagenitz (1979) but as sepa- rate genera in other studies (e.g., Grierson 1975; Grierson & Rechinger 1982; Tamamschyan 1959; and a recent checklist of Asteraceae of the USSR (Cher- panov 1981]|). Galatella includes, for example (by their names in Aster), A. albanicus Degen, A. aragonensis Asso, A. sedifolius L., A. punctatus Waldst. & Nesom: Review of Aster taxonomy 165 Kit., and A. canus Waldst. & Kit.; Crinitaria includes A. linosyris (L.) Bernh. and A. oleifolius (Lam.) Wagenitz. These two generic-level taxa were posi- tioned by Jones & Young (1983) among the initial, primitive branches of Aster most closely related to sect. Janthe and sect. Eucephalus but within a group that included Doellingeria as well. Similarly, Semple & Brouillet (1980a) sug- gested that Galatella and Crinitaria should be placed in “subgenus Jonactis,” which in their view included both Jonactis and Eucephalus. Both Galatella and Crinitaria have features (or at least tendencies) that indicate their close relationship to typical Aster: sessile-glandular leaves, disc style branches with relatively short (triangular-deltate) densely papillate col- lecting appendages, and flat, obovate, 2-(4-)ribbed achenes with the faces of- ten glandular at least near the apex. Particularly in their glandular-punctate leaves and flat-topped capitulescences of relatively small heads, these taxa have a superficial resemblance to genera of North American Solidagininae, and I suggested (Nesom 1991d) that Galatella and Crinitaria might belong within the Solidagininae. With additional perspective, however, it appears that such similarities have developed in parallel and that Galatella and Crinitaria are more closely related to typical Aster. Galatella and Crinitaria are distinct in morphology and set apart from other groups of Aster. Plants of both genera have a strong tendency to produce glandular herbage, strongly single-veined leaves, and broad, parallel- nerved phyllaries. Those of Galatella have sterile ray flowers usually with white to blue, non-coiling ligules, relatively shallow disc corolla lobes, and an essentially uniseriate pappus. Those of Crinitaria usually completely lack ray flowers, produce disc corollas with long, somewhat coiling-reflexing lobes, and a multiseriate pappus. As noted by Tamamschyan (1959), there are a num- ber of relatively discrete morphological groups in both genera and the inter- relationships among them are not clearly understood, suggesting that generic boundaries may yet be redefined. Pseudolinosyris of central Asia is one of these subgroups, separated from Crinitaria by narrowly lanceolate stylar col- lecting appendages and narrower, multinerved achenes; it is here tentatively included within Crinttaria. C. The status of Aster tripolium (= Tripoltum) Another species of Eurasian Aster that has with some justification been treated as a monotypic genus is A. tripolium L. (= Tripoltum vulgare Nees = Tripolium pannonicum |Jacq.| Dobrocz.). This species is most commonly found in saline habitats of sea coasts and coastal marshes and around in- land salt lakes. It occurs from northern Europe southward to Italy and North Africa, from there to Turkey, northern Iran, and the Caucasus region, and then apparently scattered eastward across Asia to the Pacific coast from central 166 PHY TO O:6GiaA volume 77(3):141-297 September 1994 China, Japan, and Korea northward to Manchuria and Siberia. The range of this species is sometimes attributed to North America; the only records I know of from this region apparently were collected as waifs on “ballast” in Philadel- phia, Pennsylvania (23 Sep 1877, Parker s.n. {US!]; Aug 1878, Martindale s.n. [US!]). Tripolium is remarkably specialized in its habitat, annual duration, glabrous, somewhat succulent leaves, and strongly accrescent pappus. It has a superficial resemblance to some species of the New World Symphyotrichum sect. Ozytripolium in habitat and vegetative morphology (glabrous, taprooted annual with thick, entire, and narrowly lanceolate leaves), but the strongly corymboid capitulescence, broad, thin-herbaceous and parallel-veined phyllar- ies in few (1-3) series, and the flat, obovate, 2-ribbed achenes, commonly with a mixture of eglandular and glandular trichomes of Trzpolum indicate that it is related to the species and species groups of Old World Asterinae. Sundberg (1986) noted most of the peculiar morphological features of Tripolum and emphasized its base chromosome number of z=9 in its elimination from sect. Ozytripolium, the latter interpreted by him as strictly an z=5 group. Aster tripolium has mostly been treated within Aster (e.g., Merxmiiller et al. 1976; Wagenitz 1979; Ohwi 1975), where it has been recognized at vari- ous ranks, from sect. Tripolium (Nees) Benth. to a possible member of Aster “subg. Jonactis sect. Eucephalus” (Semple & Brouillet 1980a). Tamamschyan (1959) accepted it as a monotypic genus, as did Zhang & Bremer (1993). Its distinctly corymboid capitulescence, herbaceous, broadly rounded, multiner- vate phyllaries, and tendency for raylessness (e.g., Sterk & Wijnands 1970) are similar to Crinttaria and Galatella and suggest that these taxa may be closely related. Such a combination of features apparently does not occur elsewhere in Aster or its close relatives, and in this interpretation, Tripolium is reasonably treated as a monotypic genus. Within Aster, it is isolated. D. The Asterothamnus group As recognized here, the Asterothamnus group (Table 1) includes a num- ber of relatively small genera characterized as perennials from a woody base, commonly caespitose in habit, the stems and leaves often sessile-glandular and often tomentose, with few or solitary heads and strongly coiling rays. These are segregates of Aster, similar to the latter in the following set of features: glandular vestiture (Krylovia, Psychrogeton, Asian “Brachyactis”); white to bluish rays in a single series; short and papillate collecting appendages of the disc style branches; phyllaries variable in morphology but without an api- cal patch; disc corollas abruptly ampliate, long-lobed in Asterothamnus and Krylovia; achenes obovate and flattened (sometimes 3-angled), the faces com- monly glandular at least near the apex; and pappus multiseriate, the outer series often strongly shortened, the inner bristles sometimes apically dilated Nesom: Review of Aster taxonomy 167 (in Asterothamnus, Krylovia, and Kemulariella). The group occurs primar- ily in central Asia: Asterothamnus and Arctogeron in the steppes of central Asia (Siberia, Mongolia, and China) in open, stony habitats; Krylovia in rock crevices and talus of montane central Asia; Kemulariella in montane Cauca- sus; Psychrogeton and Asian “Brachyactis” in the Himalayas, central Asia, and montane Asia Minor. Grierson (1964, p. 116) observed that Asterothamnus is segregated from Aster on habital and vegetative characters “but is not distinguished by char- acters involving the involucre, flowers, achenes or pappus.” While all of the Aster segregates of the Asterothamnus group certainly are in need of more detailed investigation, the distinctly keeled phyllaries of Asterothamnus and Krylovia set them apart from most other Old World Aster. There is reason to consider the group monophyletic, and the well-defined and well-accepted genus Psychrogeton appears to be a member of it. Continued recognition of Psychrogeton suggests that the others should be accorded coordinate taxo- nomic status. Asterothamnus is a remarkably distinctive genus. The plants are strongly branching subshrubs with revolute-margined, linear or narrowly elliptic leaves, the stems and leaves closely and thinly tomentose and gray-green, and the heads radiate or eradiate and solitary or few in a loose corymb. Plants of Krylovia are caespitose perennials from a taproot and thick caudex branches, producing a persistent basal rosette of broad, toothed, sessile-glandular leaves, and the heads are few or solitary on scapose stems. Krylovia is similar in habit and vestiture to many species of Psychrogeton. Asterothamnus and Krylovia apparently are closely related though markedly different in habit. They are similar in their Eucephalus-like phyllaries, evenly yellow-green or sometimes purple-margined, and with a low but distinct central keel, disc corollas with long, coiling-reflexing lobes, flat, obovate, 2-nerved achenes with glandular surfaces, and a 1-3-seriate pappus, sometimes with a short outer series, the bristles apically attenuate or dilated. Arctogeron has a caespitose habit like Krylovia but is immediately distinct in its stiffly linear-filiform leaves. The single species, A. gramineum (L.) DC., was originally described by Linnaeus as Erigeron, but its resemblance to the latter genus is interpreted here as convergent. Arctogeron differs from Erigeron in its 3-veined phyllaries, differently shaped achenes, and there are no promi- nent resin ducts accompanying the veins of herbage and achenes. There is a strong habital resemblance between Arctogeron and some species of Jonactts, but Arctogeron differs from these in its scapose stems, relatively short and papillate collecting appendages, 3-nerved, unkeeled phyllaries in 3-4 series of nearly equal length, and its consistently flat and 2-nerved achenes. Kemulariella, as defined and treated by Tamamschyan (1959), is a genus endemic to the Caucasus region. It was described as different from Aster in its double pappus (the outer series distinctly shortened and often scaly), 168 PHYTOLOGIA volume 77(3):141-297 September 1994 but a differentiated, multiseriate pappus is also characteristic of many species of Aster, including the type (see previous discussion). Kemulariella caucasica ( Willd.) Tamamsch., the generitype, is very different from the other five species in its tall, herbaceous, solitary stems with large cauline leaves and was placed by Tamamschyan as a monotypic section. The other species of Kemulariella resemble Arylovia in their caespitose habit with woody rhizome and caudex branches and relatively more numerous stems from the base. The definition of Kemulariella and its internal consistency need to be reexamined. Psychrogeton Plants of Psychrogeton are mostly perennial (few annual or biennial), usu- ally with a thick, woody taproot or at least short, woody caudex branches. They are similar to Krylovia in their caespitose habit, and the leaves and stems commonly are sessile-glandular as well as lanate or tomentose; the leaves are petiolate and obovate to rotund with coarsely toothed margins. The phyl- laries often are distinctly foliaceous and even in length, similar to those of Asian “Brachyactis” (see below). The ray corollas are strongly reduced in size, barely exceeding the involucre in most species, and sometimes apically lobed. The ligules are mostly white, but they are yellow in some species, clearly a derived condition. Psychrogeton is particularly distinctive in its disc flowers with short-lobed corollas and sterile ovaries (functionally staminate). The genus has been treated as Hrigeron subg. Conyzastrum (Boiss.) M. Pop. (see Botschantsev 1959), but the flowers and fruits are those of Asterinae. Psychrogeton has received a detailed treatment at generic rank by Grierson (1967). Asian “Brachyactis” The ca. five endemic Asian species (Appendix I) that have been identified as Brachyactis are not congeneric with the typical, primarily American species of Brachyactis (= Symphyotrichum sect. Conyzopsis), as noted in the discussion that follows below. Both groups are characterized by multiseriate, nearly eligulate pistillate flowers and foliaceous phyllaries, these features developed convergently. Gray (1880) and Grierson (1967, 1982) have noted that the southwest Asian and Himalayan species of Brachyactis are similar to Conyza, which is similar in its numerous, highly reduced pistillate flowers. The latter is broadly interpreted in the Old World, but Asian “Brachyactis” differs from Conyza in features of phyllary, achene, and pappus morphology, and I am unaware of any species of Conyza, from the Old or New World, that could be considered congeneric with Asian “Brachyactis.” Nesom: Review of Aster taxonomy 169 In contrast, there is a resemblance suggestive of close relationship between Asian “Brachyactis” and Psychrogeton in their habit, glandular vestiture, ten- dency for foliaceous phyllaries, and flattened, obovate, glandular achenes. Ge- ographically as well, these two groups are similar. Asian “Brachyactis” differs, however, in its fertile central flowers and tendency for heads on axillary pe- duncles. The species of the latter have not been consistently aligned with any other genus, and I agree with Grierson (1982), who has noted that two undescribed genera may be represented among this smali number of species. THE NORTHERN HEMISPHERE SUBTRIBES In a study and classification of the tribe Astereae (Nesom 1994d), the five primarily Northern Hemisphere subtribes are hypothesized to be mono- phyletic and distinct as a group from those of the Southern Hemisphere. The Asterinae and Solidagininae appear to be the least specialized among the es- sentially North American subtribes, and some species in each group are very similar to Hinterhuberinae. The Asterinae are mostly herbaceous (vs. woody), but a number of genera of Solidagininae are similar to Hinterhuberinae in their shrubby habit; both subtribes produce mostly eglandular achenes (vs. commonly glandular in the Hinterhuberinae). Many Solidagininae produce punctate-resinous leaves, a feature commonly found in the Hinterhuberinae. Keeled phyllaries are characteristic of some basal Asterinae as well as the Chrysopsidinae and some Machaerantherinae, but not of the Solidagininae. Some genera of Hinterhuberinae produce keeled phyllaries. Primitive features in at least the apparently basal genera of Asterinae ard Solidagininae (as- suming that the primitive states are found in the Hinterhuberinae) include the following: a corymboid capitulescence; disc corollas with relatively long, coiling-reflexing lobes; papillate (vs. hairy) collecting appendages of the disc style branches; terete, multinerved achenes; and multiseriate pappus of equal- length bristles, these sometimes with dilated apices. The four autochthonous New World subtribes (Asterinae, Solidagininae, Machaerantherinae, and Chrysopsidinae) are characterized by essentially terete, cylindric or fusiform, multinerved, mostly eglandular achenes, while plants of the Old World groups of Asterinae consistently produce flat, obovate, mostly 2-nerved achenes commonly with glandular faces. Outside of the Northern Hemisphere, species of the Hinterhuberinae are most similar to those of the northern groups and it is likely that this subtribe is the closest representative of the ancestral stock from which they arose. Members of the Hinterhuberi- nae produce mostly terete, multinerved achenes, as do those of the tribes that have been hypothesized to be ancestral or near-ancestral to the Astereae (1.e., Anthemideae, Gnaphalieae, and Senecioneae). ‘The primitive ray color for the Northern Hemisphere subtribes is not clear, although there is reason to suspect that the primarily yellow-rayed Chrysop- 170 PHYTOLOGIA volume 77(3):141-297 September 1994 sidinae and Machaerantherinae both may have been derived from white-rayed ancestors (see below). Genera of the Hinterhuberinae are divided in ray color (some with white, others with yellow rays). Basal Solidagininae (particularly Solidago and Oligoneuron) differ from the Asterinae primarily in their yellow rays, although white-rayed species occur in both of these genera as well as others of the subtribe. Tonestus, in which ray color varies between white and yellow, is questionably included in the Asterinae; the genus would be the only one in the Asterinae with yellow-rayed species. The Solidagininae is less rigidly fixed in its ray color, as white-flowered species and genera occur sporadically throughout the tribe (Nesom 1993c). In some phylogenetically basal Solidagininae (Solidago and Oligoneuron), the white-rayed species also produce pappus bristles with dilated apices. The correspondence of these features is so striking and so similar to basal elements of the Asterinae that it seems plausible their appearance results from the expression (perhaps derepression) of a barely ancestral set of linked genes. White-rayed taxa (but without apically dilated pappus- bristles) also occupy basal or near-basal positions in the Chrysopsidinae (i.e., Noticastrum; Nesom 1991b) and in the Machaerantherinae (Xylorhiza; Morgan & Simpson 1992). The Solidagininae appears to be a relatively loose association of several gen- era and distinct generic groups (Nesom 1993c, 1994e). I previously suggested that Doellingeria and Sericocarpus are members of the Solidagininae (Nesom 1993c), but they are placed here in the Asterinae; the placement of Tonestus is still equivocal. The seemingly small differences that suggest placement of these genera in one group rather than the other emphasize the putatively close relationship between these subtribes. The subtribes Machaerantherinae and Chrysopsidinae are similar to basal Asterinae in their primitively corymboid capitulescence, carinate phyllaries, terete, multinerved achenes, and multiseriate pappus; they are similar between themselves in their yellow ray flowers and specialized tendency for the produc- tion of large, straight-sided crystals in the disc corollas. The Machaerantheri- nae have a base chromosome number of z=6, taprooted habit, often glandular vestiture, strongly graduated phyllaries commonly with a distinctly delimited, green apical patch, and a multiseriate pappus of stiff bristles markedly uneven in length; the collecting appendages of the disc style branches of primitive groups are papillate and relatively short. The Chrysopsidinae have a base chromosome number of z=9, phyllaries more evenly pigmented and strongly carinate, and a multiseriate pappus with the outer series usually distinctly shorter than the inner; the disc collecting appendages are long and hairy even in the primitive groups. These two subtribes apparently are restricted to the New World (Nesom 1994e), with several possible exceptions (see previous dis- cussion of Asterinae). Further evidence for their apparent common ancestry with the Solidagininae and Asterinae is provided by molecular data (Suh 1989; Morgan 1990; Suh & Simpson 1991; Morgan & Simpson 1993). With their mix Nesom: Review of Aster taxonomy 171 of primitive and specialized features, however, the segregation of neither the Machaerantherinae nor the Chrysopsidinae appears to create paraphyly within any other group of Astereae. Eucephalus and Ionactis, as discussed below, show morphological similar- ities to both the Chrysopsidinae and Asterinae, which may provide a focal point in the investigation of relationships among these subtribes (Figure 2). Similarly, some species of Symphyotrichum show apparently parallel morpho- logical resemblance to some Machaerantherinae, and artificial hybrids have been constructed between taxa of Symphyotrichum and Machaeranthera (see Nesom 1994f). THE AMERICAN GENERA Recognition that the ca. 181 primarily New World species of Asterinae are distinct as a group from Aster and the thirteen other primarily Old World genera that are its closest relatives also suggests that the New World species should be accorded corresponding nomenclatural status. There appear to be two broad options for meeting this requirement. (1) All New World species previously treated as Aster could be maintained within a single genus, for which the oldest available generic name is Eurybia (Cass.) S.F. Gray (from 1821, see comments below). The next oldest names, Doellingeria, Sericocarpus, and Symphyotrichum, were all published by Nees in 1832. The first two of these have a long tradition as separate genera and have recently been accepted as such (Nesom 1993b, 1993f, and the present treatment); the third, Symphyotrichum (Aster novi-belgii L., the type), is ap- plicable in the strict sense to a group of about eleven species placed by Jones (1980a) within Aster subg. Symphyotrichum sect. Salicifolit, although these species clearly are congeneric with a broader group that totals ca. 77 species (see Appendix II, Symphyotrichum subg. Symphyotrichum, as treated here). As noted in the introduction of the present paper, the congeneric treatment of the even larger, diverse group of 180 species of American Asterinae apparently would require the addition of Psilactis, and perhaps Tonestus, to complete an otherwise paraphyletic group. (2) The New World species could be partitioned into smaller genera that appear to correspond with patterns of phylogeny and morphological variation. Some of these groups of Asterinae have been established as separate genera, at least in their basic concept, for a long period. And notwithstanding recent heterogeneous concepts, even a botanist as deeply immersed in the study of North American Aster as Lloyd Shinners suggested that A. linarifoltus L., A. acuminatus Michx., and A. umbellatus Mill., among West Virginian species (1945), would be better treated within segregate genera. The segregates /on- actis, Heleastrum, and Doellingeria were recognized relatively recently in the treatment of Texas Asteraceae (Correll & Johnston 1970). 172 PHRYTOLCO€eTA volume 77(3):141-297 September 1994 Ampelaster Oreostemma Eurybia Sericocarpus Aster & Asian Asterinae Oclemena ' Asian “Brachyactis" ser. Albescentes Aster tataricus Eucephalus ? " Boltonia Chloracantha Figure 1. Phyletic arrangement of the genera of the “Eurybian lineage” in relation to other genera and generic level groups of Asterinae. See discussion in text. Nesom: Review of Aster taxonomy x * it tl Nn ral a) pas il en) OR n = cS = ~~ c Cs ga * < il = Nn wn =e Q) - Sc hans e : G ne n * u — Ww = & "i N x [ om | = * i oo = — Ww —— n c cs aa = * u fl a oo * = @) ft — =| A x a a ne ee Q — 2 Z — * il oo ==. Malis N —" J Figure 2. Diagramatic representation of the two subgenera and twelve sections of the genus Symphyotrichum. The base chromosome number and the number of species (in square brackets) are shown for each section. Natural hybrids occur between the sections connected by double-pointed arrows. See discussion in text. 173 174 PHYTOLOGIA volume 77(3):141-297 September 1994 I have followed the second option, accommodating the New World species of Aster’s. lat. within twelve pre-existing genera, adding two newly described, monotypic ones to account for the pattern of variation. The genera accepted in the present treatment appear to be monophyletic, with the few caveats provided in the following discussions of individual groups, and for the most part each is sharply bounded and easy to recognize. More than half of the American species are placed in Symphyotrichum; this genus comprises two relatively distinct subgenera (in the present treatment), incorporating the group recently segregated as Virgulus. Phylogenetic hypotheses for the American genera of Asterinae (Figure 1, although relatively unresolved) and for the subgenera and sections within Sym- phyotrichum (Figure 2) are provided in the present study, but details of the cladistic relationships among the taxa are equivocal. Additional comments are provided below under “The Eurybian lineage.” The major features and infras- tructure of these genera and considerations in their delimitation are discussed below. I. Doellingerta Eleven species have recently been consolidated as the genus Doellingeria (Nesom 1993f) and placed in two sections, primarily based on differences in leaf morphology: sect. Doellingeria has lanceolate, epetiolate, and mostly en- tire leaves, while sect. Cordifolium has cordate, petiolate, and serrate leaves. The three species of eastern North America are sect. Doellingerza; two of the eastern Asian species are sect. Doellingeria, the others sect. Cordifolium. The genus is briefly characterized as follows: perennial herbs, eglandular, glabrous to sparsely strigose; heads in a corymboid capitulescence; phyllaries in 2-4 graduate series, broad, apically rounded, with a raised midvein (but not keeled) and often several lateral veins, without a herbaceous apical patch; rays white, few, not coiling; disc corollas abruptly ampliate, with deeply cut, reflexing- coiling lobes; achenes eglandular, terete with 5-9 raised, often resinous veins, elongating to 3-4 mm long at maturity; pappus 2-3 seriate, the bristles with dilated apices; base chromosome number, z=9. Doellingeria was earlier placed within the Solidagininae (Nesom 1993f), emphasizing its similarities to Solidago and Oligoneuron. Its phyletic position is somewhat equivocal, but it is here positioned within the Asterinae, em- phasizing the white rays and distinctly 3-seriate pappus (with a shorter outer series) that it shares with Oclemena, Eucephalus, and Jonactis. Nesom: Review of Aster taxonomy 175 II. Oclemena Oclemena is a North American group first recognized as a discrete phylad and segregated at generic rank by Greene (1903), who included O. (Aster) acuminata (Michx.) E. Greene and O. (Aster) nemoralis (Aiton) E. Greene in the genus. Nuttall (1840) also early recognized the distinctiveness of O. nemoralis by placing it as the type and only species of his Galatella sect. Calianthus. One additional species, O. (Aster) reticulata (Pursh) Nesom, is added to the group in the present treatment. Plants of Oclemena are briefly characterized as follows: cauline leaves di- minished in size toward the stem base, the lowermost reduced to scale-like bracts; leaf surfaces sessile-glandular, each gland producing a clear, orange- resinous head; stems densely invested with long, loose hairs with colored cross- walls; capitulescence corymboid, the heads on long, naked peduncles; phyllar- ies in 3-4 series graduated in length, narrowly oblong-lanceolate to linear- lanceolate with acute apices, evenly thin-herbaceous or scarious (without an indurated basal portion), essentially flat but the midvein often raised and then the phyllaries slightly but distinctly keeled; disc corollas pink or reddish at anthesis, with deltate, erect lobes; collecting appendages of the disc style branches narrowly lanceolate and papillate at least on the distal half; achenes fusiform to narrowly oblong in outline, plump though often evidently flattened, with 5-8 evenly spaced, longitudinal nerves, the entire surface moderately to densely invested with resinous glands, and the achene base markedly stipitate; and pappus multiseriate, with 2-3 inner series of long, barbellate bristles, with an outer series of much shorter setae in O. acuminata ard O. reticulata. The chromosome number of all species is n=9 (e.g., Hill & Rogers 1970), and the morphology of the NOR chromosome is the primitive type (sensu Semple et al. 1983). Greene’s recognition of Oclemena (1903) was prompted by his field ob- servation that the heads (in bud) of O. acuminata are nodding. The same behavior has been confirmed for O. nemoralis (L. Brouillet pers. comm.) and Burgess (1903, p. 1227) also observed it in O. acuminata: “Remarkable for its soft-pubescent limp subviscid leaves and its decurved buds becoming erect and fragrant in flower.” Greene (p. 4) also noted that O. acuminata “propagates by tubers rather than by stolons. At the end of each long slender subterrane- ous branch a small organ is formed which, exactly resembles a small potato, and from each of these springs a plant for the next year.” The other taxa also produce swollen rhizome tips (not so abruptly swollen as a “small potato”), a feature more easily preserved and observed from herbarium specimens than the orientation of buds. The three species of Oclemena can be identified by the following contrasts: 1. Leaves broadly obovate, relatively thin, lower surfaces sessile-glandular or apparently eglandular, the margins coarsely serrate, not revolute; cool 176 PHY TOL@MCIA volume 77(3):141-297 September 1994 forests, Appalachian Mts. from Georgia and North Carolina northward to the eastern Great Lakes area, Ontario, Québec, Nova Scotia, and Newfoundlandosicceas 24 $27). can oad Ak SS O. acuminata 1. Leaves narrowly to broadly elliptic, coriaceous, lower surfaces prominently sessile-glandular, the margins entire or slightly serrate distally, distinctly TOOL UN ods os. ciasis acpaniore ae aids win eosin Ai gl Shae < BS gan ae (2) 2. Peduncles eglandular, hairs with colored crosswalls absent or rare; achenes glandular, without other hairs; rays 10-17; pappus 2-seriate; boggy habitats, from New Jersey northward and westward to On- tario, Québec, Nova Scotia, and Newfoundland. .... O. nemoralis 2. Peduncles glandular, heavily invested with hairs with colored cross- walls; achenes glandular and conspicuously hairy; rays (5-)7-11 (- 14); pappus 3-seriate, the inner of 2 series of bristles of equal length, the outer shorter; dry, woodland habitats in Florida and South Car- clita. wiwichie. lt Bad. ix? Sine aess. Aosta O. reticulata Oclemena reticulata and O. nemoralis are similar in overall appearance, but O. reticulata and O. acuminata are similar in their biseriate inner pappus and dense vestiture of long hairs with colored crosswalls. Oclemena acuminata and O. nemoralis have a more northern distribution and occur in montane and moist habitats (see Brouillet & Simon 1981). Oclemena reticulata is similar to Doellingeria in its relatively few rays, long disc corolla lobes, 3-seriate pap- pus, and pappus bristles with clavate apices, but such features apparently are primitive in the lineage from which Oclemena and Doellingeria have arisen. The observation that Oclemena x blake: (Porter) Nesom originates as a fer- tile, recurrent hybrid between O. acuminata and O. nemoralis has been made by numerous botanists (see Pike 1970), and this has subsequently been cor- roborated in detail (Pike 1970; Hill & Rogers 1970, 1973; Hill 1976). Detailed information regarding the distribution and biology of the parental species is provided by Brouillet & Simon (1981). Oclemena reticulata (as Aster) was treated within sect. Triplopappus of Aster subg. Doellingeria by Jones (1980), Semple & Brouillet (1980), and Semple et al. (1991) rather than with its closer relatives (as placed here), but Semple et al. (1991) recognized that O. reticulata was set apart from the three species of Doellingeria treated by them. The tradition for the separate classification of O. reticulata was established by Torrey & Gray (1841), who included the species (as one of its synonyms, Diplopappus obovatus {Nutt.| Torr. & Gray) in Diplopappus subg. Triplopappus along with other species now identified within the genus Doellingeria (Nesom 1993f). Torrey & Gray included A. reticulatus Pursh among species of Aster hardly known to them and even speculated that it might belong to some other genus than Aster. In Nesom: Review of Aster taxonomy 177 their Aster subg. Orthomerts, Torrey & Gray included two species of Oclemena (as A. acuminatus and A. nemoralis Aiton) as well as one species presently treated in the genus Xylorhiza, two in Eucephalus, and Aster ptarmicoides (Nees) Torr. & Gray (= Oligoneuron album [Nutt.] Nesom). Their discussion of the relationships of subg. Orthomeris is the most reasonable if subg. Or- thomeris is lectotypified by A. acuminatus (see Appendix II), and Aster subg. Orthomeris sensu stricto becomes equivalent to Oclemena. Various Old World taxonomists have used “sect. Orthomeris” in a broad sense for certain Asian species of Aster. Kitamura (1936) placed A. glehnii Fr. Schmidt and A. dimorphophyllus Franch. & Sav. within ser. Orthomeris and formally described several other series within a broader (sect.] Orthome- ris. Aster glehni does closely resemble Oclemena (comments below), but A. dimorphophyllus has most recently been treated as a species of Doellingeria (Nesom 1993f). Kitamura separated [sect.] Orthomeris from typical Aster (sect. Aster) in 1936 but the next year (1937, p. 328) noted that “In Eastern Asia, Euaster and Orthomeris are not so distinct as in North America” and included [ser.] Orthomeris in a much larger, heterogeneous group. Aster “sect. Orthomeris” was also used by Grierson (1964) to circumscribe a group of Asian species, including A. albescens, A. trinervius, A. ageratoides, and others. Of these, A. glehnit, A. trinervius, and A. ageratoides, in partic- ular, resemble Oclemena in their flexuose stems, loosely corymboid capitules- cence, resinous-glandular leaves with toothed margins, and glandular achenes. In these species, however, the achenes are non-stipitate, obovate, and dis- tinctly flat with two lateral nerves (or the ray achenes sometimes with an extra nerve on one or both faces), the pappus is generally 1-seriate, the disc corollas are abruptly ampliate above the tube, with lanceolate, deeply cut, reflexing-coiling lobes, the style branches have shorter, closely papillate col- lecting appendages, and the phyllaries are somewhat variable in morphology but unkeeled. In a broader view, this latter set of features, especially the achene and style branch morphology, are characteristic of most of true (typi- cal) Aster, and sessile-glandular leaves also occur in many species. A sample of other relatively well-known Asian species that appear to be closely related to A. glehniu, A. trinervius, and A. ageratotdes are A. baccharoides Steetz, A. lasiocladus Hayata, A. philippinensis Moore, and A. vestitus Franch. (and others, see Appendix I, Aster sect. Ageratoides). A combination of other features of Oclemena, in contrast, suggest that it is more closely related to North American taxa, especially to Doellingeria, than to Old World species of Aster. The most significant of these features (vs. typical Aster) are its subterete, narrowly oblong-fusiform, multinerved achenes (vs. flat, obovate achenes with two, distinctly marginal nerves, some- times 1-2 others on the faces), pappus bristles (in O. reticulata) with dilated apices (vs. attenuate bristle apices), and disc corollas often pinkish or pur- plish at anthesis (vs. remaining yellowish). Phyllaries strongly graduated in 178 PHYTOLOGIA volume 77(3):141-297 September 1994 length and a multiseriate pappus occur both in Doellingeria and in typical Aster. The NOR chromosome morphology of Oclemena is similar to that of Doellingeria, Eucephalus, and Sericocarpus (Semple et al. 1983), but the Old World species of Aster (primarily sect. Ageratoides) to which Oclemena is most similar morphologically have different NOR morphology (see discussion below, under “Chromosome evolution in the Astereae”). Oclemena differs from Doellingeria in a number of features, eight of which were noted and scored by Jones & Young (1982); two of the most significant features of Oclemena, however, glandular leaves and achenes, were not included in their scoring. Differences between the two genera are summarized in the following couplet. ~ Key to Oclemena and Doellingeria A. Buds and young heads nodding; phyllaries linear-lanceolate with acute apices, l-nerved, usually with a low keel, the outer not basally indurated; disc corolla lobes deltate, mostly erect; mature achenes fusiform to nar- rowly oblong in outline, usually somewhat compressed at maturity, api- cally attenuate, with 5-8, slightly raised, non-resinous nerves, the achenes surface with a vestiture of sessile glands; achenes not lengthening to the full height of the involucre; pappus bristles sometirnes slightly dilated in O. reticulata but apically attenuate in the other texa. ...... -Oclemena A. Buds and heads erect; phyllaries with rounded apices, usually with dis- tinct lateral nerves, not keeled, the outer somewhat basally indurated; disc corolla lobes lanceolate, spreading-reflexing; raature achenes some- what obovate in outline, mostly terete at maturity, apically shouldered, with 4-8 longitudinal, strongly raised, orange-resinous nerves, glabrous to strigose, eglandular; achenes elongating to the iull height of the in- volucre; pappus bristles prominently apically dilated. ..... Doellingeria In summary, there is evidence to consider Oclemena a monophyletic, North American endemic more closely related to Doellingeria and other North Amer- ican groups as to species of Old World Aster. Of the North American groups hypothesized to be closely related to elements of Old World Aster (particularly sect. Ageratoides), however, Oclemena appears to be among the most similar to them, and the parallel development of Oclemena (as hypothesized here) probably is indicative of common ancestry not far removed. The nomencla- ture within Oclemena is already available for two species, and a third species is added here, along with the commonly recognized and formally named inter- specific hybrid O. x blakez. Nesom: Review of Aster taxonomy 179 III. Eucephalus Eucephalus has long been recognized as a separate genus and most of the required nomenclature for its segregation already exists. The species are distributed primarily in California and nearby areas of northwestern United States and adjacent Canada. It is a remarkably coherent group in morphol- ogy, recognized particularly by its scale-like lower cauline leaves, corymboid capitulescence, broad, strongly keeled phyllaries without a sharply delimited apical patch, flattened, obovate, eglandular achenes, and multiseriate pappus of apically dilated bristles. Eucephalus is briefly characterized as follows: perennials usually from creep- ing rhizome, sometimes tap-rooted in E. paucicapitatus (B. Rob.) E. Greene; glabrous or sparsely pilose with thin-based hairs to closely tomentose, granular- glandular or minutely sessile-glandular in E. gormani Piper, E. pauctcapitatus, and E. glabratus (E. Greene) E. Greene (under the heads); stems mostly sim- ple or few-branched until the capitulescence, arising directly from the rhizome without an evident caudex; leaves all cauline, scale-like on the basal portions of the stems, large and relatively even-sized and evenly arranged above, sessile, not clasping (or slightly subclasping), entire, sometimes 3-nerved, the sec- ondary venation reticulate; heads sometimes reduced to one but mostly 6-20 and corymboid (loosely so or paniculate in E. breweri [A. Gray] Nesom); phyl- laries in 4-6 series strongly graduated in length, ovate, often convex, distinctly keeled from base to tip, stramineous-indurate, relatively even textured, the margins (inner series) thin-hyaline, often purplish distally, without a distinctly delimited apical patch but the apical area sometimes green; disc corollas yel- low, usually remaining yellow, tubular, the tube ca. 1/3 the corolla length, the lobes deltate and erect to triangular and reflexing; disc corolla style branches with collecting appendages lanceolate to linear, mostly papillate above the base (hairy in some species); rays white to bluish, slightly coiling; achenes obovate, not basally stipitate, strongly flattened with a pair of lateral nerves, 2-nerved (e.g., E. ledophyllus [A. Gray] E. Greene and E£. engelmannii [D.C. Eat.)] E. Greene), in other species commonly with 1-2 additional nerves on each face, eglandular; carpopodium symmetrical, orthogonal; pappus of terete bristles usually dilated at the apex, in 2-3 series, all of equal length or the outer sometimes markedly shorter; base chromosome number, z=9, the NOR chromosome morphology of the primitive type (fide Semple et al. 1983). The rayless Californian species Eucephalus brewert was transferred from Heterotheca and correctly placed by Semple (1988) among the species of Eu- cephalus (as a subgenus of Aster). The discoid condition also occurs in £. vialis Bradshaw, E. brickellioides (E. Greene) Nesom, and EL. glabratus, al- though the latter two species may sometimes produce 1-5 ray flowers. The earlier treatment of EF. breweri within both Chrysopsis and Heterotheca and its long taxonomic persistence there reflects its remarkable resemblance to 180 PEY TO LO-CTA volume 77(3):141-297 September 1994 plants of the Chrysopsidinae, much as Nesom & Leary (1992) earlier observed a strong similarity between Jonactis and the Chrysopsidinae. If the flattening and apparent reduction in venation in Fucephalus achenes is homologous with that of Asian Asterinae, it suggests that the former may occupy an ancestral position with respect to the latter. This is especially plau- sible in view of other similarities between them. The achenes of Canadanthus (C. modestus {Lindl.| Nesom) are distinctly flattened and oblanceolate, but they are multinervate and the flattening appears to be a more evident spe- cialization within its lineage, where its closest relatives have mostly cylindric achenes. The flattened, few-nerved achenes of Symphyotrichum also are clearly specialized. Jonactis produces somewhat flattened achenes with reduced ve- nation, but the nature of its relationship to other genera is more obscure. The species of Eucephalus resemble some species of Old World Aster, par- ticularly those of sect. Ageratozdes, in their relatively tall stature, leafy habit, and flattened, obovate achenes. Eucephalus differs from Old World Aster, however, in a combination of features: keeled phyllaries, disc corollas not abruptly ampliate, greatly elongated collecting appendages of the disc style branches, eglandular achenes, “triseriate” pappus (with a shorter outer series) of apically dilated pappus bristles, and chromosome morphology. Instead, Eu- cephalus appears to be closer to other North American groups in this same set of characters, although some of them appear to be plesiomorphic similarities. IV. Jonactis Tonactis is primarily a genus of the western United States (with four species in that region), but the most widespread species (J. linaritfolia {L.] E. Greene) is restricted the eastern North America (Nesom & Leary 1992; Nesom 1992b). The group has long been recognized as a natural one. Plants of Jonactis are briefly characterized as follows: low perennials from a taproot or thick, woody caudex branches; stems and leaves glandular in /. caelestis Leary & Nesom, the other species eglandular; leaves stiff, congested on the stems (internodes short); heads usually solitary, sometimes 2-3 and loosely corymboid; phyllaries strongly graduated in length, strongly keeled, relatively even textured, without an apical patch; disc corollas narrowly tubular; disc style branches with collecting appendages lanceolate, hairy from base to tip; rays bluish, coiling; achenes narrowly obovate in outline, those of the disc 2(-4)-nerved, of the ray (2-)3-nerved, flattened, not stipitate, glandular in J. stenomeres (A. Gray) E. Greene and J. elegans (Soreng & Spellenb.) Nesom, the disc achenes sterile in /. caelestis; carpopodium oblique; pappus of apically attenuate bristles in 1-2 series of equal length, with a much shorter outer series of bristles or scales; base chromosome number, z=9. The species of Jonactts are particularly similar to Eucephalus and they have been hypothesized to be closely related (Semple & Brouillet 1980a; Jones & Nesom: Review of Aster taxonomy 181 Young 1983). These two genera are similar in their evenly distributed and even-sized (mostly) cauline leaves, strongly graduate, keeled phyllaries with- out an apical patch, few-nerved, relatively flattened achenes, and multiseriate pappus with a short outer series. Eucephalus differs from Jonactis in a number of features: taller stature, rhizomatous base, leaves not congested, stems and leaves without stiff, thick-based hairs, heads usually more numerous and often distinctly corymboid, disc style branches commonly with papillate collecting appendages, achenes more distinctly flattened and more broadly obovate, car- popodia symmetrical, and pappus bristles apically dilated. In most of these features, Jonactis is the more specialized. The hypothesized phyletic alliance of Jonactis with the Chrysopsidinae (Nesom & Leary 1992, Nesom 1991b) emphasized their common production of carinate phyllaries without an apical patch, linear-lanceolate and hairy collect- ing appendages, oblique carpopodia, strongly shortened outer pappus series, and (in one species) glandular cauline vestiture. Plants of Jonactis, however, lack the large, straight-sided crystals in the disc corollas that are character- istic of the Chrysopsidinae, the rays are bluish to white rather than yellow, and the achenes have fewer nerves than in the goldenasters, except for Het- erotheca, where the reduction in nervation is interpreted as a specialization within the subtribe. Similar features of pappus, phyllaries, and vestiture can also be found among species of Hucephalus, as noted above, but Jonactis is very different from Eucephalus in its habit and small, rigid, congested leaves with stiffly ciliate margins. Jonactis is regarded here as a relatively isolated genus, perhaps close to Eucephalus or perhaps more distantly separated from the Asterinaean lineage. Plants of Jonactis are similar in habit and overall appearance to those of the Asian genus Arctogeron, but the latter produce papillate collecting appendages and broadly obovate achenes and can be considered securely placed among Asian Asterinae. THE EURYBIAN LINEAGE The Eurybian lineage includes nine genera (Figure 1), from Sericocarpus to Symphyotrichum. The major groups of the lineage are generally character- ized by phyllaries in 3-5 series strongly graduated in length and with a green, distinctly demarcated apical patch. Mostly herbaceous, equal-length phyllar- ies are characteristic of Oreostemma, Psilactis, Almutaster, Canadanthus, and a similar tendency also occurs in some species within Eurybia, subg. Virgu- lus, and subg. Symphyotrichum, but this is interpreted here as specialization within the lineage. Species of Aster sect. Aster produce a sharply delimited apical patch similar to that in Sericocarpus and Eurybia; some taxa of the Machaerantherinae and Solidagininae also produce an apical patch, and the 182 PHYTO DMG Ya volume 77(3):141-297 September 1994 similar morphology in these taxa appears to have developed in parallel to that of the Eurybian lineage. Sericocarpus is the most primitive genus of the Eurybian lineage, retain- ing a set of unspecialized features: sessile-glandular vestiture (vs. stipitate- glandular), the capitulescence generally a corymboid cyme (the tendency to produce glomerated heads is specialized), disc corollas distinctly widened in the throat and limb, with long, reflexing-coiling lobes and remaining white or creamy at maturity, disc style branches with short, papillate collecting ap- pendages, ligules essentially non-coiling, and pappus 2-3 seriate, the bristles with dilated apices. The remaining, more specialized genera of the Eurybian lineage are char- acterized as follows: disc corollas narrowly tubular with short, erect lobes (abruptly ampliate distally in some of the primitive species of Eurybia and subg. Symphyotrichum), at least the apex usually becoming distinctly reddish or purplish at maturity; disc style branches with linear-triangular collecting appendages spreading-hairy from base to tip (rarely papillate in some species of Eurybia); and ray flowers with coiling, blue or purple ligules (less commonly white, not strongly coiling in some Eurybia). The five most specialized genera, the Symphyotrichum subgroup (Figure 1), have consistently shortened achenes compared to the longer, narrowly cylindric ones of Eurybia, Oreostemma, and Ampelaster, although the posi- tion of the latter is somewhat equivocal on the basis of other characters. The Symphyotrichum subgroup, including Ampelaster, have a 1-seriate pappus of bristles consistently attenuate at the apex and an open, variably paniculate capitulescence (compared to the distinctly corymboid cymes of Eurybia and Sericocarpus and most of the other putatively primitive genera of the sub- tribe; the homology of the highly reduced capitulescence »f Oreostemma is not evident). Further, all of the Asterinaean species with chromosome numbers reduced from z=9 are members of the Symphyotrichum subgroup, and all of this subgroup except Almutaster have cauline leaves with clasping bases, at least in the putatively primitive species. The unity of the Eurybian lineage is further emphasized by morphologi- cal similarities (homologous and parallel) among the genera. This is reflected in Cronquist’s observation (1955, p. 71) that the “characters of the various groups [of North American Aster] interlock most confusingly.” Although par- allelisms suggest that these groups are closely interrelated, natural groups among the American asters can be seen as much more discrete as a result of relatively recent studies, including the present one. Distinctive and genetically isolated groups of the Eurybian lineage have already been treated as separate genera (Psilactis, Oreostemma, Almutaster, Virgulus). If the whole Eurybian lineage were considered a single genus, such 2 group would be unparalleled in the tribe (Nesom 1994e) in its composition of highly distinctive, discrete, and genetically isolated subgroups. Other North American generic segregates Nesom: Review of Aster taxonomy 183 from Aster recognized in the present treatment (e.g., Doellingeria, Oclemena, Ionactis, Eucephalus) are simple to recognize and correspondingly distinct in phylogeny (outside of the Eurybian lineage). V. Sericocarpus Sertcocarpus comprises five species, three in the eastern United States and two in the western U.S. A taxonomic summary and discussion of its main features and relationships was recently presented (Nesom 1993b). It is briefly characterized as follows: perennial herbs from woody roots, sometimes short- rhizomatous; leaves sessile- or punctate-glandular; heads sessile or subsessile in glomerate clusters; phyllaries keeled, with a sharply delimited, basally trun- cate, green apical patch, strongly indurate-thickened and convex below; disc corollas white, not purplish at maturity, funnelform, hardly abruptly ampli- ate; style branch appendages papillate; rays white, not coiling; achenes nar- towly obconic to nearly cylindric, not basally stipitate, multinerved, strigose- sericeous; pappus in 2-3 series of equal length, the bristles apically dilated; base chromosome number, z=9. The morphology of the NOR chromosome is the primitive type (sensu Semple et al. 1983). Sericocarpus has long been recognized as a distinct genus, and it was the most recent addition to North American Aster (Cronquist 1947b). As noted in the Introduction to this paper, and in contrast to my earlier view (1993b), I ac- knowledge that Cronquist as well as Semple & Brouillet were correct in placing Sericocarpus close to other species of North American asters. In the present treatment, Sertcocarpus is regarded as closely related to Eurybia, although the similarities between them apparently are mostly plesiomorphic. The similar- ities between Sericocarpus and the Solidagininae, which I emphasized earlier, are here interpreted as parallel rather than homologous. In this view, however, this remarkable set of parallelisms indicates a recency of common ancestry, and the apparent phyletic proximity of the Asterinae and Solidagininae is noted elsewhere in the present discussion. The resemblance between the Solidagininae and Sericocarpus and the cor- responding distinction of the latter from Eurybia support the recognition of Sericocarpus at generic rank. Details of the morphological distinction between Sericocarpus and Eurybia are provided under the latter (in the following dis- cussion). VI. Eurybia This genus has been consolidated primarily from a number of groups pre- viously recognized by a variety of names: Biotia, Heleastrum, Herrickia, We- beraster, Aster sect. Radulini, and Aster sects. Calliastrum and Spectabiles. 184 Puy TOLTGCGTIA volume 77(3):141-297 September 1994 The 28 species are divided into nine sections (in two subgenera) and recog- nized bya generic name that has not generally been applied to North American species. A. Usage of the name Eurybia The oldest generic name potentially applicable to any North American seg- regate from Aster s. lat. is Hurybia (Cass.) S.F. Gray (see below), based on Aster subg. Eurybia Cass., a combination at generic rank that has previously been attributed to Cassini. The name Eurybia has been applied in a limited sense to species of the North American Aster subg. Biotia DC. ez Torr. & Gray (sensu Jones 1980a; also see Lamboy & Jones 1987b). The name Biotia DC. (1836) at generic rank for this group is a heterotypic, later homonym of Biotia Cass. (1825) and use of de Candolle’s name is illegitimate in reference to a genus. Hurybia has generally been regarded as a synonym of Olearia (e.g., Bentham 1866), a genus of Australia and New Zealand, but there apparently has been no pointed discussion regarding the typification and definition of Eu- rybia. Index Nominum Genericorum (Farr et al. 1979) and Australian Plant Names Index (Chapman 1991) both noted that a type for it has not been des- ignated. Two problems are considered in the following discussion. When and by whom was the legitimate combination at generic rank made for Eurybia? And how is the name to be typified and interpreted, in view of considerable ambiguity in its early application? a. Cassini’s establishment of Eurybia In the original description of Eurybia (as Aster subg. Eurybia Cass., Bull. Sci. Soc. Philom. Paris 1818:166. 1818.), Cassini placed three species within this taxon, without specifying any one of them as the type: A. chrysocomoides (Desf.) Desf., A. tripolium L., and A. corymbosus Sol. ez Aiton. Only the third of these is a North American species; it is a member of the Biotia group. Cassini provided no specific comment regarding the derivation of the name Eurybia, but the Greek adjective “eurys” connotes “broad, wide, or widespread,” while “baios” connotes “little, scanty, or few.” It seems reasonable to speculate that Eurybia refers to the species treated here within sect. Eurybia, which pro- duce relatively few ray flowers with little-coiling (thus wide-spreading) ligules. In 1820, Cassini provided a review of the main features of his three “sous- genres” of Aster (Dict. Sci. Nat. 16:46. 1820.), which had received a more cursory treatment in 1818, but he did not include any of the three, originally cited species of subg. Furybia in the discussion. Instead, he included only four Australian species now placed within Olearia, although it is not clear that he intended to limit the genus to those four. Further, Cassini began Nesom: Review of Aster taxonomy 185 the first sentence of the 1820 discussion with “This new genus of plants,” but following that, he repeatedly referred to the group as a subgenus. Because of this ambiguity, it cannot be clearly established that Eurybia was validated at generic rank in 1820. In his 1820 discussion, Cassini apparently began setting up new nomen- clature for Furybia as a genus, drawing in four, previously named Australian species (Dict. 16:47-48). For two of these names, he took the original epithet into Eurybta; for the other two, he substituted a new epithet that may have seemed more appropriate to him than the original for the plants involved (the substituted epithets match his chosen colloquial names). But because of the ambiguity of rank for Eurybia in 1820 and the corresponding interpretation regarding its validity as a genus, all four of Cassini’s new combinations or new names in Eurybia must be regarded as invalid under any circumstance. Ei- ther (1) they were offered only as provisional names, anticipating the formal change to generic rank for his subg. Eurybia, (2) they were intended only as statements of taxonomic position of the species within Aster subg. Eurybia, or (3) they were proposed as a system of alternative nomenclature equivalent to the existing names in Aster. | Cassini was more definite regarding the status of Eurybia as a genus in yet another taxonomic summary of the group a short time later (Dict. Sct. Nat. 37:486-488. 1825.). In that discussion, he included nine species, including - biotian species as well as Olearta, and made a number of new combinations in Eurybia (including Eurybia corymbosa [Aiton] Cass.). Aster tripolium and A. chrysocomoides were not among these nine, the latter species treated by Cassini in 1825 as the monotypic genus Nolletia Cass. (see below). The 1820 article by Cassini has been considered the date of valid publi- cation for Eurybia as a genus, apparently by Cassini himself (Dict. Sci. Nat. 37:462. 1825.) and by others, e.g., de Candolle (1836), Hooker & Jackson (1895), Farr et al. (1979), and Chapman (1991). Notwithstanding Cassini’s unambiguous treatment in 1825, the elevation in rank of Eurybia must be attributed to the British naturalist S.F. Gray. b. S.F. Gray’s treatment of Eurybia The name Eurybia was used in 1821 by S.F. Gray (Nat. Arrang. Brit. Pl. 2:464-465. 1821.), apparently to provide a name for a circumscription at generic rank; the name was in a coordinate position with others clearly at that rank. As the heading of his entry 232, Gray cited “EURYBIA. Cassine” and the identity of the taxon in reference is unequivocal. Although Gray did not cite a potential basionym or its place of publication by Cassini (or any other publication by Cassini), his reference to “EURYBIA. Cassine” is no more or no less indirect than Cassini’s own treatment of the name and implied new combination in 1825. 186 PHYTOLOGIA volume 77(3):141-297 September 1994 Because Gray did not specifically associate his own name with Eurybia at generic rank, it is not clear that it was his intention to validate the name by making a new combination. It is clear, however, that Gray intended to use the name Eurybia at generic rank, whether or not he considered the name already available (see comments above regarding Cassini’s problematic 1820 discussion) and that he intended to provide a name for one of Cassini’s original three species included within Eurybia. Thus, regardless of his intentions, the name Eurybia at generic rank can be legitimately attributed to S.F. Gray in 1821 as “(Cass.) S.F. Gray.” Gray applied the name Eurybia to only a single species, Aster tripolum L. (and cited the name among the synonyms), but he coined for it the new name “Eurybia maritima,” apparently drawing from one of the polynomials he cited in synonymy: “Aster maritimus coeruleus Tripolium dictus, Raz Syn. 175, 2.” Lamarck validly published Aster maritimus Lam. (a synonym of A. tripolium) in 1789, but Lamarck’s name was not cited by Gray. Thus “Eurybia maritima S.F. Gray” apparently should be taken as superfluous (as seems to be the interpretation in Inder Kewensis), not a legitimate combination at specific rank. In Gray’s comments, it was not “clearly indicated by direct citation in- cluding the term ‘type’ or an equivalent” (as required tae JCBN, Article 8.3) that Eurybia maritima (= Aster tripolium) was to be considered the lectotype of Eurybia. Nor did Gray cite or specifically exclude the other two species (potential types) originally included by Cassini in Aster subg. Eurybia. Thus, while Furybia (Cass.) S.F. Gray can be accepted as a valid name, the basis for typification of Eurybia was not established by Gray, and the possibility was left open that other species might also be included within Eurybia as a genus. c. Nees’s treatment of Eurybia Nees (1832) included in the genus “Eurybia Cass.” five taxa of North American biotians as well as three Australian taxa (all three of the latter now regarded as Olearia). In introductory comments to his treatment of Aster (p. 21), he noted that Eurybia in the strict sense should include only the American species, and in the taxonomic section he separated the biotian species as sub- group “Genuinae.” He did not formally recognize a lectotype for Eurybia, but he concurrently transferred Aster tripolium into a separate genus (see below) and was aware that Cassini (1825), who he followed (see below), similarly seg- regated A. chrysocomoides, leaving only Aster corymbosus within Eurybia (of its three original species). W.J. Hooker (Fl. Bor.-Amer. 2:14. 1840.) followed Nees in identifying the biotian species as Eurybia, although Hooker noted that there appeared to be insufficient basis to warrant their separation from Aster. Nesom: Review of Aster taxonomy 187 d. Eurybia of de Candolle and others De Candolle (Prodr. 5:264-271. 1836.) distinguished the biotian species and the associated Australian species as two genera (Bzotza DC. and Eurybza, respectively), without commenting on the difference between his nomenclat- ural interpretation and that of Nees. He listed “Eurybia Cass. genuina” and “Furybiae genuinae Nees” as synonyms of his Biotza, while crediting Cassini with the authorship of Eurybia (“Eurybia Cass. bull. philom. 188. p. 166. dict. 16. p. 486” — the last “486” apparently a misprint for the page “46” of Cassini’s 1820 article). De Candolle accepted Aster chrysocomordes as the monotypic genus Nolletia (sensu Cassini & Lessing), and he treated Aster tripolium as a monotypic section within the genus Tripolium Nees. Roughly since the time of de Candolle’s influential treatment, Hurybia has generally been associated with Australian species, accumulating many species in the 1850’s primarily from the work of J.D. Hooker and F. Mueller, although it was subsequently subsumed as a synonym of Olearia. Burgess (1906, p. 61) noted specifically that “Cassini’s Eurybia was originally meant for the Tasmanian group of shrubby species which de Candolle retained in it.” e. Lectotypification of Eurybia Notwithstanding Cassini’s apparent inconsistency in the definition of Eu- rybta past its original circumscription, some ambiguity regarding the date and place of publication of Eurybia as a genus, and the current taxonomic equilib- rium regarding its position as a synonym of Olearza, the correct application of the name must be directed by a lectotypification drawn from the three species originally included within Aster subg. Eurybta. Cassini’s brief descrip- tion of this taxon (1818, loc. cit., p. 166, quoted here in full) does not allow an unequivocal selection of a type: “Ce sous-genre de |’Aster comprend les especes de ce genre qui ont la couronne feminiflore comme les vrais Aster et le pericline de squames appliquees comme les Galatea; tels sont les A. chrysoco- modes, tripolum, corymbosus, etc. Le sous-genre comprenant les vrais Aster se distingue des deux autres par la couronne feminiflore, et le pericline de squames inappliquees, appendiciformes; tels sont les A. novt-belgit, longzfolius, amplezicaulis, etc.” There are three choices for the type of Eurybiza. 1. Aster (Conyza) chrysocomoides (Desf.) Desf. This species is the type of Nolletia Cass. (Dict. Sct. Nat. 37:461, 479. 1825.) and is currently treated as Nolletia chrysocomoides (Desf.| Cass. (1825, loc. cit.). Depending on the interpretation of the legitimacy 188 PHY TOLO GTA volume 77(3):141-297 September 1994 of Cassini’s combination, the species also has been treated as Nol- letia chrysocomoides (Desf.) Cass. ex Less. (Syn. Gen. Comp. 187. 1832.). Desfontaines originally described the species as Conyza (Fl. Atlant. 2:269, t.232. 1799.) but transferred it to Aster (Tabl. ecole bot. [ed. 2] 121. 1815.) after observing in cultivated plants of the species that the peripheral, pistillate flowers (normally only tubu- lar) sometimes produced evident ligules. Cassini did not believe these to be conspecific, but in any case, he explicitly indicated that he based his generic description of Nolletia on the type specimen of Conyza chrysocomozdes Desf., which was confirmed as Nolletia by Jones & Lamboy (1987). If Eurybia were typified with this species, Eurybia would replace Nolletia as the earliest name for this well- established, Old World genus of ca. ten species. 2. Aster tripolium L. This species is now sometimes treated as the monotypic genus Tripohum Nees (Gen. Sp. Aster. 10, 152. 1832.) and is accepted as such in the present overview of Aster and related genera. FEurybta would replace Tripoltum as the earliest generic name for this species, were it to be treated as a separate genus. 3. Aster corymbosus Aiton (= Eurybia corymbosa [Aiton] Cass. = Aster divaricatus L.). This species is a member of Aster subg. Bio- tra sensu Jones (1980a; also see Lamboy et al. 1991), part of a large North American segregate genus. If lectotypified py A. corymbo- sus, Eurybia becomes the legitimate name at generic rank for this group, which is recognized here for the first time as a distinct genus. Nees’s early treatment (1832) was unambiguous regarding the com- position of typical Hurybia, with the direct implication that Aster corymbosus should serve as the lectotype, but the formal designa- tion of that species is made here, apparently for the first time (see Appendix II). Tripolium and Nolletia have long been treated as separate genera; the names are clearly typified and well-established. Nees interpreted Eurybia as applicable to the North American biotian species, and early combinations by Nees and Cassini in Eurybia are available for some of those species. Cassini himself, however, was inconsistent in his enumeration of the constituent species of Eurybia, and as a result (at least partly), de Candolle’s association of the name with species of Olearza has persisted up to the present. Nevertheless, the long association of Eurybia with Olearia is unjustified; application of Eurybia to the North American species appears to be legitimate as well as pragmatically satisfactory. ; Nesom: Review of Aster taxonomy 189 B. Definition of the genus Eurybia The species of Eurybia are briefly characterized as follows: leaves and stems mostly glabrate, stipitate-glandular in a few species (EZ. spectabilis [Aiton] Ne- som, FE. pulchra[S.F. Blake] Nesom, £. conspicua [Lindl.] Nesom); leaves linear to obovate or cordate, venation parallel to pinnate but usually with 3-5 veins entering in parallel from the petiole base, with margins entire to serrate or spin- ulose, sessile, not clasping or slightly so in E. compacta Nesom; capitulescence loosely corymboid, reduced to 1 or a few heads in E. sibirica; receptacles com- monly distinctly foveolate, sometimes fimbriate as well; phyllaries in 5-7 series strongly graduated in length, often thickened, usually distinctly low-carinate, basally indurate with a sharply demarcated green apical patch (or “striate” in some species, see below), the inner often 3-veined, the margins minutely ciliate- fringed in most species groups ; disc flowers with style appendages ca. 1/5-1/2 the length of the branches, the appendages linear-triangular and mostly hairy (vs. papillate) from base to tip, but papillate in E. radulina (A. Gray) Nesom and with a similar tendency in some other western species; achenes narrowly oblong in outline, cylindric or subcylindric, (2-)3-5(-7) mm long, with 8-12(- 18) ribs, more or less stipitate basally, eglandular; pappus (1-)2-seriate, of flattened, often stiff bristles, these usually with dilated apices but slightly or not at all in a few species; and base chromosome number z=9 (NOR chro- mosome morphology of euaster type, but primitive type in E. glauca (Nutt.) Nesom and E. sibirica, fide Semple et al. 1983). Many of the species have a tendency to produce thickened leaves, and there is considerable variation in other foliar features. The disc corollas vary from narrowly tubular to long- tubed and abruptly ampliate in the distal third. Rays are mostly blue and coiling, but they are white and often little coiling in sect. Eurybia. The close connection between subg. Eurybia and subg. Heleastrum has long been recognized. Torrey & Gray’s original Aster subg. Calliastrum corresponds to sect. Calliastrum and subg. Heleastrum together; only later (1880, 1884) did Gray segregate Heleastrum s. str. into a separate subgenus. Gray (1880) made the further observation that subg. Heleastrum, sect. Biotia (= sect. Eurybia), and Sericocarpus (the latter treated as a separate genus by Gray) are closely related among themselves. Bentham’s concepts (1873) were similar: he in- cluded species of subg. Heleastrum within his sect. Calliastrum and placed the biotian species as a separate section. Bentham also held Sericocarpus as a distinct genus. Jones (1980a) placed sect. Eurybia (as sect. Biotia) with other sections in her subg. Aster; among the others were sect. Radulini and sect. Aster (includ- ing subsect. Calliastrum). In the analysis by Jones & Young (1983), sect. Fu- rybta was most closely related to Sericocarpus and to two other groups within subg. Aster (sensu Jones 1980a), sect. Calliastrum and sect. Radulin:z. Lam- boy et al. (1991) followed Jones & Young in observing that a close relationship 190 PHYTOLOGIA volume 77(3):141-297 September 1994 exists between sect. Eurybia, sect. Calliastrum, and sect. Radulini, but they added Doellingeria as a close relative to these instead of Sertcocarpus. They made no distinctions regarding the relative proximity of relationship among these four groups, nor did they provide specific comments regarding the bases for their hypotheses of relationship. The treatment by Semple & Brouillet (1980a) also was similar, as they placed sect. Eurybia closest to sect. Calhas- trum and part of sect. Radulini (these two groups consolidated within subsect. Aster). Burgess noted (1906, p. 60) that “I have not recognized this Biotian group (sect. Eurybia] as a genus, for it grades too imperceptibly into Aster species of the spectabilts group, especially in involucre, the chief character by which it had been separated.” The close relation between sect. Eurybia and sect. Calliastrum is emphasized by the occurrence of an intersectional hybrid. (see comments below under sect. Eurybia). . As hypothesized here, the closest relative of Eurybia is the genus Serico- carpus (see additional comments above and in the Introduction). Plants of these two genera are strikingly similar in phyllary morphology and at least some species of both retain a number of putatively primitive features (es- pecially multiseriate pappus of bristles with dilated apices and disc corollas abruptly ampliate distally). The resemblance in habit and leaf morphology of E. compacta (sect. Calliastrum) to Sericocarpus is particularly remarkable; it is interpreted here as parallel but indicative of close common ancestry. Simi- larly, Semple et al. (1983) correctly noted a resemblance in thizome morphol- ogy between Sericocarpus and some species of subg. Heleastrum. Eurybia and Sericocarpus are distinguished by the following contrasts: 1. Leaves stipitate-glandular in a few species, otherwise eglandular; heads distinct, pedicellate, somewhat congested in E. compacta; disc corollas yellowish, becoming reddish or purplish at maturity, narrowly tubular, in some species abruptly expanded into the throat; styve branch appendages mostly spreading hairy from base to tip; rays blue and strongly coiling, or mostly white and non-coiling in sect. Eurybta; achenes usually with a short stipe, glabrous to moderately strigose; NOR chromosomes of SUbster type. 6. eee Noe ein Noe bade se eteececs va eneen Ream Eurybia 1. Leaves sessile- or punctate-glandular; heads sessile or subsessile, in glom- erate clusters; disc corollas white, remaining so at maturity, broadly funnelform; style branch appendages papillate; rays white, not coiling; achenes not stipitate, sparsely densely strigose-sericeous; NOR chromo- somes of primitive type. ..........e cece e eee e nese eee e eens Sericocarpus Nesom: Review of Aster taxonomy 191 Subgenus Heleastrum Subg. Heleastrum comprises six species in three distinct subgroups endemic to the southeastern United States. It has been regarded as a separate genus by Greene (1896), Shinners (1949, 1969), and Correll and Johnston (1970), but the only recent treatment of all its species has been by Cronquist (1980), who retained it within a broadly conceived Aster. These are sometimes referred to as the “grass-leaved asters,” characterized by linear to narrowly oblanceo- late, sessile (not clasping), often crowded, mostly basally disposed, thickened and stiff, glabrous to glabrate leaves, a corymboid capitulescence (spicate in Eurybia hemispherica (Alexander) Nesom and E. spinulosa (Chapm.) Nesom, loosely paniculate in E. chapmaniz), blue, coiling rays, and narrowly tubular disc corollas with short, erect lobes. Jones (1980b) noted similarities between subg. Heleastrum, sect. Ozytri- polium, and subg. Virgulus (the latter two groups of the genus Symphyotrichum) in achene morphology, phyllary morphology, and the production of cormoid thizomes (particularly in Furybia hemispherica), and these similarities have also been part of the basis for other comments by Jones and by Sundberg (noted below) regarding hypotheses of close relationship between subg. Heleas- trum and sect. Ozytripolium. This also apparently reflected Jones’ early con- clusion that the base chromosome number of both groups was z=5. There also are similar tendencies in subg. Heleastrum and species of sect. Ozytripolium as well as others of subg. Symphyotrichum in the production of glabrous, narrowly lanceolate leaves, the upper grading into the phyllaries. Subg. Heleastrum was positioned as a specialized group within subg. Virgulus in the analysis of Jones & Young (1983), but morphological similarities between these two groups were attributed by Semple (1982) to evolutionary parallelism. Semple & Brouillet (1980a) placed subg. Heleastrum as an informal section within subg. Aster (sensu Semple & Brouillet 1980a), which also included other groups of Sym- phyotrichum (as “sect. Dumos?’), among others. Comments provided by Sem- ple regarding potential close relatives of subg. Heleastrum are the following (1982, p. 60): “Many morphological similarities exist between the less spe- cialized species of [subg.] Heleastrum and many species of sects. Aster and Sericocarpus of subgenus Aster” and (p. 67) Heleastrum is a “specialized off- shoot of the typical asters with A. paludosus Aiton being most like species in other sections.” The similarity perceived by Jones between subg. Virgulus and subg. He- leastrum underlay her hypothesis (1985) that z=9 in the latter is derived by aneuploid loss of one chromosome from an ancestral, presumably Virgulus-like tetraploid based on z=5 (2z = 10-1 = 9). The chromosome morphology of subg. Heleastrum does not support this idea, as the chromosomes are similar to those of the rest of Eurybia as well as subg. Symphyotrichum (euaster NOR type) but not to the highly specialized ones of subg. Virgulus. 192 PHYTOLOGIA volume 77(3):141-297 September 1994 Eurybia chapmanit is exceptional in its base chromosome number of z=7 (Semple 1982). Jones & Young (1983) hypothesized that this species origi- nated as a hybrid between z=9 species of subg. Heleastrum and r=5 species of Symphyotrichum sect. Ozytripoltum. Eurybta chapmanii also differs from others of subg. Heleastrum in its phyllaries, which are elliptic with a raised central nerve from base to tip and lack a distinctly delimited, green apical patch. It differs further in several features that are similar to those in plants of Symphyotrichum: relatively small heads in an open, somewhat paniculate- corymboid capitulescence and slender, terete pappus bristles without apical dilation. These features, along with its glabrous surfaces, give E. chapmani the appearance of sect. Ozytripolium. The immediate ancestry of E. chap- manit, however, appears to lie with other species of subg. Heleastrum on the basis of their similar habit, and leaf, capitular, and achenial morphology; the chromosome number of E. chapmanii is interpreted here as a reduction from z=9, in agreement with Semple (1982). Further, EF. chapmanzi produces a com- pacted rhizome and persistent cluster of linear basal leaves similar to those of E. eryngwfolia (Torr. & Gray) Nesom and E. spinulosa. Eurybia eryngttfolia and E. spinulosa are distinctive within subg. Heleas- trum in their spinulose leaves, persistent basal leaves, and their phyllaries without a strongly indurate basal portion but with anastamosing longitudinal strands that produce a distinctive, green-striate appearance. The phyllaries are notably similar to those of E. radula (Aiton) Nesom (sect. Radulint). If Heleastrum were treated as a separate genus, there would be little to recom- mend against its further fragmention by the segregation of E. spinulosa and E. eryngitfolia, as well as E. chapmaniti. C. Subgenus Eurybia Sections Radulini, Calliastrum, and Integrifoliae Eurybta radula and £. sazicastellii (Campbell & Medley) Nesom of the eastern United States are similar to western species, particularly EF. radulina and E£. conspicua, in their broadly obovate leaves with toothed margins and disc corollas with a long, narrow tube abruptly ampliate into a broad limb in the distal third. In their disc corolla morphology, they are similar to species of sect. Eurybta. Torrey & Gray (1841) noted that E. radula approaches the species of sect. Furybia, and the similarity of EF. radulain phyllary morphology to E. eryngitfolia and E. spinulosa of subg. Heleastrum has been noted above. Eurybia stbirica is remarkable within sect. Radulini in its low habit, few, loosely corymboid heads or reduction of the capitulescence to a solitary head, and herbaceous phyllaries of relatively even length, usually without a strongly developed, basally indurate portion or green apical patch. The connection of this species to others of sect. Radulini (particularly E. radulina) is seen in its © Nesom: Review of Aster taxonomy 193 closest relatives, E. merita(A. Nelson) Nesom and E. pygmaea (Lindl.) Nesom, which also tend to be reduced in habit but which have phyllary morphology more characteristic of others in subg. Furybia. As interpreted here, the loose, foliaceous phyllaries of EF. sibirica (and sometimes E. merita and E. pygmaea) are specialized. Three eurybian species of the eastern United States with entire leaves, a tendency to maintain the basal leaves, and narrowly tubular disc corollas are treated here as sect. Calliastrum. Similarities between these species and those of subg. Heleastrum are conspicuous. Torrey & Gray (1841) included Aster paludosus (sect. Heleastrum) as a member of their subg. Calliastrum. Cron- quist (1980, p. 156) noted that Eurybia compacta “approaches A. surculosus Michx., on one hand, and A. paludosus and A. avitus, on the other.” Eurybia surculosa (Michx.) Nesom is particularly similar in habit and leaf morphology to plants of sect. Heleastrum. Eurybia integrifolia (Nutt.) Nesom is seemingly isolated within the genus and is treated here as a monotypic section. It is distributed in montane habi- tats of the northwestern United States and characterized by large, entire, per- sistent basal leaves, a densely long-stipitate glandular vestiture, and relatively large heads in an elongate to nearly spicate capitulescence. Section Herrickia A distinctive species from northern New Mexico and adjacent southern Col- orado was originally recognized by Wooton & Standley (1913) as the monotypic genus Herrickia (H. horrida Wooton & Standl.). Blake (1937) subsequently transferred the species to Aster, noting that its closest relative appeared to be Eurybia [Aster] wasatchensis (M.E. Jones) Nesom. Herrickia horrida was not included in the taxonomic surveys of Aster by Jones (1980a) or by Semple & Brouillet (1980a), its position as a monotypic genus perhaps accepted by these botanists. It was recently included within Aster in a recent treatment of the New Mexico flora (Martin & Hutchins 1981) but treated as monotypic Herrickia in recent checklists (Kartesz & Kartesz 1980; Weber & Wittman 1992; Kartesz 1994). Eurybia horrida (Wooton & Standley) Nesom is immediately recognized by its subshrubby habit often with numerous stems arising from near the base, its evenly arranged, epetiolate, subclasping, stiff and regularly crenate- spinulose leaves, stipitate-glandular vestiture, and loose phyllaries in 3-4 series of nearly equal length. But the corymboid capitulescence, bluish and coiling rays, narrowly tubular, reddening disc corollas with linear-lanceolate collect- ing appendages hairy from base to tip, narrowly cylindric, glabrous achenes, and the base chromosome number of z=9 of E. horrida are similar to those commonly produced by other species of Eurybia. Although the phyllaries are 194 PHYTOLOGIA volume 77(3):141-297 September 1994 specialized, they tend to produce a distinct, basally truncate apical patch like other species of Eurybia; the inner phyllaries are keeled and usually have an indurate-chartaceous base. Thick, nearly coriaceous leaves, with margins rang- ing from entire to distinctly spinulose-toothed, also occur in subg. Heleastrum and a glandular vestiture and subclasping, thick, coarsely serrate leaves are characteristic of species of sect. Radulini. Eurybia wasatchensis is treated here in the same section as £. horrida, in agreement with the early observation by Blake of their similarity, particularly in their habit, sessile, subclasping leaves, subequal phyllaries, and tendency to produce foliaceous bracts immediately subtending the involucre. The former species differs from E. horrida primarily in its somewhat thinner, entire leaves and lightly strigose achenes. Eurybia glauca (= Aster glaucodes S.F. Blake) of the western United States, is similar in habit to E. horridaand E. wasatchensis and produces short thick, entire, subclasping leaves with a similar gray-green color. The phyllaries of E. glauca, however, are strongly graduated in length and foliaceous bracts are absent. The achenes produce an unusually large number of nerves (14-18), but in other features this species seems to fit well within Furybia, notwithstand- ing its previous association with Fucephalus and Symphyotrichum turbinellum (Lindl.) Nesom (Jones 1980a; Semple & Brouillet 1980a; Jones & Young 1983). Eurybia pulchra, previously recognized as a variety of Aster glaucodes, is treated here at species rank and included within sect. Herrickia; it differs from E. glauca in its smaller leaves, apically acute phyllaries, and well-developed glandularity, which is relatively uncommon in the genus but which does occur in similar form in E. spectabilis and E. horrida. Eurybia pulchra has a restricted geographic range, and in the specimens I have examined, there appears to be no intermediacy between it and E. glauca. Cronquist (1994) placed E. pulchra as a synonym of E. wasatchensis; his comment regarding a degree of intermediacy between the latter and E. glauca almost certainly stems from the generally unrecognized existence of E. pulchra. Section Eurybia Sect. Eurybia comprises seven species endemic primarily to montane and temperate forest habitats in the eastern United States. These have recently been studied in detail by Lamboy and colleagues (see Literature Cited). Within Eurybia, the plants are characterized primarily by the following features: basal and lower cauline leaves with cordate blades on long, non-clasping petioles, © disc corollas with a long, narrow tube abruptly ampliate in the distal 1/3-1/4 ; to a much broader limb, the lobes deeply cut and erect to slightly loose or : reflexing, and the ligules white to light lavender and only weakly coiling if i at all. The ovate-cordate, long-petiolate basal leaves are similar to those of — Nesom: Review of Aster taxonomy 195 some species of Symphyotrichum sects. Concinnt and Cordifolt, Doellingerza, as well as some Solidago, but this foliar morphology apparently has developed in parallel in each of these groups. Without basal leaves, however, plants of sect. Eurybia are strikingly similar in overall aspect to some of Eurybia sect. Radulini. In sect. Eurybia, the white, little coiling ligules and abruptly am- pliate disc corollas with long lobes are similar to Doellingerza and genera of Solidagininae hypothesized to be primitive within the subtribe. Similar disc corollas also occur in sect. Radulini. Eurybia x herveyt (A. Gray) Nesom is a natural, recurring, intersectional hybrid between FE. macrophylla (L.) Cass. (sect. Eurybia) x E. spectabilis (sect. Calliastrum) that forms clonally persistent colonies of at least partially fertile plants. The hybrid nature of these has been confirmed by experimental crosses (Uttal 1962). The F,’s are usually more similar to the biotian parent than the other, but introgressant populations occur. Both parents are reported to have a hexaploid chromosome number, a fact almost certainly connected with the observation of a high degree of variability among the F, progeny of these species. According to Lamboy et al. (1991), the origin of E. macrophylla itself probably is complex; they speculated that its parentage might involve some species outside the group of its immediate relatives (sect. Eurybia), but no other species were included in their analyses. VII. Oreostemma Oreostemma is a sharply delimited group of three species of western North America (Cronquist 1948; Nesom 1993a). One of the species, O. elatum (E. Greene) E. Greene, was regarded as a synonym of O. alpigenum (Torr. & Gray) E. Greene in a recent summary of Californian Aster by Allen (1993). The plants are herbaceous, taprooted (sometimes thick-rhizomatous) perenni- als with monocephalous, essentially scapose stems arising from a basal rosette of linear to narrowly oblanceolate, entire, 3-nerved leaves. One remarkable in- dividual of O. alpigenum var. haydenit (T.C. Porter) Nesom from Utah ( Recker 4255 [US]) has spinulose leaf margins. Oreostemma peirsonti (C.W. Sharsmith) Nesom has a glandular vestiture, otherwise the plants are eglandular; the up- per stems and phyllaries commonly are finely and loosely tomentose. The phyllaries are in 3-4 series of about equal length, nearly completely foliaceous (basal margins of at least the inner are indurate in O. elatum and some in- dividuals of O. alpigenum), sometimes with evident stomates, and often with a low but evident keel. Disc corollas are tubular with short, erect lobes and remain yellowish at maturity; the style branch appendages are extremely long, commonly reaching 2 mm. Achenes are narrowly cylindric, 4-5 mm long, with 5-10 raised nerves, glabrous or sparsely short-strigose; the pappus is mostly l-seriate but sometimes has a few short bristles or setae in a second series. 196 PHYTOLOGIA volume 77(3):141-297 | September 1994 The base chromosome number of Oreostemma is z=9. My characterization (Nesom 1993a) of its NOR chromosome morphology as the primitive type was was inferred from the placement by Semple & Brouillet (1980a) of Oreostemma as a subgenus separate from subg. Aster, the latter including all the species with the euaster type NOR morphology (except Sericocarpus). But apparently the only published illustration and description of the karyotype of Oreostemma has been by Huziwara (1958 - O. alpigenum), who did not observe the NOR morphology. I hypothesized earlier that the relationships of Oreostemma might lie with the South American genus Oritrophium, but the latter is now included as a member of the subtribe Hinterhuberinae (Nesom 1994e), and Oreostemma is distantly related to that group. VIII. Ampelaster Ampelaster carolinianus (Walt.) Nesom, which has been recognized as the sole species of Aster sect. Sagzttiferi, is endemic to the Atlantic coastal plain from Florida to North Carolina. It is treated here as a monotypic genus and is briefly characterized as follows: perennial, eglandular herbs from a woody base, vines or at least with a distinctly scandent tendency; stems densely hir- sutulous or pilosulous; leaves oblanceolate to oblong-oblanceolate, 1-nerved, auriculate-clasping at the base; heads relatively large, blue-rayed, solitary or 2-8 in short-pedicellate, loose, terminal clusters; phyllaries thick, linear-oblong, subequal in length, low-keeled, with a pronounced, nearly truncate (but some- times basally attenuate), foliaceous apical patch, usually apically reflexed; disc style branches with collecting appendages relatively short (ca. 1/3 the branch length); pappus l-seriate, the bristles apically attenuate; achenes narrowly cylindric or slightly fusiform, 2.5-3.0 mm long, glabrous, with 9-12 whitish, slightly raised ribs, sometimes with purplish pigmentation (at maturity); and chromosome number of n=9. Ampelaster carolinianus was included within Virgulus by Semple & Brouil- let (1980a) and maintained there by Reveal & Keener (1981) as Virgulus sect. Sagittiferi. The chromosome number of this species, however, has proven to be z=9 (Jones 1985; S. Sundberg unpublished) rather than z=5 invariably characteristic of subg. Virgulus, and its morphological features are equivocal in suggesting a generic placement. It is similar to some species of Symphy- otrichum sect. Symphyotrichum as well as to S. novae-angliae (L.) Nesom and others of subg. Virgulus in its sessile-auriculate leaves and narrow, subequal phyllaries, and 1-seriate pappus, but its chromosome number of z=9, eglandu- lar vestiture, long, narrowly cylindric achenes, and the tendency for aggrega- tion of heads suggests that it is not far removed from the primitive species of Eurybia. The species might be accreted to Symphyotrichum, especially in view Nesom: Review of Aster taxonomy 197 of the taxonomic conjunction maintained here between subg. Symphyotrichum and subg. Virgulus, but it appears to occupy an isolated, seemingly interme- diate phyletic position between Eurybia and Symphyotrichum, and other taxa (Psilactis, Canadanthus, Almutaster) appear to be more closely related to Sym- phyotrichum than is Ampelaster. Ampelaster differs from all other species of Asterinae in its scandent to subscandent habit and will hardly be mistaken for any other species. IX. Almutaster The monotypic Almutaster (= Aster sect. Pauciflori = Aster pauctflorus) was recently segregated by Love & Love (1982). The species is distributed from south-central Canada through the western United States into south- central México. Plants of Almutaster are characterized as follows: rhizoma- tous, perennial herbs with stipitate-glandular vestiture and well-developed, linear-lanceolate, non-clasping, 3-nervate, entire, cauline leaves margined by a narrow, white, smooth rim (the few persistent basal leaves sometimes oblance- olate to oblong-spatulate); capitulescence loosely corymboid or sometimes re- duced to a single head; heads small with white rays; phyllaries pauciseriate and only weakly graduated in length, without a distinctly developed apical patch and with stomates often evident on the distal portion; disc corollas remaining yellowish at maturity; narrowly subcylindric achenes 1.7-2.5(-3.5) mm long, with 8-12 nerves and 1-seriate pappus; base chromosome number, z=9. A number of botanists have noted the morphological similarity between Almutaster and the species of Psilactis, particularly in their densely glan- dular indument with few or no eglandular hairs and their relatively small, fusiform achenes with numerous, pronounced ribs (e.g., Shinners 1949; Sund- berg 1986; Hartman 1990; Morgan & Simpson 1992; Morgan 1993). Semple et al. (1989) noted the similarity between Almutaster and Symphyotrichum sect. Ozytripolium (presumably in their hydrophilic tendency, linear-acute leaves, and small, white-rayed heads in a loose corymboid inflorescence) and suggested that Almutaster pauctflorus (Nutt.) Love & Love (with base chromosome num- ber of z=9) may be an allopolyploid combining the z=4 genome of a Psilactis species and the z=5 genome of one of sect. Orytripolium, apparently relinquish- ing an earlier hypothesis (Semple et al. 1983) suggesting that A. pauczflorus is most closely related to Eurybia integrifolia and Aster modestus Lindl. (the latter treated here as Canadanthus). Jones & Young (1983) suggested that A. pauciflorus should be interpreted as a hybrid derivative between Machaeran- thera (probably referring to Psilactis) and sect. Orytripolium. Sundberg (1986) considered the possibility that A. pauciflorus may be an alloploid derivative of a cross between a species of Symphyotrichum subg. Virgulus and Psilactis. The hypothesis that Almutaster pauciflorus is an alloploid has arisen from morphological observations, but it has not been supported by other lines of ev- 198 PHYTOLOGIA volume 77(3):141-297 September 1994 idence. Gottlieb (1981) found that A. pauctflorus (as well as Psilactis brevilin- gulata Sch.-Bip. ez Hemsl. , also with n=9) produced about the same number of isozyme loci as three other Psilactis species, each with z=4, rather than the doubled number expected for a species of allopolyploid origin. Further, the karyotype of A. pauciflorus is markedly symmetrical (Stucky & Jackson 1975), showing no chromosomal evidence of disparate parentage. The molecu- lar (cpDNA and nuclear rDNA) data of Morgan (1993) place the z=9 species of Psilactis (including A. pauctflorus) in a primitive or at least coordinate phyletic position relative to the species with lower numbers. Almutaster pau- ciflorus does not have an amount of nuclear DNA double that of its putatively close relatives with n=4, which might be expected if its origin had been through alloploidy (Stucky & Jackson 1975), although these data and their interpre- tation are problematic (see Jackson et al. 1993 for comments and references; also Michaelson et al. 1991). There are no documented hybrids between Almutaster pauciflorus and species of Psilactts. Sundberg (1986) made unsuccessful attempts to produce these experimentally. In his study, all attempts to produce hybrids among z=4 species of Psilactis, r=9 A. pauciflorus, z=5 species of sect. Orytripolium, and z=9 Aster tripolum were completely unsuccessful. In contrast, Stucky (1978) reported that he produced artificial hybrids between Psilactis tenuis S. Wats. and P. asteroides A. Gray (both z=4) as well as intergeneric hybrids between A. pauciflorus and each of two z=5 species of Machaeranthera (M. arida [Kunth] A.G. Jones and M. parviflora A. Gray). In summary, evidence from DNA studies suggests that Psilactis is close to Symphyotrichum although genomic similarities suggest that the phyletic distance between Psilactis, Al- mutaster, and even Machaeranthera also may be relatively small (see Nesom 1994f for comments on hybridization). X. Psilactis Psilactis includes six species (sensu Morgan 1993) distributed from the southwestern United States into south-central México, with one species essen- tially continuing into northwest South America. They are similar among them- selves in their tendency to inhabit moist or wet habitats, stipitate-glandular vestiture, clasping to subclasping leaves, small heads with white to bluish rays and other details of floral and fruit morphology, particularly their epappose ray achenes. Pstlactts odysseus (Nesom) Morgan is rhizomatous and perennial, with monocephalous stems; the others are taprooted and annual or short-lived perennial in duration, with a loosely paniculate capitulescence. The phyllar- ies are only weakly graduated in length and tend to be mostly herbaceous although they may be indurated along the basal margins. Achenes are short- © elliptic to broadly obovate, 1-3(-4) mm long, somewhat compressed, 5-14(-18) Nesom: Review of Aster taxonomy 199 nerved and produce a l-seriate pappus of apically attenuate bristles. The two most divergent and apparently most specialized species (P. odysseus and P. brevilingulata) have a base chromosome number of z=9, while the other four have z=4 or z=3. The group has received detailed study (Turner & Horne 1964; Stucky 1974; Nesom 1978; Arnold & Jackson 1979; Hartman & Lane 1987; Morgan 1993). Psilactis has been regarded as a subgroup within the genus Machaeranthera in recent treatments (Turner & Horne 1964; Stucky 1974; Hartman 1990). Cu- atrecasas (1969) treated it separately, however, and Morgan (1993) returned the whole group to generic rank with a revisionary study and several new combinations. Until relatively recently, all of Machaeranthera commonly was submerged within Aster (Cronquist & Keck 1957), but the particular basis for the association of Psilactts with Machaeranthera (as part of sect. Arida R.L. Hartman) has proven to be a convergent similarity both in vegetative and achenial features. Pstlactis was not included in the analysis by Jones & Young (1983), but two species of the group were included within Aster by McVaugh (1984). Shinners (1949, p. 54) noted in his description of a new species of Psilactis (as a genus) that “It has remarkable superficial resem- blance to Aster pauciflorus Nutt. and its Mexican allies” (the latter evidently referring to taxa of sect. Ozytripolium). Turner & Horne (1964) referred to Psilactis s. str. as “Aster-like” in habit; they commented on the vegetative similarity between sect. Ozytripoltum and Psilactis, although they regarded it as superficial because of other similarities between Ps:lactis and Machaer- anthera that were more significant, in their view. Based on chloroplast DNA restriction site variation (Morgan 1993), species of Pszlactzs are cladistically intermixed with species of Ozytripolium, and Psilactis is paraphyletic without sect. Ozytripolium. Morgan’s data from nuclear ribosomal DNA, however, sup- port the treatment of Psilactis as a separate group and place sect. Orytripolum closer to subg. Symphyotrichum and subg. Virgulus. Despite the often invoked association between Pstlactts and Almutaster pauciflorus, the two are different in significant features: in A. pauczflorus the leaves are stiffly linear and slightly sheathing at base (vs. looser in texture, broader, and distinctly subclasping, sometimes auriculate), the capitulescence tends to be corymboid (vs. loosely paniculate), the phyllaries usually not dif- ferentiated into an indurate base and green apical region (vs. indurate basal region sometimes evident), and the ray achenes are pappose (vs. epappose). Morgan’s reinstatement of Psilactts as a genus was based on the following reasoning. Based on DNA data, it is clearly separate from Machaeranthera and close to North American species generally treated within Aster, although his molecular data were not conclusive regarding the nature of their interrela- tionship. Morgan declined to combine Psilactis with Aster, because (p. 296) “the result would only increase the morphological and cytological diversity in a genus that is already diverse and poorly understood.” Further, he ob- 200 PHYTOL @GTA volume 77(3):141-297 September 1994 served a suggestion of genetic influence from Machaeranthera, as seen in the apparently “Machaeranthera-like” morphological features of Pszlactis (1.e., low chromosome number, tap-rooted habit, leaves with spinulose lobes, lack of ray pappus). Psilactis stands as a relatively isolated group, but similar Machaeranthera- like features (except epappose achenes) also occur in various other species and groups within New World asters, and Psilactis has particularly notable similarities with other taxa placed here in Almutaster and subg. Virgulus. XI. Canadanthus The species identified as Aster modestus Lindl. is here segregated as a. monotypic genus, Canadanthus, and characterized as follows: perennial, thin- rhizomatous herbs, the stems simple and arising singly from the base, 3-8 dm tall; vestiture of long-stipitate glands (stems and phyllaries), without other hairs; leaves all cauline, eglandular, glabrate to thinly short-strigose above, loosely and thinly pilosulous beneath, epetiolate, subclasping, lanceolate to elliptic-lanceolate with an acuminate apex, entire to serrate, 5-12 cm long, 15-25(-40) mm wide, the lowermost strongly reduced in size; capitulescence loosely corymboid, mostly 3-20 flowered, less commonly 1, sometimes many more, and the capitulescence thyrsoid, heads on leafy peduncles, mostly 2-4(-6) cm long, usually with 1-3 reduced leaves or bracts; phyllaries linear-lanceolate, flat, in 2-3 series of nearly equal length, thin-foliaceous, without a green apical patch or indurated basal region, the inner often with a slightly raised keel and usually strongly purplish; disc corollas narrowly tubular, 5-7 mm long, with short, erect lobes; disc style branches 1.0-1.4 mm long, the collecting appendages triangular, hairy, more than half the length of the branches; ray corollas 25-40 with purple, coiling ligules; achenes oblanceolate with a narrowly acute, stipitate base, 2.5-4.0 mm long, strongly flattened, 4-8 nerved, and eglandular; pappus 1(-2)-seriate; and chromosome number of n=9. It occurs from Alaska southward to Washington and Oregon, and eastward through Alberta to eastern Ontario and Minnesota. The singly produced, unbranched stems of plants of Canadanthus modes- tus produce a habit similar to those of some species of Eurybia (particularly sect. Eurybia) and Oclemena. In his description of Aster sayianus Nutt. (a synonym of A. modestus), Nuttall (1841, p. 294) noted that “This species has much the habit of a Galatella,” probably referring to Oclemena (Aster) nemoralts, for which he accepted Nees’s early referral to Galatella (see Ap- pendix II). Jones (1980a) and Jones & Young (1983) placed Aster modestus with Eurybia radulina. Semple & Brouillet (1980a) informally separated Aster modestus and Eurybia stbirica and set them together distantly apart from most other z=9 and r=8 taxa as Aster “subg. Modesti;” Semple et al. (1983) viewed Nesom: Review of Aster taxonomy 201 Almutaster (Aster) pauciflorus as closely related to Canadanthus, citing sim- ilarities in habit, phyllaries, and achenes, but they did not reevaluate their earlier positioning of A. modestus. Nuttall also noted that his Aster sayianus is “Nearly allied to A. mod- estus, and proximately to A. novae-angliae.” The similarity of these latter two species is immediately evident and often has been referred to directly, as in Nuttall’s observation, or indirectly, particularly as the two species tend to fall out together in identification keys. They are similar in their stipitate- glandularity, clasping cauline leaves, heads on leafy peduncles, purple rays, linear, purple phyllaries of nearly even length, and oblanceolate achenes with a tendency for reduced pappus. The capitulescence of A. modestus tends to be corymbiform and the heads are borne on leafy peduncles and are loosely associated, more like capitulescences found in Symphyotrichum (particularly S. novae-angliae) than in Eurybia, Oclemena, or other putatively primitive genera with a corymboid arrangement of heads, usually on peduncles with few or no bracts. A combination of morphological and chromosomal features, however, sug- gests that Canadanthus is phyletically separated from Symphyotrichum subg. Virgulus: leaves are relatively broad, thin, and with toothed margins (vs. nar- tow, thick, and entire); phyllaries are completely without an apical patch; stems arise singly from the base; achenes are strongly flattened; and the pap- pus sometimes is formed of two distinct series of equal-length bristles. Similar comparisons were made by Jones (1980b). The habit, vestiture, phyllaries, achenes, and pappus of Canadanthus remove it from sug. Symphyotrichum. Its chromosome number of n=9 (with “primitive” NOR morphology, fide Sem- ple et al. 1983) also places Canadanthus in a more basal position than any species of Symphyotrichum. In summary, C. modestus ‘s here considered to be closely related to Symphyotrichum, but it appears to occupy an isolated position at least as distinct from the latter as Almutaster, Psilactis, and Am- pelaster. Although some practical problems in identification may be associated with the recognition of this monotypic genus, its amalgamation with Symphy- otrichum would require for consistency that these other distinct and isolated taxonomic elements also be added. XII. Symphyotrichum The greatest number of species identified here as Symphyotrichum have re- cently been classified as Aster subg. Symphyotrichum (Jones 1980a). These are the species with base chromosome numbers of z=8 and z=7. To these is added a closely similar group of species previously recognized as sect. Ozrytripolium, which have base chromosome numbers of z=6 and z=5; the accepted num- ber of species in this section is considerably enlarged (past that of Sundberg 202 PHYTOLOGIA volume 77(3):141-297 September 1994 1986) in the present discussion. Symphyotrichum is further broadened by the incorporation of the z=5 species previously segregated as the genus Virgu- lus. Symphyotrichum is divided into two subgenera, subg. Symphyotrichum (8 sections, 76 species) and subg. Virgulus (4 sections, 21 species). Naturally formed, relatively fertile hybrids occur between species of Sym- phyotrichum of disparate morphology, of different chromosome numbers, and of different sections and subgenera (Figure 2). Such wide crosses are known to occur between (2) various combinations of species in different sections of subg. Symphyotrichum, including sect. Dumosi and sect. Orytripolium, and (2) sect. Occidentales (subg. Symphyotrichum) and sect. Oblongifolit (subg. Virgulus). Symphyotrichum subg. Symphyotrichum appears to be monophyletic, based on a remarkable consistency in the achene morphology, lack of glands, produc- tion of stem hairs in lines, and in phyllary morphology. The group is more specialized in these respects than is Virgulus, which retains a number of rela- tively unspecialized features and which could not have been derived from subg. Symphyotrichum. Correspondingly, reduction of the base chromosome number from z=9 to z=8 and z=5 in these two groups appears to have occurred inde- pendently. Despite strong evidence for the discrete nature of these two groups, hybrid species and introgressants produced across different levels of ploidy (see discussion below) indicate that the genetic divergence between Virgulus and species of subg. Symphyotrichum is relatively slight (see Nesom 1994f), in spite of differences in morphology, chromosome number, and karyotype. These two groups are treated here as congeneric to avoid intractable problems in practical taxonomy (i.e., how to deal with the intersubgeneric hybrids and backcrosses). As noted by Allen (1985, p. 276), the apparent close homology between these z=5 and z=8 genomes offers “a counter to recent suggestions for removing the z=5 elements of Aster into a separate genus.” The other generic level groups that are most closely related to Virgulus and Symphyotrichum (i.e., Psilactis, Almutaster, Canadanthus) might also be included as subgenera within Symphyotrichum, especially in view of their base chromosome number of z=9 and the evident paraphyly of Symphyotrichum and Virgulus without the inclusion of z=9 species, from which the z=8’s and z=5’s clearly have been derived. Each of the apparently basal groups, however, is morphologically and genetically discrete, and the nature of their relationship to Symphyotrichum s. lat. is not clearly evident. Typification of Symphyotrichum The genus Symphyotrichum was established by Nees, the single species, S. unctuosum Nees, based on a horticultural specimen transmitted to Germany from Glasgow. Nees described the pappus of this plant as coherent in a basal ring (whence the generic name), but this tendency must be rare since it is not © Nesom: Review of Aster taxonomy 203 characteristic of any species of Symphyotrichum; thus, while the application of Nees’s name to this large group of species is legally required, it is peculiar. De Candolle (1836, or “Lindley ez de Candolle”) and Torrey & Gray (1841) early recognized and reported the identity of S. unctuosum with Aster tardiflorus L. Gray (1884) later placed S. unctuosum as a synonym of Aster novi-belgi var. litoreus A. Gray, and Jones (1980a) noted simply that S. unctuosum was synonymous with A. novt-belgit. As observed by Jones & Hiepko (1981), A. novi-belgii and A. tardiflorus are very similar and often intergrade, and they are considered to be conspecific in the present treatment (as Symphyotrichum novt-belgit). The larger species group of which S. novi-belgi: is a member has recently been identified as Aster subg. Symphyotrichum (Jones 1980a). A. Subgenus Symphyotrichum Fight sections within subg. Symphyotrichum are recognized here, these corresponding to previously recognized and closely associated species groups, except for the addition of sect. Orytripolium. The species of the subgenus are characterized by their reduced vestiture except for the tendency to produce hairs in lines on the stems, lack of glands, unkeeled (or only slightly keeled) phyllaries usually with a sharply defined, basally attenuate apical patch (often with stomates visible), achenes somewhat foreshortened to a narrowly obovate shape, (1.0-)1.5-3.5(-4.0) mm long, distinctly flattened to varying degrees, and with (2-)3-5(-6) nerves, and base chromosome number of z=8, independently reduced to z=7 and to z=6 or z=5 in specialized sections. The capitulescence is generally paniculate, with the heads scattered in a relatively loose orga- nization. It may sometimes appear broadly pyramidai or columnar, or the peduncles may be very short and arrangement of heads racemoid or nearly spicate. If the capitulescence appears corymboid, the peduncles usually bear a number of reduced leaves or bracts, unlike the mostly naked peduncles in the corymboid cymes of Eurybia. The species vary in habit, duration, leaf mor- phology (shape, insertion, and distribution), head size, phyllary morphology, and ray color. Through reinterpretations of previous chromosome counts and the addition of many new ones for species of subg. Symphyotrichum, Jones (1977) estab- lished that the base number for the group is z=8. Remaining meiotic counts of n=9 pairs within the group have further been suggested to be based on su- pernumerary chromosomes (Semple e¢ al. 1983). Further, it is clear that some aneuploidal instability in chromosome number may exist among these species, particularly in polyploids (e.g., Allen 1985; Legault & Brouillet 1989). There are many hybrids and intergrading forms among the species of subg. Symphyotrichum, mostly between those within a section, but the relatively common occurrence of intersectional hybrids emphasizes the coherence of this 204 PHYTOLOGIA volume 77(3):141-297 September 1994 large group. Polyploidy is common and presumably contributes to the ease with which fertile hybrids are formed. Jones (1980b, p. 241) has observed that many of these species “have extensive geographic ranges and are extremely heteromorphic” and might be viewed as “ecological species” (sensu Van Valen 1976). They may be “influenced more by populations of other species with which they are sympatric than by geographically distant populations of the same species.” Semple & Brammall (1982), in contrast, noted that much of the taxonomically confusing variation among these species may be more at- tributable to phenotypic plasticity than to hybridization. Judging, however, from the formal taxonomic complexity admitted for some of the species com- plexes (e.g., Semple & Chmielewski 1987), more than phenotypic plasticity must be held responsible for the general form of some of the variation pat- terns. Features of foliar morphology in some species of subg. Symphyotrichum are shared with those of subg. Virgulus and Psilactts, as well as some species of Eurybia, especially the epetiolate, more or less oblong, clasping to subclasping cauline leaves. This set of features is interpreted as the unspecialized condition. In sect. Symphyotrichum and sect. Occidentales, where this morphology is pronounced, there also is a distinct tendency for corymboid or subcorymboid capitulescence, also an unspecialized condition in the Eurybian lineage. The sessile, non-clasping cauline leaves and the diffuse capitulescence characteristic of most species of sect. Dumosi and sect. Ozytripolium is specialized. Sects. Ozytripolium and Conyzopsis are particularly distinct groups, each with a derived chromosome number and specialized morphology, both regarded as separate subgenera in earlier treatments (e.g., Jones 1980a) or even as sep- arate genera (see below). Sect. Conyzopsis (z=7) is similar in significant re- spects to sect. Occtdentales (see below); the distribution of these two groups is primarily in the western United States, in contrast to many other Furybia, and they appear to be genetically isolated as well, judging from the lack of natural hybrids with the rest of the genus (Figure 2). There are many similarities between sect. Ozytripolium (z=6,5) and sect. Dumosi (z=8) and natural inter- ploidal hybrids apparently are formed between the two sections (see below). The position of Aster carnerosanus Symphyotrichum (Aster) carnerosanum (S. Wats.) Nesom was placed (with a question) by Jones (1980a) among the species of her subsect. Spectabiles, which have a base chromosome number of z=9. She later acknowledged its morphological alliance with subg. Symphyotrichum (Jones 1984), and it is similarly placed in the present treatment as a member of sect. Dumosi (subsect. Divergentes). Morgan (1993) assigned a chromosome number of n=9 to this Nesom: Review of Aster taxonomy 205 species, but a documented chromosome count for 5. carnerosanum apparently has not yet been published. Based on the present classification, the species is predicted to have a number of z=8. The position of Aster turbinellus The taxonomic position of Symphyotrichum [Aster| turbinellum has been the subject of considerably different interpretation. Semple & Brouillet (1980a) regarded it as belonging among the species of Eucephalus. Jones (1980a) treated S. turbinellum within Aster sect. Eucephalus subsect. Turbinellt, which included only one other species, Aster glaucodes (placed here within subg. Eurybia sect. Calliastrum), hypothesizing shortly thereafter (Jones & Young 1983) that it might be of hybrid origin. Still later (1989), she has treated it as a monotypic section of subg. Symphyotrichum. Although S. turbinellum is an unusual species, a combination of features suggests that it belongs with subg. Symphyotrichum: stem hairs in lines, an open-paniculate capitulescence, phyl- laries with a sharply delimited, basally attenuate apical patch, slender pappus bristles of even length and with acute apices, and a base chromosome number (apparently) of z=8. The chromosome number of S. turbinellum was first re- ported as n=50 (Avers 1957; Jones 1980b), but recent reinterpretations and recounts (Semple & Brouillet 1980a; Semple et al. 1983) show the number is apparently n=48 (or 2n=96), here interpreted as dodecaploid based on z=8. Other features suggest that within Symphyotrichum it is closest to the species of sect. Concinni (this proximity much earlier observed by Asa Gray 1884): petiolate, often truncate or subcardate basal leaves, thick, stiff cauline leaves, slightly keeled phyllaries, and turbinate heads in a very open panicle, borne on long, bracteate peduncles, with the uppermost pedunculai bracts grading into involucral bracts. The achenes of S. turbinellum are typical of those within subg. Symphyotrichum; they are 4-5 nerved, obovate-oblong, and slightly com- pressed; the pappus is 1-seriate. The position of Aster retroflerus Symphyotrichum retroflerum (DC.) Nesom (Aster retroflerus Lindl. ex DC. = A. curtis Torr. & Gray) was placed in sect. Calliastrum by Torrey & Gray (1841), although they noted that it might belong instead with sect. Grandiflorz (subg. Virgulus); the species was maintained within the Calliastrum group by Gray (1884). Jones (1980a) viewed it essentially as did Gray, placing it in sect. Spectabiles. With a chromosome number of z=8 recently confirmed for the species (Jones 1983b), however, she transferred it to a position among other z=8 taxa in subg. Symphyotrichum, noting morphological similarities to S. laeve (L.) Love & Love and S. oolentangiense (Riddell) Nesom (sect. Concinni 206 PHYTOLOGIA volume 77(3):141-297 September 1994 in the present treatment). Semple et al. (1983) suggested that it belongs with S. novt-belgit and S. puniceum (L.) Love & Love of subg. Symphyotrichum (sect. Symphyotrichum). Symphyotrichum retroflerum is characterized by nearly glabrous stems, leaves, and phyllaries (or stem hairs barely evident and in lines), petiolate, basal leaves with truncate or subcordate blades, sessile and non-clasping cauline leaves, few and relatively large heads usually racemoid to nearly spicate but sometimes more loosely arranged, with keeled, squarrose phyllaries with a sharply demarcated, basally truncate apical patch and convex, white-indurated base, and glabrous, slightly flattened, oblong-oblanceolate, 4-5 nerved achenes with a l-seriate pappus of apically attenuate bristles. The disc corollas are abruptly ampliate into the throat with deeply cut lobes; this primitive mor- phology occurs in some species of EHurybia as well as Symphyotrichum sect. Cordifoliz. Particularly in its large heads and their arrangement, phyllary morphology, and corolla morphology, the species does have a remarkable re- semblance to some in Eurybia sect. Calliastrum, but its combination of cauline vestiture, leaf shape, achene and pappus morphology, and chromosome number provide evidence for placing it in subg. Symphyotrichum. The status of Brachyactts s. str. There are three species of Brachyactis s. str. (= Symphyotrichum sect. Conyzopsis, as treated here): two are endemic to North America and the third (S. ciliatum, the generitype, = Aster brachyactis S.F. Blake) is widespread in North America and across the North Pacific to northcentral and northeastern Asia (the type collected in Siberia). The latter species is unusual among species of Asters. lat. in its bicontinental, nearly circumpolar, distribution. A nomenclatural summary for the group is available (Jones 1984), amended by the observation that Symphyotrichum laurentianum (Fernald) Nesom is a distinctive species rather than a part of S. ciliatum (Gleason & Cronquist 1963, 1991; Houle & Brouillet 1985; Houle & Haber 1990). The species of sect. Conyzopsis were treated as Aster subg. Conyzopsis by Jones (1980), informally as “sect. Brachyactis” of subg. Aster by Semple & Brouillet (1980a), as Aster sect. Conyzopsis by Houle & Brouillet (1985), and as Aster “subg. Brachyactis” by Nesom (1994e). They were first incorporated into Aster by Torrey & Gray (1841), as a subgroup of subg. Ozytripolium. Bentham & Hooker (1873) maintained them as the genus Brachyactis, posi- tioning it next to Erigeron, acknowledging the similarity in floral morphology of these species to Erigeron subg. Trimorpha. Explicitly influenced by Ben- tham’s view, Gray (1873) extracted the species from Aster, though with a caveat regarding the composition of the group (see below). A few years later, however, Gray (1880, 1884) returned them to Aster as subg. Conyzopsis, noting Nesom: Review of Aster taxonomy 207 that the reduced ligules, few disc flowers, and accrescent pappus of Symphy- otrichum (Aster) subulatum (Michx). Nesom “must be held to invalidate the genus Brachyactis,” and aptly observing (see comments below) that within Aster it is “the analogue of the section Trimorphaea in Erigeron” (1880, p. 99). Prior to 1980, other North American botanists who have dealt with the nomenclature or taxonomy of sect. Conyzopsis (e.g., Blake, Wooton & Stand- ley, Ferris, Cronquist) have not provided any comment that would serve as a rationale for treating the group at one rank or another or for placing it in any phylogenetic position. The analysis of Jones & Young (1983) placed sect. Conyzopsis as the sister taxon of subg. Symphyotrichum (see below). But in spite of Jones’s explicitly inclusive view of the composition of Aster, she changed her mind about the rank of sect. Conyzopsis (1984, 1985) and has treated it since then as the distinct genus Brachyactis (e.g., 1992). In justification of this, she provided only the suggestion that these species may have a strong Old World connection. Sect. Conyzopsis (= Brachyactis s. str.) is briefly characterized as follows: (1) annuals usually from a taproot; (2) leaves non-clasping; (3) capitulescence narrowly paniculate, sometimes nearly columnar; (4) phyllaries evenly folia- ceous and of subequal length; (5) disc corollas narrowly tubular and short- lobed; (6) pistillate flowers in ca. 2-4 series in a broad outer zone, more nu- merous than the disc flowers; (7) ligules absent or rudimentary to filiform and short; (8) achenes eglandular, narrowly oblong, flattened, and 2(-4)-nerved; and (9) pappus bristles in 2 series of equal length, conspicuously lengthening (accrescent) with achene maturation. All chromosome numbers reported for these three species have been z=7 (Houle & Brouillet 1985). Semple & Brouillet made two observations regarding their positioning of “sect. Brachyactis” (1980b, p. 1037): “Karyotypically it could easily be derived from some member of sect. Dumosz” (= subg. Symphyot:tchum in the present account, all z=8); and (1980a, p. 1019) “The phyllaries of Aster brachyactis are like those of sect. Dumosi, subsect. Foliacet” (= sect. Occtdentales in the present account). Dr. Brouillet has pointed out (pers. comm.) that he regards similarities in habitat, leaf morphology, and involucra]l morphology between sect. Conyzopsis and Symphyotrichum spathulatum (Lindl.) Nesom (= A. oc- cidentalis [Nutt.)] Torr. & Gray) (and other z=8 species closely related to the latter) to be indicative of their immediate common ancestry, especially in view of the similar NOR chromosome morphology (euaster type). My observations are in agreement. Additionally, S. spathulatum most commonly produces a short, fibrous-rooted rhizome, but there is a distinct tendency in this species for condensation of the rhizome and the corresponding production of a tap- root, bringing this aspect of its habit very close to that of sect. Conyzopsis. In this interpretation of relationship, which is accepted here, the distinctive mor- phology of sect. Conyzopsis reflects a suite of specialized features (the highly reduced floral morphology probably connected with autogamy) derived from 208 PHYVYTOLGVGIA volume 77(3):141-297 September 1994 ancestral states in z=8 ancestors similar to species of sect. Occidentales. The distinction of sect. Conyzopsis as a highly autapomorphic and strongly geneti- cally isolated group within subg. Symphyotrichum is unique, and on a phenetic basis the group might justifiably be treated as a separate genus, but not for the reason that Jones (1984, 1985) has recently suggested. In the analysis by Jones & Young (1983), the phyletic connection between sect. Conyzopsis and subg. Symphyotrichum is provided by four characters: stem pubescence in lines; capitulescence typically ample, much-branched, and more or less diffuse; phyllary apex with a scarious rim; and base chromosome number z=8 or z=7. The assumption that the two chromosome numbers are homologous is supported by the observation that both have NOR chromosomes of the same morphology. Despite their assertion (p. 82) that subg. Symphy- otrichum and sect. Conyzopsis are “separated on the cladogram by only one homoplasious synapomorphy” (leaf nervation, character 8), the latter is the only taxon in their analysis besides Erigeron (the outgroup) scored as having tay flowers in several series (character 25). Further, sect. Conyzopsis (and not subg. Symphyotrichum) is one of the few taxa in their analysis (as scored by them) to share with the outgroup “phyllaries with a chlorophyllous areole forming a band of more or less uniform width that extends from base to apex” (character 14). In my observations, the 2-seriate pappus of sect. Conyzopsis appears to be distinct within Symphyotrichum — the pappus of all other species of the genus, as well as its closest generic relatives (Psilactis, Almutaster, Canadanthus), is 1-seriate or nearly so. A multiseriate pappus is primitive within the Asterinae, but in the phyletic interpretation here, the 2-seriate pappus of sect. Conyzopsis apparently has been re-elaborated from the l-seriate condition of its closest relatives. The suite of floral features that makes sect. Conyzopsis immediately dis- tinctive is shared with other Asterean genera only distantly related to Symphy- otrichum or the Asterinae. Trimorphic flowers have been developed in Asian genus Nannoglottis, which has been positioned in the Solidagininae (Nesom 1994e; Ling & Chen 1965). Annual duration, numerous pistillate flowers in a broad outer zone of ca. 2-4 series, ligules reduced or absent, an accrescent pappus, and flattened, 2-nerved achenes are found in Psychrogeton - Asterinae (Grierson 1967, 1982), Laennecia - Podocominae (Nesom 1990a), some species of Conyza (Nesom 1990b) and Erigeron subg. Trimorpha - Conyzinae (Nesom 1989c, 1994e). All of these have been treated in the past as close associates, relatives, or subgroups of Erigeron, but the similarities in floral and capitular morphology among these genera, as they are placed in different subtribes, are evolutionarily convergent. The species of the Himalayas and central Asia that have been identified as Brachyactis remain taxonomically problematic. Asa Gray (1873) noted that Brachyactis as a genus (sensu Bentham 1873) probably is biphyletic. The Nesom: Review of Aster taxonomy 209 Asian plants produce “broader and flat achenia with prominent marginal ribs, and a pappus of two distinct sorts of bristles, those of the outer set not longer than the width of the achenium” (Gray 1873, p. 648). Further, achenes of the Asian species commonly are glandular on the faces near the apex, their herbage is sessile-glandular, and their base chromosome number is z=9 (Podlech & Dieterle 1969; Mehra & Remanandan 1969, 1974). In this set of features, as well as their geographical distribution, they fit comfortably among the Old World genera of subtribe Asterinae, and it is clear that they are phyletically distant from Symphyotrichum sect. Conyzopsis (see preceding comments on Asian “Brachyactis” in the present treatment). Section Ozytripolium Sect. Ozytripolium has been known as Aster subg. Ozytripolium (DC.) Torr. & Gray, but Nuttall’s name at the subgeneric rank (subg. Astropoltum) pre- ceded that of Torrey & Gray (see Appendix II). Sect. Orytripolium has been recently reviewed by Sundberg (1986), who restricted it to three American species: Aster subulatus Michx. (with five varieties, each of these treated here at species rank), A. potosinus A. Gray, and A. tenutfolius L. (with two vari- eties). These have a base chromosome number of z=5 and commonly grow in damp or marshy habitats. Reports of a chromosome number of n=9 for A. subulatus from eastern Asia (Lee 1970; Huziwara 1958; Peng & Hsu 1977, 1978) need to be reviewed. The Ozytripolium species were taxonomically formalized as a group first by de Candolle (1836), who divided the genus Tripoliur: into two groups, a monotypic sect. Tripolium (T. pannonicum = Aster tripchum, see comments above) and sect. Ozytripolium (T. subulatum (L.) Nees, the type). In the cladistic analysis of Aster by Jones & Young (1983), Aster tripolium (z=9) and sect. Orytripolium were placed within a monophyletic group that also included the distantly related Aster spinosus (= Chloracantha spinosa (Benth.) Nesom, z=9). As discussed above, however, the monotypic, Old World genus Tripolium is more closely related to typical Aster and some of its Old World relatives and is without an intimate relationship to any North American species. Almutaster (Aster) pauctflorus was treated by Jones (1980a) within subg. Ozytripolium, but it was excluded from the subsequent phyletic analysis by Jones & Young because they hypothesized it to be an allopolyploid. Sundberg (1986) excluded South American species from his concept of Aster subg. Ozytripolium, but Jones & Lowry (1986) examined the type of Aster regnellii Baker in Mart. and noted that it is related to A. subulatus. I agree that A. regnellii belongs with sect. Ozytripolium and further note that this group comprises at least eleven species, most of these endemic to east- ern and southeastern South America in habitats of relatively low to moderate 210 PHYTOL OGIrA volume 77(3):141-297 September 1994 elevations. In fact, many of the autochthonous South American species that have persisted within the genus Aster in recent taxonomic treatments belong to sect. Orytripolium; the nomenclature remains unsettled and a few species of this group perhaps are yet undescribed. Some of the better known indigenous species of South American sect. Ozytripolium (treated here within Symphy- otrichum) are S. patagonicum (Cabrera) Nesom, S. peteroanum (Phil.) Nesom, and S. vahli (Gaud.) Nesom. The species of sect. Ozytripohum from Central America and southern North America represent the northernmost elements of this group. Symphyotrichum subulatum (or segregates) and S. squamatum (Spreng.) Nesom are cosmopolitan weeds. As in the North American species of sect. Ozrytripolium, the South Ameri- can ones include taprooted annuals as well as rhizomatous perennials; all are glabrous or with greatly reduced vestiture, the leaves are more or less thick- ened, linear to oblanceolate, parallel-veined, and commonly with scabrous mar- gins, the phyllaries usually with a distinctly delimited, basally attenuate apical patch, the disc corollas are narrowly tubular with deltate, erect lobes, and the ligules are sometimes reduced in length but usually strongly coiling. The ach- enes are 3-5(-6)-nerved and commonly are flattened; the pappus is 1-seriate and in some species (Symphyotrichum vahlit, S. regnellii (Baker) Nesom, S. squamatum) tends to be noticeably accrescent. Similar features also occur in Symphyotrichum sect. Dumosi, where there is a strong tendency for glabrous leaves and stems, non-clasping, narrowly lanceolate leaves, the upper cauline becoming merely bracteate and grading into phyllaries, a loosely paniculate capitulescence, phyllaries with a basally attenuate apical patch, and achenes of similarly reduced size and nervation. In the view here, sect. Orytripolium is included with Symphyotrichum as a specialized member, perhaps derived from ancestors that would be placed in sect. Dumosi. Morphological similar- ities that have been observed between sect. Ozytripolium and Eurybia sect. Heleastrum are considered to be evolutionarily parallel. Cuatrecasas (1969) transferred the South American Aster vahlii (Gaud.) Hook. & Arn. to the genus Oritrophium, although he acknowledged that the record of this species in Colombia was based on scanty material needing fur- ther investigation. This species figured in the delimitation of the geographic range of Oritrophium (Nesom 1992a), but in my recent examination of A. vahli: from over its range, it is clear that it belongs within Symphyotrichum sect. Ozytripoltum rather than Oritrophium. Most conspicuously, the plants are essentially glabrous and the disc flowers produce fertile ovaries, both fea- tures anomalous in Oritrophium. Further, the only report of a chromosome number for any of the indigenous South American Symphyotrichum species other than S. squamatum has been for S. vahlii as n=12 (Moore 1981). This number almost certainly is based on z=6 and is more likely to be homologous with the z=5 previously reported for sect. Ozytripolium than the z=9 known for Oritrophium (Nesom 1992a). With the exclusion of S. vahlii, Oritrophium Nesom: Review of Aster taxonomy rail becomes better defined in geographic range and ecology as essentially a north- ern Andean phylad of high-elevation habitats. Cuatrecasas (pers. comm. 1993) has acknowledged that what he identified as S. vahliz in Colombia is instead a long-stemmed form of O. limnophilum (Sch.-Bip.) Cuatr. a. Relationships of sect. Orytripolium Sundberg (1986) noted that South American plants identified as Aster reg- nellii and A. squamatus (Spreng.) Hieron. in Sod. var. graminifolius (Spreng. ) Hieron. in Sod. appear to be intermediate between [Symphyotrichum] sect. Ozytripolium and [Eurybia] sect. Heleastrum. Jones (1982) and Jones & Young (1983a) suggested that Eurybia chapmanii (z=7, subg. Heleastrum) may have originated in a cross involving an z=9 plant of subg. Heleastrum and an z=5 one of sect. Ozytripolium. An hypothesis of immediate common ancestry for subg. Heleastrum and [Symphyotrichum] subg. Virgulus was based on obser- vations of apparently specialized similarities between these two taxa (Jones & Young 1983) and Jones’s early conclusion that the base chromosome number of both groups was z=5. Another indication of the evolutionary affinities of sect. Ozytripolium was discovered by Sundberg (1986) in a population of asters from northern Oaxaca, México. These plants are closest in morphology to Symphyotrichum potosinum (A. Gray) Nesom (z=5, sect. Ozytripolium), but they have a chromosome number of n=13 and morphological features that suggest they originated in a hybrid cross between S. potosinum and S. bullatum (Klatt) Nesom (z=8, subg. Symphyotrichum sect. Dumosi), which occurs in the same region, al- though the two putative parental taxa are now completely allopatric. In an experimental cross between these n=13 plants and S. potvsinum from Arizona, Sundberg produced fertile progeny nearly identical to the n=13 plants but with a chromosome number of n=18. The alloploid origin of these z=13 plants is biologically and taxonomically analogous to that of S. ascendens (Lindl.) Ne- som (discussed above) and provides evidence of a close relationship between sect. Orytripokum and other groups of Symphyotrichum. Symphyotrichum bullatum is one of the two southernmost species of subg. Symphyotrichum in geographic distribution (the other is S. schaffneri {S.D. Sundb. & A.G. Jones] Nesom) and thus relatively close to the geographic cen- ter of diversity for sect. Ozytripolium. Symphyotrichum bullatum is similar to plants of sect. Ozytripolium in overall appearance, especially in its narrowly lanceolate, nearly glabrous leaves, but its stem hairs in lines, chromosome number of n=8 (Anderson et al. 1974; Strother 1983), and other features in- dicate that its placement in sect. Dumost is reasonable (Jones 1980; Jones & Young 1983). Sundberg (1986) also noted the possible occurrence of hy- bridization between S. bullatum and S. schaffneri, which is also a member of 212 PHY TODOG?raA volume 77(3):141-297 September 1994 sect. Dumosi. On the stems of S. potosinum itself, the hairs are produced in vertical lines, especially just above the nodes, a feature probably indicative of common ancestry of S. potosinum and sect. Dumost. Both S. potosinum and S. bullatum produce a loosely corymboid capitulescence. It is remarkable that Cronquist (1980) hypothesized that S. stmmondsiz (Small) Nesom may be a hybrid between S. bracez (Britton ez Small) Nesom (sect. Ozytripolium) and S. dumosum (L.) Nesom (sect. Dumosz), a situation analogous to the relationship postulated by Sundberg between S. potosinum and S. bullatum. Whatever the evolutionary situation may be, it is clear that the morphological difference between sect. Orytripolium and sect. Dumosz is slight. Semple & Brouillet (1980a) postulated that a close relationship exists be- tween Symphyotrichum sects. Ozytripolium (the z=5 members) and subg. Vir- gulus, a view apparently dominated by consideration of their similarity in chro- mosome number (the NOR chromosome morphology is different). They ob- served the logical necessity (in their system) of recognizing sect. Ozytripolium at generic rank, coordinate with Virgulus (a separate genus, in their interpre- tation), but they have deferred from excluding these species from Asters. lat. “for nomenclatural reasons” (Semple et al. 1989). Such reluctance, however, almost certainly reflects a perception of the biological complexity of the situ- ation as well as possible problems associated with the nomenclature. In fact, species of sect. Orytripolium have already been treated at generic rank, first by Rafinesque (1837, as Mesoligus) and much later by Tamamschyan (1959, as Conyzanthus). b. The status of Aster subulatus s. lat. Sundberg (1986, yet formally unpublished) treated Symphyotrichum sub- ulatum as a polymorphic species of Aster with five varieties (their names as accepted here in parenthesis): var. subulatus (= S. subulatum), var. elonga- tus Bosserd. (= S. bahamense [Britton] Nesom), var. igulatus Shinners (= S. divaricatum [Nutt.] Nesom), var. parviflorus Nees (= S. expansum [Poepp. ez Spreng.] Nesom), and var. sandwicensis (A. Gray) A.G. Jones (= S. squa- matum). Sundberg’s taxonomy emphasized the obvious close similarity and relationship among these taxa (as compared to the other two species of sect. Ozytripolhum that he recognized), a hypothesis of hybrid origin for two of them, and the occurrence of intermediates in three instances (see below) among the taxa involved. In contrast, each of these five is treated here as a species, a morphologically distinct and reproductively isolated entity with a distinct geo- graphic range. The present discussion relies in significant part on information from Sundberg’s dissertation. In their native (New World) ranges, the geographic distribution of each of these five taxa is discrete, each almost completely allopatric with the others’ Nesom: Review of Aster taxonomy 213 (Sundberg 1986). In those with partially contiguous ranges, their close ap- proach to each other with relatively few intermediates in relatively small areas is as notable as the observation that intermediates do occur. While acknowl- edging that the morphological differences among them are relatively small, the taxa are discrete and readily distinguishable. Further, Symphyotrichum subu- latum and S. expansum are self-compatible (and presumably autogamous) with correspondingly reduced floral morphology; the other taxa are outcrossers. Symphyotrichum squamatum and S. bahamense are tetraploids (n=10), while the other taxa are diploids. Naturally occurring intermediates have been noted by Sundberg to occur between (1) Symphyotrichum bahamense and S. subulatum, (2) S. bahamense and S. ezpansum, and (3) S. divaricatum and S. ezpansum. The hybrids re- sulting from crosses between tetraploid S. bahamense and the two diploids S. subulatum and S. ezpansum are triploid and almost completely sterile. Sund- berg also has noted (p. 63) that “Artificial hybrids produced in the greenhouse among these [five] varieties [in all combinations] are highly sterile.” The geographic ranges of Symphyotrichum divaricatum and S. ezpansum are intermittently contiguous roughly along the Texas-Meéxico border and into New Mexico. Although Sundberg noted that plants intermediate in ligule length occur in trans-Pecos Texas, New Mexico, and northeastern Chihuahua, these apparently are uncommon, and the two recently have been collected at the same locality in southwest Texas without evidence of intermediacy (Pre- sidio Co., Worthington 22696 and 22697 [TEX,UTEP]). These two taxa differ in capitular and floral morphology and are distinctly different in habit as well. The ranges of S. divaricatum and S. subulatum approach each other in Louisiana, but the latter species is restricted to coastal marshes, and there is no indication that it occurs together or intergrades at all with S. divaricatum. On the northern margin of its range, S. bahamense appears to form interme- diates with S. subulatum, and it forms intermediates with S. erpansum on its southern margin. Such intermediates do not appear to be common, and the F,’s are triploid. A similar view with respect to the taxonomy of Symphyotrichum tenutfoltum (L.) Nesom and S. bracei is followed here. These taxa were maintained as vari- eties of a single species by Sundberg but have been kept as separate species by others (e.g., Cronquist 1980; Wunderlin 1982), with the acknowledgment that some apparent intermediates occur even though the two taxa are otherwise generally distinct over most of their ranges. Whether a broader or narrower species concept is adopted, a new generic nomenclature must be applied to these Oxytripolioid taxa. The narrower interpretation followed here is the most reasonable, I believe, but which will ultimately prove more reflective of the biological situation remains to be decided by further study. 214 PHYTOLOGIA volume 77(3):141-297 September 1994 B. Subgenus Virgulus Subg. Virgulus comprises a variable but evidently monophyletic group of species, as recognized by both Jones (1980a) and Semple & Brouillet (1980a), although there have been varying interpretations regarding patterns of simi- larity (and implied relationships) among its constituent species (Jones 1980a; Semple & Brouillet 1980a; Nesom 1989b). It is variable in vegetative and capit- ular morphology but the species have a specialized base chromosome number of z=5 and a distinctive NOR chromosome morphology. The group is briefly characterized as follows: leaves mostly oblong, epetiolate, and clasping or sub- clasping, and except for one group of four species (sect. Concolores), the stems, leaves, and phyllaries are stipitate-glandular; capitulescence open-paniculate to terminal and corymbiform (mostly in Symphyotrichum novae-angliae); phyl- laries usually with a distinctly delimited, green apical patch, varying from basally truncate to attenuate; disc corollas narrowly tubular; achenes sub- terete. short-cylindric to obovate, (1.2-)2.5-3.5(-4.0) mm long, with (5-)6-10(- 11) longitudinal nerves, producing a 1-seriate pappus. The achenes usually are densely strigose to sericeous but some species (e.g., 5. concolor [L.| Nesom) produce glabrous achenes. Subg. Virgulus differs from subg. Symphyotrichum in a combination of characters: glandular vestiture, non-glandular stem hairs generally distributed (not in lines), subterete, multinerved achenes, phyllar- ies with a tendency for basally truncate apical patches, and its chromosome number and karyotype. The rationale for the treatment of Virgulus at generic rank was primarily based on its distinction as a natural group (including «he distinctive mor- phology of the NOR chromosomes), the lack of an unequivocal hypothesis of relationship between it and any other species within the rest of Aster, and the assumption by Semple & Brouillet (1980b) that within the Astereae the z=5 groups are distantly related to the z=9/8 groups. For example (p. 1011): “Our primary reasons {for segregating subg. Virgulus as a genus] were based on morphology, but our interpretation of phylogeny in the Tribe Astereae was also critical.” And “On the basis of the cytological evidence alone (Semple & Brouillet, 1980b), we would be reluctant to assign the z=5 species of {subg. Virgulus| to the z=9 genus Aster.” The claim by Semple & Brouillet (1980a) that subg. Virgulus is more closely related to Astereae outside of Aster was accompanied only by the following statement (p. 1010): “Its affinities are with such z=5 genera as Machaeranthera, Psilactis, Astranthium and more distantly with Chrysopsis sensu Semple, Xanthisma, Bradburia and the z=6 genera Xy- lorhiza, Prionopsis, Grindelia and Pyrrocoma.” There has been no morpho- logical evidence adduced that might ally subg. Virgulus with any other genus outside of the traditional Aster alliance. In contrast, preliminary molecular — studies by Suh (1989), Morgan (1990), and Morgan & Simpson (1992), as well as other morphological and genetic evidence (see below), suggest that subg. | Nesom: Review of Aster taxonomy 215 Virgulus is closely related to New World groups generally treated as Aster and that subg. Virgulus is not closely related to any of the genera in the Machaer- anthera lineage (r=6/5) or any of the others listed by Semple & Brouillet. This is confirmed in a morphologically based survey and classification of the entire tribe (Nesom 1994e). Almost all of the taxa placed in subg. Virgulus by Semple & Brouillet have a chromosome number based on z=5 (or reduced to z=4; but two “virguloid” species have been reported as r=9. Aster carolintianus Walt. does not be- long with subg. Virgulus (see comments above under Ampelaster), although its status has not been reevaluated by Semple. Nor has the chromosome num- ber and mode of origin of A. gypsophilus B.L. Turner (Turner 1974) been accounted for. Symphyotrichum (Aster) gypsophilum (B.L. Turner) Nesom is similar in habit, vegetative morphology, and floral and fruit morphology to a group of primarily Mexican species with a known chromosome number of z=5, including S. moranense (Kunth) Nesom and S. trilineatum (Sch.-Bip. ez Klatt) Nesom. Symphyotrichum oblongifolium (Nutt.) Nesom (z=5) appears to be closely related to these (Nesom 1989b and included references) and its NOR chromosome morphology has been determined to be virguloid. The pre- dicted base chromosome number of S. gypsophilum would be z=5 (with n=10 as tetraploid) rather than z=9; an intensive effort in 1993 to relocate plants of this rare species for a chromosomal study was unsuccessful. A hypothesis for the complete separation of Virgulus from z=9/8 phylads is contradicted by its morphological similarity to plants of Symphyotrichum s. str. and by the existence of natural hybrids between plants of Symphyotrichum subg. Symphyotrichum (z=8) and subg. Virgulus (z=5). Symphyotrichum as- cendens, a distinctive and common species of the western United States, has diploid, tetraploid, and octoploid populations based on z=13, an amphiploid condition resulting from a hybrid cross between S. spathulatum (z=8, subg. Symphyotrichum) and S. falcatum (Lindl.) Nesom (z=5, subg. Virgulus) (Jones 1977; Allen et.al. 1983; Dean & Chambers 1983; Allen 1985). Symphyotrichum ascendens backcrosses with S. spathulatum and forms natural, highly fertile hy- brids with at least three other z=8 species of the S. spathulatum complex (Allen 1985). Symphyotrichum defoliatum (Parish) Nesom (= Aster bernardinus Hall; n=18), another species closely similar to S. spathulatum, is a stabilized am- phiploid formed as a backcross between S. ascendens and S. falcatum (Allen 1986). The two hybrid species are more or less intermediate in habit and ca- pitulescence between the diploid parental species; they are more similar to the virguloid line in their vestiture of generally distributed trichomes and multi- nerved, subterete achenes, but they do not produce the glandular trichomes characteristic of the virguloid parents. In an alternative resolution to the taxonomic problem associated with Sym- phyotrichum ascendens, S. defoliatum, and their backcrosses to other species, Semple (1985) placed these two species into the separate genus Virgulaster, 216 PHYTOLOGIA volume 77(3):141-297 September 1994 in parallel with the maintenance of Virgulus as a genus separate from Aster. He simultaneously proposed a new category for them within Aster (“subg. Ascendentes”). In the present system, these two species are treated within Symphyotrichum sect. Ascendentes (see Appendix II), near other species with which they have usually been placed on the basis of morphology, and with the recognition that their genomes include divergent elements. The introgressants are variously identified, according to their morphologically closest parent. XIII. Incertae sedis - Chloracantha The variable and widespread North American species Aster spinosus re- ceived a name as Erigeron (E. ortegae S.F. Blake) but it was recently seg- regated as the monotypic genus Chloracantha (Nesom et al. 1991; Sundberg 1991). The plants are remarkably similar in habit to Boltonia (Asterinae), but their relatively small (1.5-3.5 mm long), terete achenes with 5(-6) nerves are more like those of specialized taxa of Symphyotrichum and some Solidagininae than any species closely related to Aster s. str. Several features of Chlo- racantha, however, appear to eliminate it from inclusion among the groups of the Eurybian lineage (phyllaries 3-5 nerved with rounded apices, unkeeled, and herbaceous without an apical patch, deltate and papillate style branch appendages, disc corollas with orange resin ducts accompanying the veins, remaining yellow at maturity, and pappus of 1-2 series of equal length bris- tles, sometimes with a few short, outer setae). Other distinctive features of Chloracantha are summarized as follows: rhizomatous, completely glabrous perennials, usually restricted to wet habitats, the stems spiny and chlorophyl- lous but becoming internally woody and producing true axillary resting buds with bud scales, the leaves early deciduous, leaving only the stems at flowering, and heads small, terminal and solitary, scattered in a diffuse panicle. The remarkable morphological specializations of Chioracantha do not pro- vide evidence of a close relationship with any other species. In a preliminary interpretation of data from chloroplast DNA studies, however, Nesom et al. (1991) ventured that Chloracantha (as well as Boltonia) are closely related to each other and that their phylogenetic position lies near the base of the Chrysopsidinae. This is a problematic interpretation, however, because the samples for molecular study by Morgan & Suh did not include species appar- ently among the primitive stock of the group recognized here as the Asterinae, and the possibility seems strong that Chloracantha early diverged from stock close to the base of all of the Northern Hemisphere subtribes (see further comments above). Nesom: Review of Aster taxonomy 217 XIV. Incertae sedis - Tonestus Tonestus is briefly characterized as follows: perennial herbs arising from thick, woody caudex branches (7. kingit apparently taprooted; T. lyallii (A. Gray) A. Nelson with a system of slender rhizomes); basal leaves commonly persistent, but the stems leafy, the cauline leaves grading into phyllaries; leaves 3-veined from the base, obovate, subclasping but not auriculate, the margins often toothed-spinulose; stems, leaves, and phyllaries distinctly and densely pilose-glandular with long, vitreous, biseriate, gland-tipped hairs (Type C tri- chomes); heads sometimes few and loosely corymboid but most commonly reduced to one; phyllaries in 3-4 series mostly of equal length, at least the outer foliaceous; rays yellow, white, or absent; disc corollas narrowly tubular, the tube ca. 30% of the corolla length, opening into a slightly broader limb; achenes narrowly oblong in outline, terete to somewhat compressed, 5-nerved, 5-8 nerved, or 8-12 nerved (see below), glabrous to strigose; pappus mostly 2- seriate (J. kingit 1-seriate; T. pygmaeus (Torr. & Gray) A. Nelson often with a short outer series), the bristles apically attenuate; base chromosome number, z=9, Tonestus as constituted here is variable in most of the features that might be used in its definition: habit, vestiture, leaf margins, degree of cauline leaf development, the nature of the capitulescence, phyllary morphology, style ap- pendage morphology, ray color, and achene and pappus morphology. Like Eurybia (below), however, the relatively few species of Tonestus appear to be “interlocking” in their overlapping pattern of variability, and it is difficult to pry the group apart, although the possibility remains that the genus, as con- sidered here, is polyphyletic. Tonestus kingit, T. aberrans (A. Nelson) Nesom & Morgan, and T. graniticus (Tiehm & Schulz) Nesom & Morgan appear to form a distinctive subgroup on the basis of the following features: (1) keeled phyllaries that tend to be graduated in length (especially in T. graniticus); (2) hairy disc style appendages (in T. kingit and T. aberrans, as well as T. exzim- tus (H.M. Hall) A. Nelson & Macbr., but not 7. graniticus) vs. appendages closely papillate in the other species; and (3) 5-nerved achenes (5-8-nerved in T. graniticus) vs. 8-12-nerved in the other species. Tonestus kingii produces white rays, while T. aberrans and T. graniticus are rayless; the other species are yellow-rayed (or rayless in T. alpinus [Anderson & Goodrich] Nesom & Morgan). Tonestus lyallii (the generitype), with entire leaves and a system of relatively slender rhizomes, stands alone in habit among the other species, but its dense vestiture of long-stipitate glands is modal in the genus. Tonestus pygmaeus also produces entire leaves but is distinctive in its lack of glands. Haplopappus microcephalus Cronq. was treated within Tonestus by Nesom & Morgan (1990) but is better placed in the vicinity of the genus Petradoria of the Solidagininae. The species will be formally treated by Gary Baird, 218 PHYTOLOGIA volume 77(3):141-297 September 1994 who includes it along with Petradorta within Chrysothamnus in a forthcoming review of the latter genus. Tonestus has been placed close to Solidago and its relatives in analyses based on DNA data (Morgan & Simpson 1993; T. pygmaeus the sampled species), and I have treated Tonestus within the Solidagininae (Nesom 1993c), noting that it occupies an isolated position there but that it has similari- ties (particularly in vestiture and foliaceous phyllaries) to Oreochrysum and Nannoglottis, the latter two genera hypothesized to be closely related between themselves and placed near the phylogenetic base of the Solidagininae. DNA sampling of Astereae, however, has been highly incomplete with respect to pu- tatively basal taxa of the Solidagininae and Asterinae, and in a broader mor- phological context, Tonestus also appears to be similar to genera placed here in the Asterinae although it would be the only genus there with yellow-rayed species. It clearly lies outside the Machaerantherinae and Chrysopsidinae. Most features of Tonestus are ambiguous in regard to its possible placement in the Asterinae or Solidagininae (e.g., ray color, style branch morphology, achene and pappus morphology), but the glandular vestiture, subclasping, spinulose leaves, and foliaceous, equal-length phyllaries are more common in the Asterinae, particularly among the taxa of Eurybia subg. Oreostemma, as treated here. The position of Tonestus is uncertain, but it may have origi- nated from stock very similar to the ancestors of both the Solidagininae and Asterinae. BIOGEOGRAPHY OF ASTER SENSU LATO Genera, species groups, and species disjunct between eastern North Amer- ica and southeastern Asia have long been well-known (e.g., Gray 1859; Li 1952; Graham 1972; Zhengyi 1983; Tiffney 1985b). Other taxa are disjunct between Asia and western North America, yet others have a tricentric pattern with populations in Asia and both areas of North America, and there are various other permutations of these patterns (Ying 1983). A few of these taxa, espe- cially those with representation in eastern North America, have an additional series of disjunct populations in México or Central America. Asteraceae have seldom been mentioned or included in such accounts, and Zhengyi’s inclusion of Brachyactis in a summary of this nature (1983) is problematic from several standpoints (see discussion above of Symphyotrichum sect. Conyzopsis). In contrast, Tiffney (1985a) noted that nineteen genera of Asteraceae are rep- resented both in Asia and eastern North America, although only a few of these have disjunct species, species pairs, or species groups. Doellingeria (Ne- som 1993f), Solidago (Nesom 1993c), Eupatorium (King & Robinson 1970), Cacalia, and Prenanthes are examples that belong with the latter group. Nesom: Review of Aster taxonomy 219 The evolutionary radiation and geographic dispersion of Doellingeria and Solidago probably were roughly contemporaneous, as the phyletic position of both genera is hypothesized to lie near the divergence of the Solidagininae (sensu Nesom 1993c) and Asterinae. The more primitive species of Solidago (sect. Solidago) occur primarily in eastern North America and southeastern Asia, with the advanced groups (sect. Unilaterales D. Don) restricted to the New World. The species of Doellingeria sect. Doellingeria are divided between eastern North America and southeastern Asia. If the relationship between the American Boltonia (Asterinae) and the genera of the Asian Kaltmeris group is as close as postulated in the present study, this provides an analogous example of such a relictual pattern of disjunction within the Astereae. Further, as noted above, the pattern of relationship of Eucephalus and Oclemena to Old World Aster is not clear, and these may yet prove to be closely but independently related. Finally, several Old World groups presently maintained within Aster (see discussion of “Problematic species”) may prove to be more closely related to genera of American Asterinae than to Asian ones. An early Cenozoic “boreotropical flora” included many temperate decid- uous forest species with patterns of distribution similar to Doellingeria, Sol- tdago, and the Kalimeris group (including Boltonia), and these Asteraceae can reasonably be regarded as members of the same flora, which apparently extended from southeast Asia westward along the Tethys Seaway into Eu- rope, Greenland, and eastern North America (Taylor 1990). The Asian-eastern American connection apparently was made across a North Atlantic route that, while often loosely connected, was available for overland dispersal in the early Cenozoic (Paleocene into the Eocene and perhaps up to early Miocene: e.g., Hamilton 1983; McKenna 1983; Tiffney 1985b; Taylor 1990). The boreotrop- ical flora reached its maximum extent by early Eocene (Tiffney 1985b), and Hsu (1983, p. 506) observed that paleobotanical evidence shows that “after the Eocene Chinese vegetation was rapidly modernized by the loss of the Ameri- can elements.” A north-Pacific (Beringian) land bridge also was open during the Eocene (particularly middle and late Eocene) and apparently facilitated the migration of deciduous forest species between western North America and Asia (Wolfe 1985; Tiffney 1985b). According to Wolfe (1987, p. 789) “The microthermal vegetation and flora [of the Rocky Mountains] of the Late Cre- taceous and the Paleocene have few similarities to Eocene and later vegetation and flora,” but (p. 792) “the great majority of extant genera of woody mi- crothermal angiosperms had evolved by the end of the Eocene.” The broader nature of the connection of the western North American boreotropical flora to the Eurasian elements, whether solely across the north Pacific or also across the north Atlantic (and thus subsequently across mid-continental North Amer- ica) is not clear. In summary, although palynological evidence has placed the primary diversification of the Compositae in the Miocene (Muller 1981) and Raven & Axelrod (1974) have allowed an origin for the family no earlier than 220 PHYTOLOGIA volume 77(3):141-297 September 1994 Oligocene, biogeographic evidence suggests that taxa of at least two or three Astereaean groups (basal Solidagininae and Asterinae and the Kalimeris group of Asterinae) were already differentiated by the Eocene and dispersed in the Northern Hemisphere of the Old and New Worlds. Among other taxa of strictly New World Asterinae, Oclemena is restricted to eastern North America. Sericocarpus is divided between eastern and west- ern North America. The closely related Eurybia is relatively widespread; the putatively basal taxa are primarily eastern North American, but other species and species groups are primarily western North American. The species of Symphyotrichum subg. Symphyotrichum appear to follow a similar pattern of distribution. Tonestus and Eucephalus, in contrast, are zestricted to western North America. Jonactis is a western genus except for J. linarifolia (L.) E. Greene, which occurs only in eastern North America. . A few North American asters (e.g., Eurybia stbirica and Symphyotrichum [Brachyactis| ciliatum) have distributions from the Rocky Mountains into Alaska and across a Beringian route into Asia. Aster alpinus, which has its closest relatives in Asia, crosses into North America by the same route. It is likely that the dispersion of such species between these two continents was relatively recent, as noted by Mizushima (1972) and Kruckeberg (1983) for other taxa. According to Jones (1977, p. 342), “There is general agreement that the center of origin of Aster proper lies in North America (Huziwara 1958; Raven et al. 1960). The largest number of species and also the highest degree of diver- sity are found in this continent. .... The Old World species belong partly in sections unique to that vast area; in a large part, however, they are derivatives of New World asters.” Semple & Brouillet (1980a, p. 1016) were of essentially the same view: “The genus presumably originated in North America and there- fore all the non-North American groups are derived directly or indirectly from North American groups.” Grierson (1964) deferred from speculating on the area of origin of the Old World species. In the phylogenetic hypothesis pre- sented in the present study, phyletically basal elements of the Asterinae are divided between Eurasia and North America, but a greater concentration of primitive species and species groups remain in North America. Some genera and generic groups from the Asterinae and other subtribes with their center of diversity and apparent center of origin in North America have disjunct but relatively closely related representatives in South America. The southward extensions of Symphyotrichum sect. Ozytripolium and Psilactis into South America, Gutierrezia (Solidagininae) and Grindelia (Machaeran- therinae) into the southern Andes, and Solidago (Solidagininae) into south- eastern South America probably are relatively recent in origin compared to the Asian-American disjunctions of Astereae. The South American Haplopap- pus (Machaerantherinae), an Andean endemic, is closely related to and per- haps conspecific with Hazardia, which is primarily centered in Baja Califor- nia. Noticastrum (Chrysopsidinae), however, is an endemic genus primarily Nesom: Review of Aster taxonomy 221 of southeast-central South America with its closest relatives all North Amer- ican genera. The mode and geological time of dispersal of this array of taxa probably is diverse. CHROMOSOME EVOLUTION IN THE ASTEREAE The systematic treatment of American Asterinae focuses attention on two long-standing cytological problems in the Astereae: the base chromosome num- ber of the tribe, and the apparent close relationships of species with a chro- mosome number of z=9 to those with a number of z=5 or z=4. Resolution of these problems may prove to be part of a more general insight that accounts for the difference between genera of Astereae with a highly conservative base chromosome number of z=9 (e.g., Erigeron, Olearia, Townsendia, Solidago, Heterotheca, Ericameria, Baccharis and all other Baccharidinae, with z=9) and other clearly or hypothetically monophyletic groups where an array of chromosome numbers occurs, particularly those with z=9/8 lowered to z=5 or near it. The hypothesis that z=9 is the primitive state for the Astereae is supported by a significant number of monophyletic groups known with both z=9 and an array of decreasing numbers, together with the preponderance of strictly z=9 groups found in genera of all subtribes of Astereae except the Machaerantheri- nae. Phylogenies produced from molecular evidence, at all taxonomic levels within the tribe, also consistently place z=9 taxa in phylogenetically basal positions. The hypothesis of primitive z=9 in the Astereae has been advanced at least since 1959 (see Jones 1985 for a review). Finally, outside of the New World, across all subtribes of Astereae, genera with base chromosome numbers other than z=9 are rare. In those Old World groups where lower numbers do occur, in almost every case they are clearly derived from an ancestral z=9 (see examples below). Evidence cited against the primitive status of z=9 in the Astereae has been based primarily on a lack of expected intermediate steps in the derivation of z=5 from z=9 (mostly z=7 level, but z=6 and z=8 also are relatively uncom- mon) (Brown 1972; Turner et al. 1961). This argument is countered, however, by an analogous observation: if z=9 is derived as an amphiploid between z=5 and z=4 plants, or between z=5 and z=5 with a subsequent aneuploid decrease of one pair, then such an occurrence has been extremely frequent, and base numbers of z=10 and z=8 (as amphiploids of two z=5’s or two z=4’s) should also be expected and at a much higher frequency than is found. In fact, there are no genera or generic groups of Astereae with a base number of z=10 (with the possible exception of Centipeda) and few with z=8 (see examples below). This also suggests that if z=9 in the Astereae has been derived by a reduction in number from an ancestral z=10 genome, such an event must have occurred 222 PHY TOLOGIA volume 77(3):141-297 September 1994 prior to the inception and evolutionary radiation of the tribe. Further, a large number of the z=9 species of Aster and Solidago have chromosomes that are even-sized and mostly submetacentric, a condition that has been interpreted as primitive in many groups of vascular plants (e.g., Stebbins 1971). Evidence for a base chromosome of z=9 (or z=8), with subsequent ane- _uploid decrease, can be seen in the following Astereaean genera and generic groups with wide variability in base number: Calotis (z=8, to 7,5,4, with evidence for descending aneuploidy: Stace 1978); Brachycome (one section conservative with only z=9; the other section with z=9, to 8,7,6,5,4,3,2, as well as n=10,11,12,13,14,15,16, the latter num- bers variously constituted primarily by amphiploidal crosses between lower numbers: Smith-White et al. 1970; Carter 1978; Watanabe & Short 1992); Felicia (z=9, to 8,6,5: see Grau 1973); Amellus (z=9, to 8,6: see Rommel 1977; Podlech & Dieterle 1969); Symphyotrichum subg. Symphyotrichum (8,7,6: the present summary); Symphyotrichum subg. Virgulus (5,4: the present summary); Psilactis (r=9, to 4,3, although it is not clearly established that the lower numbers are primitive); among the genera of the Townsendia group (z=9, to 5,4,3: Nesom in prep.), including Townsendia, Geissolepis, Astranthium, Dichaetophora, and A- phanostephus; among the genera of the Gutterrezia lineage (z=9, to 5,4, perhaps including z=8: see Nesom 1991c, 1993c); among the genera of the Chrysopsidinae (z=9, to 7,6,5,4: see Nesom 1991b). among genera of the Grangeinae; the genus Centipeda has a chromosome number of n=10; the other genera of the subtribe (see Nesom 1994e) are reported as z=9, there are no other species or genera of Astereae known with a base number of z=10, and it seems most likely that these Centipeda species are tetraploid based on z=5, although an aneuploid increase to z=10 is possible; disparate counts based on z=5 and z=9 are reported within the South Amer- ican genus Hysterionica, but these need to be reinvestigated (see Nesom 1994d for a summary). Nesom: Review of Aster taxonomy 223 There is at least strong circumstantial evidence in the examples above (except the last two) for descending aneuploidy as the primary process of evolutionary change in chromosome number. This reduction in chromosome number appears primarily to involve the redistribution of chromatic material onto fewer chromosomes, with a corresponding loss of centromeres but without a genetic loss (Gottlieb 1981; this process referred to as “meroaneuploidy” by Jackson 1971; Stucky & Jackson 1975). Astereaean genomes of z=5, in partic- ular, have chromosomes with a great amount of resultant structural reorgani- zation, compared to those of z=9. Ascending aneuploidy apparently is rare in the Astereae, but it has been documented within a single species (Watanabe & Smith-White 1987; Jackson 1992; Jackson et al. 1993) and suggested to oc- cur within the genus Astranthium (De Jong 1965). In these cases, the ascent has been from a number less than n=9. Evidence indicates that aneuploid increase also has occurred in polyploid hybrids involving the Old World Aster ageratotdes (Tara 1973) and the American Symphyotrichum (Aster) foliaceum (DC.) Nesom (Allen 1984, 1985). The concentration in North America of genera with low Homi chromosome numbers might be taken as an indication these numbers reflect a pattern of common ancestry, but this is contradicted both by morphological and molec- ular evidence (Nesom 1994e). In almost every case, American genera with base chromosome numbers lower than z=9 are known to be closely related to others with z=9. The greatest number of these low-numbered taxa are among the fifteen genera of the Machaerantherinae (z=6 for the subtribe, reduced to z=5,4,3,2; Morgan & Simpson 1992) and within American Asterinae, where reductions directly from z=9 apparently have occurred independently at least four times: (1) the origin of Symphyotrichum subg. Virgulus (z=5); (2) the origin of Symphyotrichum subg. Symphyotrichum (z=8); (3) the derivation of Eurybia chapmanii (z=7); and (4) the derivation of z=4 species within Psilac- tvs. The only other genera of Astereae with a lowered base chromosome num- ber are the four of the Gutierrezia group of the Solidagininae (probably z=8, reduced to z=5,4; Nesom 1991d, 1993); three within North American Brachy- cominae (z=5, reduced to z=4,3; Nesom in prep.); two of the Monoptilon group within subtribe Feliciinae, i.e., Monoptilon and Chaetopappa (z=8; Ne- som 1992b); and three of the Chrysopsidinae (r=7 and z=5, with reductions to z=6,5,4; Nesom 1991b). The derivation of z=5 and r=4 genomes from z=9 ones might occur by the dissociation of ancestral components of z=5 and z=4, as in polyhaploidy (cf. deWet 1971), but there is little evidence to suggest that z=9 in the Astereae is of amphiploid origin. Semple & Chinnappa (1980a, 1980b) showed that z=9 in Chrysopsis is constituted by alloploidy from an immediate ancestry of z=4 and r=5 parents, which could be interpreted as the reassociation of such putative components. Although the ancestor of Chrysopsis clearly had 224 PHYTOLOGIA volume 77(3):141-297 September 1994 a base chromosome number of z=5, the genus is a member of the subtribe Chrysopsidinae, a phylad hypothesized to have a base of z=9 (Nesom 1991b). The species of Psilactis (see Morgan 1993) constitute the only other group within the Astereae with an array of base chromosome numbers based on 9 and lower numbers completely “disjunct” at z=4 or z=3. Further, the loss of entire sets of chromosomes does not appear possible through ”meroaneuploidy” (Jackson 1975), although this process theoretically might be responsible for the rapid occurrence of such a large gap (t.e., the 9/5 gap) in a succession of contiguous steps. Jackson (1973) has documented a chromosome number reduction by two in the Astereae, and a wide discontinuity (z=10 and z=4) has been reported between two closely related, Central American species within the genus Fletschmannia Sch.-Bip. (Eupatorieae), where z=10 is the base number (see King & Robinson 1987 for comments and references). In view of the probable z=9 ancestry for the Astereae (see above), it seems likely that the correct explanation for the paucity of z=7 (and 8 and 6) has not yet been clearly discerned. It may prove to be related to a relative adaptive advantage accompanying the lower numbers (for comments and references, see Jackson 1971, Stucky & Jackson 1975) or to some other phenomenon, but it seems clear that this “gap” is not merely an artifact of interpretation. NOR chromosome morphology Studies by Semple and colleagues (Semple & Brouillet 1980b; Semple et al. 1983) have provided valuable information regarding the morphology of “satellite” or NOR chromosomes (chromosomes bearing the nucleolar orga- nizer region). They have classified the NOR chromosomes of primarily North American species of Asters. lat. into several different types, depending on the relative lengths of the satellite and proximal portion of the short arm: “prim- itive” type, with the satellite and proximal portion of about the same length; “euaster” type, with the satellite markedly longer than the remainder of the arm; and “virguloid” type, with a minute satellite and correspondingly long arm. The primitive type is characteristic of Doellingeria (including both Amer- ican and Asian species), Oclemena, Eucephalus, Jonactis, and Sericocarpus. A karyotypic description apparently has not been published for the species of Chloracantha and Tonestus. The euaster NOR type might be better termed the “eurybia” type or the “symphyotrichum” type, as it is characteristic of most of the species of those two groups (see caveats below), but Semple et al. (1983) also reported that the generitype of Aster, A. amellus, has primitive type NOR chromosomes. In view of the variability of the chromosomes of the | latter species and conflicting reports regarding its karyotype, a more detailed study is in order. The NOR chromosomes of Symphyotrichum sect. Ozytripolium have acro- centric NOR chromosomes, both the satellite and arm highly reduced in length; 4 z Ai a Nesom: Review of Aster taxonomy 225 these also are unique within the Asterinae and are here termed the “oxytripo- lioid” type. In published photographs of somatic chromosomes of Psilactis (Stucky 1978; Hartman & Lane 1987), the identity and morphology of the NOR chromosome is not immediately apparent, although one of the longest chromosomes of P. asteroides seems to have a small satellite at the end of a much longer arm, approaching the virguloid type (see Stucky 1978, Fig- ures 5 and 7). The NOR morphology of the n=9 species of Pstlactis has not been observed. Almutaster pauciflorus, Eurybia sibirica, Eurybia glauca, and Canadanthus modestus have been reported to have primitive type NOR chromosomes (Semple & Brouillet 1980b; Semple et al. 1983), those of Symphy- otrichum turbinellum to be of “varying morphology.” In view of the phylogeny hypothesized here (Figure 2), it appears that the euaster (“eurybia”) type has been independently evolved at least two times within the genus. Alternatively, it would be necessary to postulate “reversions” to the primitive type in the taxa noted above. The NOR chromosomes of Symphyotrichum subg. Virgulus appear to be markedly different in morphology from all others within the Asterinae, and it is clear that the virguloid NOR morphology is specialized. As noted by Semple & Brouillet (1980b, p. 1035), however, “satellite or NOR chromosomes with morphology like those of [subg. Virgulus] may have evolved independently sev- eral times in the tribe,” and the same possibility must also be admitted for the other NOR types. Karyotypic repatterning is known to occur within numerous monophyletic groups of Astereae, e.g., the genus Astranthium (De Jong 1965) and even within single species, e.g., Aster amellus (Chatterji 1962), Machaer- anthera riparia (Kunth) A.G. Jones (Stucky 1978), and Aster ageratozdes (Ir- ifune 1990). Differences in NOR chromosome morphology clearly are useful in indicating the limits of monophyletic groups, but without an unambiguous interpretation of homologies, karyotypic differences by themselves provide no justification for the determination of taxonomic rank or phylogenetic position of the groups concerned. Huziwara (1967) observed that the chromosomes of Asian and European species of Aster differ from those of American species, the latter generally smaller in size as well as distinct in morphology, but the Asian species have not been included in the recent classification of NOR types. Remarkably, the Old World species consistently produce an NOR morphology (here termed the “Asterinae” type) that differs from all of the New World species: the satellite is much shorter than the remainder of the arm but not reduced to the minute size of the of the virguloid satellite. The Asterinae type has been documented for a range of Old World species among various taxa (see primarily numerous references by Huziwara; also Chatterji 1962), including the following: A. amel- lus, A. amelloides, A. tbericus, and A. maackii (sect. Aster), A. alpinus (sect. Alpigent), A. ageratoides (sect. Ageratoides); A. tataricus and A. fastigiatus (both placed tentatively within Aster and in an uncertain position, see discus- 226 PHYTOLOGIA volume 77(3):141-297 September 1994 sion). The Asterinae NOR type also is found in species that are treated here within genera outside of Asters. str.: Heteropappus, Kalimeris, and Tripolium. ACKNOWLEDGMENTS I thank Billie Turner for his review of the manuscript and long-standing encouragement in this project, Luc Brouillet for his reading and general com- ments on the penultimate version of the manuscript, Verne Grant and Ray Jackson for comments on the discussion of chromosome evolution, John Strother for detailed comments on the nomenclatural status of Eurybia, John Kartesz for a review of the species nomenclature, Mark Mayfield for comments on vari- ous parts of the manuscript, Harold Robinson for many helpful comments and his remarkable insight into the family as a whole, and the staffs of MO and US for their assistance during visits there. Bibliographic help from Barney Lipscomb (BRIT), Denis Kearns (MO), and John Pruski (US) is gratefully ac- knowledged. Matt Turner translated Latin passages from the 1832 monograph by Nees, and Zai-ming Zhao translated various passages of Chinese literature. LITERATURE CITED Allen, G.A. 1984. 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A Cuban endemic: Hysterionica marginata (Asteraceae: Astereae), rather than Aster grisebachit. Phytologia 75:163-165. —___—_. 1993f. Taxonomy of Doellingeria (Asteraceae: Astereae). Phytolo- gia 75:452-462. —__———. 1993g. Comments on the definition of the genus Diplopappus Cass. (Asteraceae: Astereae). Phytologia 75:113-116. . 1994a. Apopyros (Asteraceae: Astereae), a new, monotypic genus from south-central Brazil. Phytologia 76:176-184. 1994b. Jnulopsis synopsis (Asteraceae: Astereae). Phytologia 76:115-124. Peta Nesom: Review of Aster taxonomy 239 . 1994c. Repartition of Mairia (Asteraceae: Astereae). Phytologia 76:85-95. 1994d. Separation of Neja (Asteraceae: Astereae) from Hysterion- ica. Phytologia 76:168-175. . 1994e. Subtribal classification of the Astereae (Asteraceae). Phy- tologia 76:193-274. . 1994f. Hybridization in the tribe Astereae (Asteraceae). Phytologia 77:298-307. Nesom, G.L., L.A. Vorobik, & R.L. Hartman. 1990. The identity of Aster blepharophyllus A. 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Sin. 19:53-66. Pike, R.B. 1970. Evidence for the hybrid status of Aster blake: (Porter) House. Rhodora 72:401-436. Podlech, D. & A. Dieterle. 1969. Chromosomenstudien an afghanischen Pflanzen. Candollea 24:185-243. 240 PHYTOLOGIA volume 77(3):141-297 September 1994 Rafinesque, C.S. 1836 [1837]. Flora Telluriana. Printed for the author by H. Probasco, Philadelphia, Pennsylvania. Raven, P.H., O.T. Solbrig, D.W. Kyhos, & R. Snow. 1960. Chromosome numbers in Compositae. I. Astereae. Amer. J. Bot. 47:124-132. Raven, P.H. & D.I. Axelrod. 1974. Angiosperm biogeography and past con- tinental movement. Ann. Missouri Bot. Gard. 61:539-673. Reveal, J.L. & C.S. Keener. 1981. Virgulus Raf. (1837), an earlier name for Lasallea Greene (1903) (Asteraceae). Taxon 30:648-651. Rommel, A. 1977. Die Gattung Amellus L. (Asteraceae-Astereae) - System- atischer Teil. Mitt. Bot. Staats. Munchen 13:579-728. Semple, J.C. 1982. Observations on morphology and cytology of Aster hemis- phaericus, A. paludosus, and A. chapmanii (Asteraceae) with comments on chromosomal base number and phylogeny of Aster subg. Aster sect. Heleastrum. Syst. Bot. 7:60-70. . 1984. Cytogeographic studies on North American asters. I. Range surveys of Virgulus adnatus, V. concolor, V. georgitanus, V. grandiflorus, V. novae-angliae, V. oblongtfoltus, V. patens, and V. walter. Amer. J. Bot. 71:522-531. . 1985. New names and combinations in Compositae, tribe Astereae. Phytologia 58:429-431. . 1988. Aster brewert: A new combination for a rayless Aster based on Chrysopsis breweri (Compositae: Astereae). Syst. Bot. 13:538-546. . 1992. A geographic summary of chromosome number reports for North American asters and goldenrods (Asteraceae: Astereae). Ann. Missouri Bot. Gard. 79:95-109. Semple, J.C. & L. Brouillet. 1980a. A synopsis of North American Asters: the subgenera, sections and subsections of Aster and Lasallea. Amer. J. 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The floristic relationships of the temperate forest regions of China and the United States. Ann. Missouri Bot. Gard. 70:597-604. Zhang, X. & K. Bremer. 1993. A cladistic analysis of the tribe Astereae (Asteraceae) with notes on their evolution and subtribal classification. Pl. Syst. Evol. 184:259-283. Zhengyi, W. 1983. On the significance of Pacific intercontinental discontinu- ity. Ann. Missouri Bot. Gard. 70:577-590. APPENDIX I. Abbreviated taxonomy of the main groups within Asters. str. The list of species included in each group is not complete, but it provides at least a general, illustrative sketch of the composition of the group and the existing nomenclature. ASTER L., Sp. Pl. 2:872. 1753. Lectotype (Britton & Brown 1913; Hitchcock & Green 1935): Aster amellus L. A. Aster sect. Aster Aster sect. Amelli Nees, Gen. Sp. Aster. 39. 1832. Aster {sect. Aster] ser. Amelli (Nees) Kitamura, J. Jap. Bot. 12:535. 1936. Type: Aster amellus L. Kalimeres Rafin., Fl. Tellur. 2:46. 1836 [1837]. Type: Aster amellus L. Nesom: Review of Aster taxonomy 245 Aster (sect. Aster] ser. Macrocephali Kitam., J. Jap. Bot. 12:533. 1936. Aster sect. Macrocephali (Kitamura) A.G. Jones, Brittonia 32:237. 1980. Type: Aster maacku Regel. INCL: Aster aitchisonii Boiss., A. amellus L., A. amelloides Bess., A. catalaunicus Willk. & Costa, A. ibericus M. Bieb., A. indamellus Grierson, A. laka C.B. Clarke, A. maackit Regel, A. poliothamnus Diels, A. thomsonu C.B. Clarke. B. Aster sect. Alpigeni Nees, Gen. Sp. Aster. 24. 1832. Lectotype (Jones 1980a): Aster alpinus L. Diplactis Rafin., Fl. Tellur. 2:45. 1836 [1837]. Lectotype (designated here): Aster alpinus L- Aster sect. Alpinaster Tamamsch. [nom. illeg.], Fl. URSS 25:104. 1959. (superfluous; no Latin diagnosis] Lectotype: Aster alpinus L. a. Aster subsect. Homochaeta Onno, Bibliot. Bot. 106:7. 1932. Lectotype (designated here): A. alpinus L. To stabilize the usage of this name, the choice of a lectotype follows the precedent by Grierson (1964), who included within subsect. Homochaeta a group of Himalayan species closely related to A. alpinus. Aster (sect. Alpigeni subsect. Homochaeta] subser. Alpini (Rydb.) Onno, Bibliot. Bot. 106:7. 1932. Aster sp.-group Alpini Rydb., Fl. Rocky Mts. 880. 1922. Type: Aster alpinus L. Aster sect. Alpigeni ser. Salwinenses Ling [nom. illeg.|, Fl. Reip. Pop. Sin. 217. 1985. {no Latin diagnosis]. Type: Aster salwinensis Onno. INCL: Aster alpinus L., A. barbellatus Grierson, A. btetit Franch., A. heliopsis Grierson, A. himalaicus C.B. Clarke, A. ionoglossus Ling, A. kor- shinskyt Tamamsch., A. neo-elegans Grierson, A. oreophilus Franch., A. pyre- naeus Desf. er DC., A. retusus Ludlow, A. salwinensts Onno, A. serpenti- montanus Tamamsch., A. spathulifolius Maxim., A. stracheyt J.D. Hook., A. tolmatschevii Tamamsch., A. tricephalus C.B. Clarke. 246 PHYTOLOGIA volume 77(3):141-297 September 1994 Aster {sect. Alpigent subsect. Homochaeta] ser. Macrochaeti: Onno, Bibliot. Bot. 106:7. 1932. Lectotype (designated here), Aster glabriusculus (Nutt.) Onno = Xylorhiza glabriuscula Nutt. (the group becoming a synonym of the North American genus Xylorhiza). b. Aster subsect. Heterochaeta (DC.) Benth. in Benth. & Hook., Gen. Pl. 2:272. 1873. Heterochaeta DC., Prodr. 5:282. 1836. Lectotype (designated here): Aster asteroides (DC.) O. Ktze. Aster sect. Alpigenit ser. Latibracteati Ling [nom. illeg.|, Fl. Reip. Pop. Sin. 224. 1985. [no Latin diagnosis]. Aster sect. Alpigeni subsect. Brachychaeti (Onno) Grierson {nom. illeg.|, Notes Roy. Bot. Gard. Edinb. 26:83. 1964 [basionym not cited by Grierson]. Aster [sect. Alpigeni| ser. Brachychaeti Onno, Bibl. Bot. 106:7. 1932. Lectotype (designated here): Aster tongolensis Franch. Aster sect. Alpigeni ser. Tongolenses Ling (nom. illeg.|, Fl. Retp. Pop. Sin. 213. 1985. [no Latin diagnosis]. Type: Aster tongolensis Franch. Aster sect. Alpigent ser. Asteroides Ling [nom. illeg.], Fl. Retp. Pop. Sin. 234. 1985. [no Latin diagnosis]. Type: Aster asteroides (DC.) O. Ktze. INCL: Aster asteroides(DC.) O. Ktze., A. brevis Hand.-Mazz., A. diploste- phioides (DC.) C.B. Clarke, A. falconert (C.B. Clarke) Hutch., A. farreri W.W. Smith, A. flaccidus Bunge, A. giraldit Diels, A. hololachnus Ling, A. jeffreyanus Diels, A. lattbracteatus Franch., A. likiangensis Franch., A. lipskyi Komar., A. megalanthus Ling, A. setchuenensis Franch., A. souliet Franch., A. tongolensis Franch., A. yunnanensis Franch. c. Aster subsect. Senectoides Ling (nom. nud. illeg.], Fl. Retp. Pop. Sin. 201. 1985. [no type or Latin diagnosis]. Aster sect. Alpigent ser. Senecioides Ling, [nom. illeg.|, Fl. Retp. Pop. Sin. 249. 1985. [no type or Latin diagnosis]. Aster sect. Alpigent ser. Batangenses Ling, [nom. illeg.|, Fl. Retp. Pop. Sin. 252. 1985. [no type or Latin diagnosis]. Nesom: Review of Aster taxonomy 247 INCL: Aster batangensis Bur. & Franch., A. rockianus Hand.-Mazz., A. seneciotdes Franch., A. statictfolius Franch. C. Aster sect. Ageratoides (Kitam.) Nesom, comb. et stat. nov. BA- SIONYM: Aster sect. Orthomeris ser. Ageratoides Kitamura, J. Jap. Bot. 12:535. 1936. Type: Aster ageratoides Turcz. Aster sect. Ageraton Tamamsch. (nom. illeg.), Fl. URSS 25:101. 1959. [no type or Latin diagnosis]. Aster (sect. Aster] ser. Turczaninowia (DC.) Kitam., J. Jap. Bot. 12:535. 1936. Turczaninowta DC., Prodr. 5:238. 1836. Type: Aster fastigiatus Fisch. (= Turczaninowra fasti- giata [Fisch.] DC.). INCL (e.g.): Aster alatipes Hemsl., A. ageratoides Turcz., A. baccharoides Steetz, A. falcifolius Hand.-Mazz., A. fastigiatus Fisch., A. formosanus Hay- ata, A. glehnit Fr. Schmidt, A. helenae Merr., A. homochlamydeus Hand.- Mazz., A. hunanensis Hand.-Mazz., A. lasiocladus Hayata, A. lururifolius Tamamsch., A. morrisonensis Hayata, A. nigromontanus Dunn, A. ovalt- folius Kitamura, A. philippinensis Moore, A. pycnophyllus W.W. Smith, A. sampsonii (Hance) Hemsl., A. stkkimensis Hook., A. taiwanensis Kitam., A. trinervius D. Don, A. turbinatus S. Moore, A. vestitus Franch. D. Aster sect. Calimeridei (DC.) Nesom, comb. nov. BASIONYM: Diplo- pappus sect. Calimeridet DC., Prodr. 5:276. 1836 (excluding all species but the type, see comments in discussion). Lectotype (designated here): Dtplopappus asper Less. [= Calendula hispida Thunb. = Aster bakeranus Burtt Davy ez C.A. Smith. Diplopappus Cass. sect. Herbaceae Harvey in Harvey & Sond., Fil. Cap. 3:84. 1865. Lectotype (designated here): Diplopappus asper Less. INCL: Seventeen species of southeast Africa (see Lippert 1973 and discus- sion above); the Asian Aster molliusculus (DC.) C.B. Clarke and A. brachytr- chus Franch. may also belong here (see comments in text). 248 PHYTOL @M¢GPa volume 77(3):141-297 September 1994 Aster Incertae Sedis 1. Aster sect. Bellidiastrum (Micheli ez Scopoli) Hayek, Fl. Stererm. 2:493. 1913. Belldiastrum Micheli ez Scopoli, Fl. Carn. 376. 1760 (not Cass. 1816; not Less. 1832). Type: Aster bellidiastrum (L.) Scop. (= Bellidiastrum michelit Cass. (Dict. Sci. Nat. 4, Suppl. 7. 1817.). Bellidtaster Dumort., Fl. Belg. 66. 1827. Margarita Gaud., Fl. Helv. 5:335. 1829. Brachyaster Ambrosi, Fl. Tirol. Austr. 2:379. 1857. INCL: Aster bellidiastrum (L.) Scop. 2. Aster [sect. Alpigenz| ser. Prainiani Ling, Fl. Reip. Pop. Sin. 360. 1985. Type: Aster praini (J.R. Drumm.) Y.L. Chen. Wardaster J. Small, Trans. Bot. Soc. Edinb. 29:230. 1926. Type: Wardaster lanuginosus J. Small. Chlamydites J.R. Drumm., Kew Bull. Misc. Inform. 90. 1907. Type: Chlamydites prainz J.R. Drumm. INCL: Aster lanuginosus (J. Small) Y.L. Chen, A. praini (J.R. Drumm.) Y.L. Chen. 3. Aster sect. Bipinnatisectt Grierson, Notes Royal Bot. Gard. Edinb. 26:83. 1964. Aster sect. Aster ser. Bipinnatisect: (Grierson) Ling, Fl. Rezp. Pop. Sin. 249. 1985. Type: Aster bipinnatisectus Ludlow in Grierson. INCL: Aster bipinnatisectus Ludlow in Grierson. 4. Aster (sect. Orthomeris] ser. Albescentes Ling, Fl. Retp. Pop. Sin. 357. 1985. Type: Aster albescens (DC.) Hand.-Mazz. INCL: Aster albescens (DC.) Hand.-Mazz., A. argyropholis Hand.-Mazz., A. fulgidulus Grierson, A. hypoleucus Hand.-Mazz., A. lavandulifolius Hand.- Mazz., A. polius Schneid. Nesom: Review of Aster taxonomy 249 5. The Aster tataricus group (see discussion in text). INCL: Aster faurert Levl. & Van., A. tataricus L.f. 6. The Asian species of “Brachyactis” (see discussion in text). INCL: Brachyactis chinensis Bur. & Franch., B. menthodora Benth., B. obovata Benth., B. pubescens (DC.) Aitch. & Clarke, B. royle:(DC.) Wendelbo. APPENDIX II. Taxonomy of American Asterinae (s. lat.) The genera are treated below in alphabetical sequence. Details of addi- tional synonyms, subcategories, and typification are found primarily in the following: Jones 1980a; Jones & Hiepko 1981; Jones & Lowry 1986; Lamboy & Jones 1987a; and Sundberg 1986. Asa Gray was equivocal in the designation of rank for infrageneric cat- egories; for consistency in the interpretation of such categories established by Asa Gray for Aster (1842, 1880, 1884) as well as for Solidago (see Ne- som 1993c), I have followed the interpretation and precedent set by Brizicky (1969), Holmgren (1979), and Jones (1980a). Following original indications by Gray, these later authors have regarded as SUBGENERA the substantive infrageneric names in larger print (and all capitals) and marked with the sym- bol “§” (e.g., ASTER, BIOTIA, IANTHE, ORITROPHIUM, ORTHOMERIS; Gray’s use of these taxa was consistent in all three publications, and in the latter two (1880, 1884) he clearly referred to them as subgenera of Aster. Ad- jectival subcategories of the subgenera in smaller print (upper and lower case in 1842, all upper in 1880) are treated as sections. A set of subsectional cat- egories for Aster was added by Gray in 1884, these in small print (upper and lower case) and italics. Species were listed by Jackson (in /nder Kewensis) for genera created by Rafinesque. Rafinesque, however, merely listed such species without making valid combinations for them, and Merrill (1949) has attributed the combina- tions to Jackson (as Rafin. ez B.D. Jackson in Index Kewensis 1895). I. ALMUTASTER A. Love & D. Love, Taxon 31:356. 1982. Type: Almutaster (Aster) pauciflorus (Nutt.) Love & Love. 250 PHYTOLOGIA volume 77(3):141-297 September 1994 Aster sp.-group Pauciflori Rydb., Fl. Rocky Mts. 789. 1917. Aster sect. Pauciflori (Rydb.) A.G. Jones [nom. superfi.|, Brittonia 32:233. 1980. (not Aster sect. Pauctflori Loudon 1830.). Type: Aster pauczflorus Nutt. 1. Almutaster pauciflorus (Nutt.) Love & Love, Taxon 31:356. 1982. BA- SIONYM: Aster pauciflorus Nutt., Gen. N. Amer. Pl. 2:154. 1818. I]. AMPELASTER Neson, gen. nov. Type: Ampelaster (Aster) carolinianus (Walt.) Nesom. Herbae perennes eglandulosae scandentes ad basim lignosae; caules dense hirsutulosi vel pilosi; folia oblanceolata vel oblongi- oblanceolata, ad basim auriculati-amplectentia; capitula solitaria vel 2-8 brevipedicellata in fasciculos laxis terminalibus; phyllaria crassa lineari-oblonga in longitudine subaequalia parum carinata, area apicali viridi ad basim truncata, plerumque reflexa ad apices; corollae disci anguste tubulosae; achenia glabra anguste cylindrica vel parum fusiformia, 2.5-3.0 mm longa, nervis 9-12 parum elevatis; pappus l-seriatus, setis ad apices attenuatis; chrornosomatum nu- merus n=9. Aster sect. Sagitttferi A. Gray, Synopt. Fl. 1(2):179. 1884. Virgulus sect. Sagittifert (A. Gray) Reveal & Keener, Taxon 30:650. 1981. Type: Aster carolnianus Walt. Aster sp.-group Caroliniana Small, Man. Southeast. Fl. 1367. 1933. Lasallea (sect. Grandiflorae] subsect. Carolinianae (Small) Semple & Brouillet, Amer. J. Bot. 67:1023. 1980. Type: Aster carolinianus Walt. 1. Ampelaster carolinianus (Walt.) Nesom, comb. nov. BASIONYM: Aster carolinianus Walt., Fl. Carol. 208. 1788. Lasallea caroliniana (Walt.) Semple & Brouillet, Amer. J. Bot. 67:1023. 1980. Virgulus carolinianus (Walt.) Reveal & Keener, Taxon 30:650. 1981. II]. CANADANTHUS Neson, gen. nov. Type: Canadanthus (Aster) modestus (Lindl.) Nesom. Nesom: Review of Aster taxonomy 251 Herbae perennes tenui-rhizomatosae, caulibus 3-8 dm elatis sim- plicibus ex basi singulatim exorientibus, vestimento (caulorum ac phyllariorum) glanduloso longi-stipitato; folia caulina eglandulosa epetiolata subamplectentia 5-12 cm longa lanceolata vel elliptici- lanceolata apice acuminato marginibus integris vel serratis; capit- ulescentia laxe corymboidea, capitulis in pedunculis foliaceis; phyl- laria lineari-lanceolata tenui-foliacea complanata in seriebus 2-3 in longitudine parum aequalibus, aream viridem apicalem caren- tia, haec seriei interioris saepe carinata plerumque purpurascentia; corollae disci anguste tubulosae; corollae radii 25-40 ligulis purpu- ratis circinatis; achenia eglandulosa oblanceolata vel anguste obo- vata 2.5-4.0 mm longa, 4-8 nervata, valde complanata, ad basim stipitata anguste acuta; pappus 1(-2)-seriatus, setis ad apices at- tenuatis; chromosomatum numerus n=9. 1. Canadanthus modestus (Lindl.) Nesom, comb. nov. BASIONYM: Aster modestus Lindl. in Hook., Fl. Bor.-Amer. 2:8. 1834. Weberaster modestus (Lindl.) Love & Love, Taxon 31:359. 1982. Aster unalaschkensis Less. var. major Hook., Fl. Bor.-Amer. 2:7. 1834. Aster major (Hook.) Porter, Mem. Torrey Bot. Club 5:325. 1894. Aster modestus Lindl. in Hook. var. major (Hook.) Muenscher, Fi. Whatcom Co., Wash. (Vasc. Pl.) 128. 1941. Aster sayianus Nutt., Trans. Amer. Philos. Soc., ser. 2, 7:294. 1840. IV. CHLORACANTHA Neson, Suh, Morgan, & Simpson, Phytologia 70:378. 1991. Type: Chloracantha spinosa (Benth.) Nesom. 1. Chloracantha spinosa (Benth.) Nesom, Phytologia 70:378. 1991. BA- SIONYM: Aster spinosus Benth., Pl. Hartweg. 20. 1839. a. Chloracantha spinosa (Benth.) Nesom var. jaliscensis (McVaugh) S.D. Sundb., Phytologia 70:388. 1991. BASIONYM: Aster spinosus Benth. var. jaliscensis McVaugh, Contr. Univ. Mich. Herb. 9:363. 1972. Erigeron ortegae S.F. Blake, Proc. Biol. Soc. Washington 37:55. 1924. b. Chloracantha spinosa (Benth.) Nesom var. spinosa 252 PHYTOLOGGIA volume 77(3):141-297 September 1994 c. Chloracantha spinosa (Benth.) Nesom var. spinostssima (Brandeg.) S.D. Sundb., Phytologia 70:386. 1991. BASIONYM: Aster spinosus Benth. var. spinosisstmus Brandeg., Univ. Calif. Publ. Bot. 6:375. 1917. d. Chloracantha spinosa(Benth.) Nesom var. strictospinosa S.D. Sundb., Phytologia 70:389. 1991. IV. DOELLINGERIA Nees, Gen. Sp. Aster. 177. 1832 [1833]. Type: Doellingeria umbellata (Mill.) Nees. A. Doellingeria sect. Doellingeria Aster subg. Doellingeria (Nees) A. Gray, Synopt. Fl. 1(2):196. 1884. Aster sect. Doellingeria (Nees) Kitam., J. Jap. Bot. 12:721. 1936. Diplopappus sect. Triplopappus Torr. & Gray, Fl. N. Amer. 2:182. 1841. Aster subg. Doellingeria sect. Triplopappus (Torr. & Gray) A.G. Jones, Brittonia 32:237. 1980. Type: Aster umbellatus Mill. Aster ser. Sohayakienses Kitamura, J. Jap. Bot. 12:722. 1936. Type: Aster sohayakiensis Koidzumi. a. Doellingeria ser. Doellingeria 1. Doellingeria infirma (Michx.) E. Greene, Pittonia 3:52. 1896. BA- SIONYM: Aster infirmus Michx., Fl. Bor.-Amer. 2:109. 1803. i) . Doellingeria sericocarpoides Small, Bull. Torrey Bot. Club 25:620. 1898. Aster sericocarpoides (Small) K. Schum., Just. Bot. Jahresb. 26(1):375. 1900. ~ Doellingerta umbellata (Miller) Nees, Gen. Sp. Aster. 178. 1832. BA- SIONYM: Aster umbellatus Miller, Gard. Dict., ed. 8, no. 22. 1768. a. Doellingeria umbellata (Miller) Nees var. umbellata b. Doellingeria umbellata (Miller) Nees var. pubens (A. Gray) Britton, Britton & Br. Illus. Fl. 3:392. 1898. BASIONYM: Aster umbella- tus Miller var. pubens A. Gray, Synopt. Fil. 1(2):197. 1884. — . Doellingeria sohayakiensis (Koidzumi) Nesom, Phytologia 75:456. 1993. BASIONYM: Aster sohayakiensis Koidzumi, Tokyo Bot. Mag. 37:56. 1923. Nesom: Review of Aster taxonomy 253 5. Doellingeria rugulosa (Maxim.) Nesom, Phytologia 75:456. 1993. BA- SIONYM: Aster rugulosus Maxim., Mel. Biol. 7:333. 1870. B. Doellingeria sect. Cordifolium (Kitamura) Nesom, Phytologia 75:456. 1993. BASIONYM: Kalimeris sect. Cordifolium Kitam., Mem. Coll. Sci. Kyoto Univ., ser. B. 8:312. 1937. Lectotype: Biotia japonica Miq. Aster sect. Teretiachaentum Kitamura, Mem. Coll. Sci. Kyoto Univ., ser. B. 8:357. 1937. Lectotype: Aster scaber Thunb. b. Doellingeria ser. Cordifolium (Kitamura) Nesom, Phytologia 75:456. 1993. BASIONYM: Kalimeris sect. Cordifolium Kitam., Mem. Coll. Sci. Kyoto Univ., ser. B. 8:312. 1937. Lectotype: Doellingeria japonica (Miq.) Nesom. 6. Doellingeria japonica (Miq.) Nesom, Phytologia 75:456. 1993. BA- SIONYM: Biotia japonica Miq., Ann. Mus. Bot. Lugduno-Batavum 2:170. 1866. Aster japonicus (Miq.) Franch. & Sav., Enum. Pl. Japon. 2:398. 1876. (not Aster japonicus Less. ex Nees 1832.). Aster miquelianus Hara [nom. nov.], J. Jap. Bot. 12:338. 1936. 7. Doellingeria marchandi (Levl.) Ling, Icon. Cormorph. Sin. 4:423. 1975. BASIONYM: Aster marchandii Levl., Fedde Repert. Sp. Nov. 11:306. 1912. 8. Doellingeria longipetiolata (Chang) Nesom, Phytologia 75:457. 1993. BA- SIONYM: Aster longipetiolatus Chang, Sunyatsenia 6:22. 1941. c. Doellingeria ser. Papposae Nesom, Phytologia 75:457. 1993. Type: Doellingerta scabra (Thunb.) Nees. 9. Doellingeria scabra (Thunb.) Nees, Gen. Sp. Aster. 183. 1832. BA- SIONYM: Aster scaber Thunb., Fl. Jap. 316. 1784. 10. Doellingeria komonoensis (Makino) Nesom, Phytologia 75:457. 1993. BASIONYM: Aster komonoensis Makino, Tokyo Bot. Mag. 12:65. 1898. 11. Doellingeria dimorphophylla (Franch. & Sav.) Nesom, Phytologia 75:457. 1993. BASIONYM: Aster dimorphophyllus Franch. & Sav., Enum. Pl. -Japon. 1:224. 1875. 254 PHYTOLOGGI4¢ volume 77(3):141-297 September 1994 Excluded taxa: - Doellingeria obovata (Nutt.) Nees = Oclemena reticulata (Pursh) Ne- som. Doellingeria reticulata (Pursh) E. Greene = Oclemena reticulata (Pursh) Nesom. V. EUCEPHALUS Nutt., Trans. Amer. Philos. Soc., ser. 2, 8:298. 1841. Aster {sect. Orthomeris| subsect.. Eucephalus (Nutt.) Benth. in Benth. & Hook., Gen. Pl. 2:273. 1873. Aster sect. Eucephalus (Nutt.) Munz & Keck ez A.G. Jones, Brittonia 32:236. 1980. Lectotype (Jones 1980a): Eucephalus elegans Nutt. 1. Eucephalus breweri (A. Gray) Nesom, comb. nov. BASIONYM: Chry sopsis brewert A. Gray, Proc. Amer. Acad. Arts 6:542. 1866. Heterotheca brewert (A. Gray) Shinners, Field & Lab. 29:71. 1951. Aster brewert (A. Gray) Semple, Syst. Bot. 13:545. 1988. Chrysopsis wrightit A. Gray, Synopt. Fl. 1(2):445. 1884. 2. Eucephalus brickellioides (E. Greene) Nesom, comb. nov. BASIONYM: Aster brickellioides E. Greene, Pittonia 2:16. 1889. 3. Eucephalus elegans Nutt., Trans. Amer. Phil. Soc. 2, ”':298. 1840. Aster el- egans (Nutt.) Torr. & Gray [comb. illeg.|, Fl. N. Amer. 2:159. 1841. (not Aster elegans Willd. 1803.). Aster perelegans Nelson & Macbr. {[nom. nov.|, Bot. Gaz. (Crawfordsville) 56:477. 1913. Eucephalus perelegans (Nelson & Macbr.) Weber, Phytologia 51:374. 1982. Eucephalus frigidus Gandoger, Bull. Soc. Bot. France 65:40. 1918. Eucephalus scaber Gandoger, Bull. Soc. Bot. France 65:40. 1918. 4. Eucephalus engelmannii (D.C. Eat.) E. Greene, Pittonia 3:54. 1896. BA- SIONYM: Aster elegans (Nutt.) Torr. & Gray var. engelmanni D.C. Eat., Bot. King Expl. 144. 1871. Aster engelmannu (D.C. Eat.) A. Gray, Synopt. Fl. 1(2):199. 1884. 5. Eucephalus glabratus (E. Greene) E. Greene, Pittonia 3:56. 1896. Aster glabratus (E. Greene) S.F. Blake ez Peck, Man. Higher Pl. Oregon 726. 1941. BASIONYM: Aster brickellioides E. Greene var. glabratus E. Greene, Pittonia 2:17. 1889. yar Nesom: Review of Aster taxonomy 255 Aster siskiyouensis Nelson & Macbr., Bot. Gaz. (Crawfordsville) 56:477. 1913. Eucephalus glandulosus Eastw., Proc. Calif. Acad. Sci., ser. 4, 20:157. 1931. 6. Eucephalus glaucescens (A. Gray) E. Greene, Pittonia 3:56. 1896. BA- SIONYM: Aster engelmannii (D.C. Eat.) A. Gray var. glaucescens A. Gray, Synopt. Fl. 1(2):200. 1884. Aster glaucescens (A. Gray) S.F. Blake, Rhodora 30:278. 1928. Eucephalus glaucophyllus Piper, Contr. U.S. Natl. Herb. 11:570. 1906. Aster glaucophyllus (Piper) Frye & Rigg, Northw. Fi. 385. 1912. Eucephalus serrulatus E. Greene, Pittonia 3:55. 1896. Aster serrulatus (E. Greene) Frye & Rigg, Northw. Fl. 385. 1912. ?Eucephalus macouni E. Greene, Pittonia 4:70. 1899. 7. Eucephalus gormani Piper, Proc. Biol. Soc. Washington 29:101. 1916. Aster gormanii (Piper) S.F. Blake, Rhodora 30:278. 1928. 8. Eucephalus ledophyllus (A. Gray) E. Greene, Pittonia 3:55. 1896. BA- SIONYM: Aster engelmannii (D.C. Eat.) A. Gray var. ledophyllus A. Gray, Proc. Amer. Acad. Arts 8:388. 1872. Aster ledophyllus (A. Gray) A. Gray, Proc. Amer. Acad. Arts 16:98. 1880. a. Eucephalus ledophyllus (A. Gray) E. Greene var. ledophyllus b. Eucephalus ledophyllus (A. Gray) E. Greene var. covillei (E. Greene) Nesom, comb. nov. BASIONYM: Eucephalus coville: E. Greene, Pittonia 3:162. 1897. Aster covillei (E. Greene) S.F. Blake ez Peck, Man. Higher Pl. Oregon 725. 1941. Aster ledophyllus (A. Gray) A. Gray var. covillei (E. Greene) Crong., Vasc. Pl. Pacif. Northw. 5:89. 1955. 9. Eucephalus paucicapitatus (B. Rob.) E. Greene, Pittonia 3:56. 1896. BA- SIONYM: Aster engelmannii (D.C. Eat.) A. Gray var. pauctcapitatus B. Rob., Proc. Amer. Acad. Arts 26:176. 1891. Aster paucicapttatus (B. Rob.) B. Rob., Proc. Amer. Acad. Arts 29:329. 1894. 10. Eucephalus tomentellus (E. Greene) E. Greene, Pittonia 3:55. 1896. BASIONYM: Sericocarpus tomentellus E. Greene, Pittonia 1:283. 1889. Aster tomentellus (E. Greene) Frye & Rigg, Northw. Fl. 385. 1912. (not Aster tomentellus Hook. & Arn. 1833.). Eucephalus bicolor Eastw., Proc. Calif. Acad. Sci., Ser. 4, 20:157. 1931. 256 PHYTOLOGIA volume 77(3):141-297 September 1994 11. Eucephalus vialis Bradshaw, Torreya 20:122. 1921. Aster vials (Brad- shaw) S.F. Blake, Rhodora 30:228. 1928. Sericocarpus stpet Henderson, Madrono 2:105. 1933. Excluded taxa: Eucephalus ericoides (L.) Nutt. = Symphyotrichum ericoides (L.) Ne- som. Eucephalus nemoralis (Aiton) E. Greene = Oclemena nemoralis (Aiton) E. Greene. Eucephalus wasatchensis (M.E- Jones) Rydb. = Zurybia wasatchensis (M.E. Jones) Nesom. Eucephalus glaucus Nutt. = Eurybia glauca (Nutt.) Nesom. Eucephalus formosus E. Greene = Eurybia glauca (Nutt.) Nesom. VI. EURYBIA (Cass.) S.F. Gray, Nat. Arrang. Brit. Pl. 2:464. 1821. BA- SIONYM: Aster subg. Eurybia Cass., Bull. Sci. Soc. Philom. Paris 1818:166. 1818. Lectotype (designated here, see discussion in text): Aster corymbosus Aiton (= Aster divaricatus L. = Eurybia divaricata [L.] Nesom). 1. Eurybia subg. Eurybia A. Eurybia sect. Eurybia Aster subg. Biottia DC. ex Torr. & Gray, Fl. N. Amer. 2:104. 1841. Aster sect. Biotia DC. ez Hoffmann in Engler & Prantl, Natirl. Pflanzenf. 4(5):162. 1890. Aster (subg. Aster sect. Aster] subsect. Biotia (DC. ez Torr. & Gray) Semple, Phytologia 58:429. 1984. Cited as Aster “sect. Biotia” by Jones 1980a, although she indicated in the same paper that this taxon (as published by Torrey & Gray) should be treated at the rank of subgenus (see comments at the beginning of Appendix II). Biotia DC. [nom. illeg.|, Prodr. 5:264. 1836. (not Biotia Cass. 1825; see Lamboy & Jones 1987b.). Lectotype (Jones 1980a): Aster schreberi Nees. INCL: Eurybia chlorolepis (Burgess) Nesom, EF. divaricata, E. furcata (Burgess) Nesom, E. jonesiae (Lamboy) Nesom, E. macrophylla (L.) Cass., E. mirabilis (Torr. & Gray) Nesom, E. schreberi (Nees) Nees. Nesom: Review of Aster taxonomy 257 B. Eurybia sect. Radulini (Rydb.) Nesom, comb. nov. BASIONYM: Aster sp.-group Radulini Rydb., Fl. Rocky Mts. 879. 1917. Aster sect. Radulini (Rydb.) A.G. Jones, Brittonia 32:237. 1980. Type: Aster radulinus A. Gray. a. Eurybia subsect. Radulini (Rydb.) Nesom, comb. nov. BASIONYM: Aster sp.-group Radulini Rydb., Fl. Rocky Mts. 879. 1917. Type: Aster radulinus A. Gray. Weberaster Love & Love, Taxon 31:359. 1982. Type: Weberaster (Aster) radulinus (A. Gray) Love & Love. INCL: Eurybia conspicua (Lindl.) Nesom, E. radula (Aiton) Nesom, E. radulina (A. Gray) Nesom, E. sazicastellit (Campbell & Medley) Nesom. b. Eurybia subsect. Sibiricae Nesom, subsect. nov. Type: Eurybia sibirica (L.) Nesom. Phyllariis herbaceis, capitulis in numero deminutis distinctae. INCL: Eurybia merita (A. Nelson) Nesom, E. pygmaea (Lindl.) Nesom, E. stbirica. C. Eurybia sect. Integrifoliae Nesom, sect. nov. Type: Eurybia integrifolia (Nutt.) Nesom. Foliis basalibus persistentibus oblanceolatis integribusque, ca- pitulis in capitulescentia spicata plerumque dispositis distinctae. INCL: Eurybia integrifolia. D. Eurybia sect. Calliastrum (Torr. & Gray) Nesom, comb. nov. BA- SIONYM: Aster subg. Calliastrum Torr. & Gray, Fl. N. Amer. 2:106. 1841. Aster sect. Calliastrum (Torr. & Gray) Benth. in Benth. & Hook., Gen. Pl. 2:271. 1873. Lectotype designated here: Aster spectabilts Aiton. Aster sect. Spectabiles A. Gray, Synopt. Fl. 1(2):175. 1884. Type: Aster spectabils Aiton. 258 PHYTOLOGIA volume 77(3):141-297 September 1994 The group described by Gray in 1884 as sect. Spectabzles was essentially the same as he described as subg. Calliastrum in 1841, as noted by Gray himself. From sect. Spectabiles, he transferred Aster paludosus to subg. Heleastrum; to it, he added A. radulinus and A. herveyi A. Gray. To reflect the essential identity of these two groups, I have lectotypified sect. Calkastrum with the same species that stands as the type of sect. Spectabiles. INCL: Eurybia compacta Nesom, E. spectabilis (Aiton) Nesom, E. surcu- losa (Michx.) Nesom. E. Eurybia sect. Herrickia (Torr. & Gray) Nesom, comb. et stat. nov. BA- SIONYM: Herrickia Wooton & Standl., Contr. U.S. Natl. Herb. 16:186. 1913. Type: Herrickia horrida Wooton & Standl. (= Eurybia horrida [Wooton & Standl.] Nesom). INCL: Eurybia glauca (Nutt.) Nesom, EF. horrida, E. pulchra (S.F. Blake) Nesom, E. wasatchensis (M.E. Jones) Nesom. 2. Eurybia subg. Heleastrum (DC.) Nesom, comb. nov. BASIONYM: Heleastrum DC., Prodr. 5:263. 1836. Aster subg. Heleastrum (DC.) A. Gray, Proc. Amer. Acad. Arts 16:97. 1880. [Synopt. Fl. 1(2):173. 1884.]. Aster [sect. Calliastrum] subsect. Heleastrum (DC.) Benth in Benth. & Hook., Gen. Pl. 2:271. 1873. Lectotype (Jones 1980a): Aster paludosus Aiton. F. Eurybia sect. Heleastrum (DC.) Nesom, comb. et stat. nov. BASIONYM: Heleastrum DC., Prodr. 5:263. 1836. Lectotype (Jones 1980a): Aster paludosus Aiton. Leiachenis Rafin., Fl. Tellur. 2:45. 1836 [1837]. Lectotype (designated here): Aster paludosus Aiton. INCL: Eurybia avita (Alexander) Nesom, EF. hemispherica (Alexander) Nesom, E. paludosa (Aiton) Nesom. G. Eurybia sect. Eryngiifolii (Alexander) Nesom, comb. nov. BASIONYM: Aster sp.-group Eryngitfolii Alexander in Small, Man. Southeast. FI. 1365. 1933. Aster [sect. Heleastrum| subsect. Eryngtifolii (Alexander) Semple, Phytologia 58:429. 1985. Type: Aster eryngtfolius Torr. & Gray. Nesom: Review of Aster taxonomy 259 INCL: Eurybia eryngiifolia (Torr. & Gray) Nesom, E. spinulosa (Chapm.) Nesom. H. Eurybia subg. Heleastrum sect. Chapmaniani (Semple) Nesom, comb. nov. BASIONYM: Aster [sect. Heleastrum] subsect. Chapmanzani Sem- ple, Phytologia 58:429. 1985. Type: Aster chapmanii Torr. & Gray. INCL: Eurybia chapmanii (Torr. & Gray) Nesom. Species of Eurybia: 1. Eurybia avita (Alexander) Nesom, comb. nov. BASIONYM: Aster avitus Alexander, Castanea 4:60: 1939. 2. Eurybia chapmanii (Torr. & Gray) Nesom, nom. nov. BASIONYM: Aster chapmanii Torr. & Gray, Fl. N. Amer. 2:161. 1841. Heleastrum chapmanii (Torr. & Gray) Shinners (nom. illeg.], Sida 3:348. 1969 (not Heleastrum chapmanii (Torr. & Gray] E. Greene 1896.). 3. Eurybia chlorolepis (Burgess) Nesom, comb. nov. BASIONYM: Aster chlorolepis Burgess in Small, Fl. Southeast. U.S. 1211, 1339. 1903. 4. Eurybia compacta Nesom, nom. nov. Based on: Aster gracilis Nutt., Gen. N. Amer. Pl. 2:158. 1818 (not Eurybia gracilis Benth. 1837.). 5. Eurybia conspicua (Lindl.) Nesom, comb. nov. BASIONYM: Aster conspicuus Lindl. in Hook., Fl. Bor. Amer. 2:7. 1834. 6. Eurybia divaricata (L.) Nesom, comb. nov. BASIONYM: Aster divari- catus L., Sp. Pl. 873. 1753. Aster corymbosus Sol. ez Aiton, Hort. Kew. 3:207. 1789. Eurybia corymbosa (Aiton) Cass., Dict. Sci. Nat. 37:487. 1825. 7. Eurybia eryngiifolia (Torr. & Gray) Nesom, comb. nov. BASIONYM: Aster eryngitfolius Torr. & Gray, Fl. N. Amer. 2:502. 1843. Prionopsis chapmanii Torr. & Gray, Fl. N. Amer. 2:245. 1842. Heleas- trum chapmani (Torr. & Gray) E. Greene, Pittonia 3:49. 1896. 8. Eurybia furcata (Burgess) Nesom, comb. nov. BASIONYM: Aster furcatus Burgess in Britton & Brown, JIlus. Fl. 3:358. 1898. 260 PHYTOLOGIA volume 77(3):141-297 September 1994 9. Eurybia glauca (Nutt.) Nesom, comb. nov. BASIONYM: Eucephalus glaucus Nutt., Trans. Amer. Philos. Soc., ser. 2, 7:299. 1841. Aster glaucus (Nutt.) Torr. & Gray [nom. illeg.|, Fl. N. Amer. 2:159. 1841. (not Nees 1818.). Aster glaucodes S.F. Blake [nom. nov.], Proc. Biol. Soc. Washington 35:174. 1922. Eucephalus formosus E. Greene, Pittonia 4:156. 1900. Aster glaucodes S.F. Blake var. formosus (E. Greene) Kittell in Tidestrom & Kittell, Fl. Ariz. & New Mezico 404. 1941. 10. Eurybia hemispherica (Alexander) Nesom, comb. nov. BASIONYM: Aster hemisphericus Alexander~in Small, Man. Southeast. Fl. 1391, 1509. 1933. Heleastrum hemisphericum (Alexander) Shinners, Field & Lab. 17:170. 1949. Aster paludosus Sol. er Aiton subsp. hemtsphericus (Alexander) Cronq., Bull. Torrey Bot. Club 74:145. 1947. Aster palu- dosus Sol. ez Aiton var. hemisphericus (Alexander) Waterf., Rhodora 62:320. 1960. Aster pedionomus Alexander in Small, Man. Southeast. Fil. 1391, 1509. 1933. Aster gattingeri Alexander in Small, Man. Southeast. Fl. 1391, 1509. 1933. Aster verutifolius Alexander in Small, Man. Southeast. Fl. 1392, 1509. 1933. 11. Eurybia horrida (Wooton & Standl.) Nesom, comb. nov. BASIONYM: Herrickia horrida Wooton & Standl., Contr. U.S. Natl. Herb. 16:186. 1913. Aster horridus (Wooton & Standl.) S.F. Blake, J. Washington Acad. Sci. 27:379. 1937. 12. Eurybia integrifolia (Nutt.) Nesom, comb. nov. BASIONYM: Aster integrifokus Nutt., Proc. Amer. Philos. Soc., ser. 2, 7:291. 1840. 13. Eurybia jonesiae (Lamboy) Nesom, comb. nov. BASIONYM: Aster jonesiae Lamboy, Syst. Bot. 13:192. 1988. 14. Eurybia macrophylla (L.) Cass., Dict. Sct. Nat. 37:487. 1825. BA- SIONYM: Aster macrophyllus L., Sp. Pl., (ed. 2) 2:1232. 1763. Eurybia jussiei Cass., Dict. Sci. Nat. 37:487. 1825. (see Lamboy & Jones 1987a.). 15. Eurybia merita (A. Nelson) Nesom, comb. nov. BASIONYM: Aster meritus A. Nelson, Bot. Gaz. (Crawfordsville) 37:268. 1904. Aster richardsoniu Spreng. var. meritus (A. Nelson) Raup, Contr. Arnold Arb. Nesom: Review of Aster taxonomy 261 16. Ad» 18. 19. 20. 21. 22. 23. 24. 6:204. 1934. Aster stbiricus L. var. meritus (A. Nelson) Raup, Sargentia 6:240. 1947. Eurybia mirabilis (Torr. & Gray) Nesom, comb. nov. BASIONYM: Aster mirabilis Torr. & Gray, Fl. N. Amer. 2:165. 1841. Eurybia paludosa (Aiton) Nesom, comb. nov. BASIONYM: Aster paludosus Sol. ez Aiton, Hort. Kew. 3:201. 1789. Heleastrum paludosum (Aiton) DC., Prodr. 5:264. 1836. Eurybia pulchra (S.F. Blake) Nesom, comb. et stai. nov. BASIONYM: Aster glaucodes §.F. Blake subsp. pulcher S.F. Blake, Proc. Biol. Soc. Washington 35:174. 1922. Eurybia pygmaea (Lindl.) Nesom, comb. nov. BASIONYM: Aster pygmaeus Lindl. in Hook., Fl. Bor.-Amer. 2:6. 1834. Aster sibtricus L. var. pygmaeus (Lindl.) Cody, Canad. Field-Nat. 68:117. 1954. Aster sibiricus L. subsp. pygmaeus (Lindl.) Love & Love, Bot. Notiser 128:521. 1975. Eurybia radula (Aiton) Nesom, comb. nov. BASIONYM: Aster radula Sol. ex Aiton, Hort. Kew. 3:210. 1789. Eurybia radulina (A. Gray) Nesom, comb. nov. BASIONYM: Aster radulinus A. Gray, Proc. Amer. Acad. Arts 8:388. 1872. Weberaster radulinus (A. Gray) Love & Love, Taxon 31:359. 1982. Eurybia saxicastellii (Campbell & Medley) Nesom, comb. nov. BA- SIONYM: Aster sazicastellii Campbell & Medley, Sida 13:277. 1989. Eurybia schreberi (Nees) Nees, Gen. Sp. Aster. 137. 1832. BASIONYM: Aster schrebert Nees, Synops. Ast. Herb. 16. 1818. Aster glomeratus Bernh. in Nees [pro syn.|, Gen. Sp. Aster. 139. 1832. Eurybia glomerata (Bernh.) Nees, Gen. Sp. Aster. 139. 1832. Eurybia sibirica (L.) Nesom, comb. nov. BASIONYM: Aster stbiricus L., Sp. Pl. (ed. 2) 872. 1753. a. Eurybia sibirica (L.) Nesom var. stbirica b. Eurybia sibirica (L.) Nesom var. gigantea (Spreng.) Nesom, comb. nov. BASIONYM: Aster richardsonit Spreng. var. giganteus Hook., Fl. Bor.-Amer. 2:7. 1834. Aster sibirtcus L. var. giganteus (Hook.) A. Gray, Synopt. Fl. 1(2):177. 1884. 262 PHYTOLOGIA volume 77(3):141-297 September 1994 Aster richardsonu Spreng., Syst. Veg. 3:258. 1826. Aster stbirt- cus L. subsp. richardsonii (Spreng.) Love & Love, Bot. Notiser 128:521. 1975. Aster behringensis Gandoger, Bull. Soc. Bot. France 65:38. 1918. c. Eurybia sibirica (L.) Nesom var. subintegerrima (Trautv.) Ne- som, comb. nov. BASIONYM: Aster subintegerrimus Trautv. in Middendorf, Retse 1:161. 1847. Aster sibiricus L. subsp. subinte- gerrimus (Trautv.) Love & Love, Bot. Notiser 128:521. 1975. 25. Eurybia spectabilis (Aiton) Nesom, comb. nov. BASIONYM: Aster spectabilis Sol. ex Aiton, Hort. Kew. 3:209. 1789. Eurybia commizta Nees, Gen. Sp. Aster. 142. 1832 [1833]. Aster commiztus (Nees) O. Kuntze, Rev. Gen. Pl. 2:315. 1891. 26. Eurybia spinulosa (Chapm.) Nesom, comb. nov. BASIONYM: Aster spinulosus Chapm., Fil. Southern U.S. 199. 1860. Heleastrum spinulosum (Chapm.) E. Greene, Pittonia 3:50. 1896. 27. Eurybia surculosa (Michx.) Nesom, comb. nov. BASIONYM: Aster surculosus Michx., Fl. Bor.-Amer. 2:112. 1803. 28. Eurybia wasatchensis (M.E. Jones) Nesom, comb. nov. BASIONYM: Aster glaucus (Nutt.) Torr. & Gray var. wasatchensis M.E. Jones, Proc. Calif. Acad. Sci., ser. 2, 5:694. 1895. Eucephalus wasatchensis (M.E. Jones) Rydb., Fl. Rocky Mts. 878, 1067. 1917. Aster wasatchensis (M.E. Jones) S.F. Blake, Contr. U.S. Natl. Herb. 25:557. 1925. Hybrid: Eurybia x herveyi (A. Gray) Nesom, comb. nov. BASIONYM: Aster herveyt A. Gray [pro sp.|, Manual, (ed. 5) 229. 1867. [E. macro- _ phylla x E. spectabilis; Uttal 1962.]. Excluded taxa: Biotta spp. from Asia (= Asters. str. and Doellingeria). Heleastrum album (Nutt.) DC. = Oligoneuron album (Nutt.) Nesom. VII. JONACTIS E. Greene, Pittonia 3:245. 1897. Type: lonactis hnariifolia (L.) E. Greene. Nesom: Review of Aster taxonomy 263 Diplopappus Cass. subg. Janthe Torr. & Gray, Fl. N. Amer. 2:181. 1841. Aster subg. Janthe (Torr. & Gray) A. Gray, Synopt. Fl. 1(2):197. 1884. Type: Jonactts linaritfola (L.) E. Greene. 1. Jonactis alpina (Nutt.) E. Greene, Pittonia 3:245. 1897. BASIONYM: Chrysopsis alpina Nutt., J. Acad. Philad. 7:34. 1834. Aster scopulorum A. Gray [nom. nov.], Proc. Amer. Acad. Arts 16:98. 1880. (not Aster alpinus L. 1753.). 2. Ionactis elegans (Soreng & Spellenb.) Nesom, Phytologia 73:420. 1992. BASIONYM: Chaetopappa elegans Soreng & Spellenb., Syst. Bot. 9:1. 1984. 3. Ionactis caelestis Leary & Nesom, Brittonia 44:247. 1992. 4. Ionactis iinarifolia (L.) E. Greene, Pittonia 3:245. 1897. BASIONYM: Aster linaritfolius L., Sp. Pl., (ed. 2) 874. 1753. Aster lhinarifolius L. var. victorint:s Fernald, Rhodora 16:194. 1914. 5. Ionactis stenomeres (A. Gray) E. Greene, Pittonia 3:246. 1897. BA- SIONYM: Aster stenomeres A. Gray, Proc. Amer. Acad. Arts 17:209. 1882. VIII. OCLEMENA E. Greene, Leafl. Bot. Observ. Crit. i:4. 1903. Type: Aster acuminatus Michx. Aster subg. Orthomeris Torr. & Gray, Fl. N. Amer. 2:156. 1841. (pro parte). Aster sect. Orthomeris (Torr. & Gray) Benth. in Benth. & Hook., Gen. Pl. 2:273. 1873. Aster ser. Orthomeris (Torr. & Gray) Kitam., J. Jap. Bot. 12:533. 1936. Lectotype (designated here): Aster acuminatus Michx. (see explanatory comments in text). Galatella sect. Calianthus Nutt., Trans. Amer. Philos. Soc., ser. 2, 7:303. 1840. Type: Aster nemoralis Aiton. Aster [subg. Orthomeris] sect. Nemorali House, New York State Mus. Bull. 254:710. 1924. Type: Aster nemoralis Aiton. 264 PHY TOLO GIA volume 77(3):141-297 September 1994 Aster [subg. Doellingeria] sect. Acuminati (Alexander) A.G. Jones, Brit- - tonia 32:237. 1980. Aster sp.-group Acumznat: Alexander in Small, Man. Southeast. Fl. 1365. 1933. Type: Aster acuminatus Michx. 1. Oclemena acuminata (Michx.) E. Greene, Leafl. Bot. Observ. Crit. 1:4. 1903. BASIONYM: Aster acuminatus Michx., Fl. Bor.-Amer. 2:109. 1803. Aster acuminatus Michx. var. magdalenensis Fernald, Rhodora 51:101. 1949. 2. Oclemena nemoralis (Aiton) E. Greene, Leafl. Bot. Observ. Crit. 1:5. 1903. BASIONYM: Aster nemoralis Sol. ex Aiton, Hort. Kew. 3:198. 1789. Galatella nemoralis (Aiton) Nees, Gen. Sp. Ast. 173. 1832. Eu- cephalus nemoralis (Aiton) E. Greene, Pittonia 3:57. 1896. Aster nemoralis Sol. ex Aiton forma albiflora Fernald, Rhodora 51:99. 1949. 3. Oclemena reticulata (Pursh) Nesom, comb. nov. BASIONYM: Aster reticulatus Pursh, Fl. Amer. Sept. 2:458. 1814. Doellingeria reticulata (Pursh) E. Greene, Pittonia 3:50. 1896. Inula obovata Nutt., Gen. N. Amer. 2:152. 1818. Doellingeria obovata (Nutt.) Nees, Gen. Sp. Aster. 182. 1832. Diplopappus obovatus (Nutt.) Torr. & Gray, Fl. N. Amer. 2:184. 1841. Aster dichotomus Ell., Sketch 2:366. 1824. Hybrid: Oclemena x blakei (Porter) Nesom, comb. nov. BASIONYM: Aster nemoralis Sol. ex Aiton var. blaket Porter, Bull. Torrey Bot. Club 21:311. 1894. Aster blakez (Porter) House [pro sp.|, N.Y. State Mu- seum Bull. 219-220:244. 1920. [Oclemena nemoralis x O. acumt- natal. Aster nemoralis Sol. er Aiton var. major Peck, N.Y. State Museum Rep. 47:115. 1894. IX. OREOSTEMMA E. Greene [nom. nov.], Pittonia 4:224. 1900. Based on Oreastrum E. Greene, Pittonia 3:146. 1896 (not Oriastrum Poep- pig 1843). Aster subg. Oreostemma (E. Greene) Peck, Man. Higher Pl. Oregon 719. 1941. Nesom: Review of Aster taxonomy 265 Type: Oreostemma alpigenum (Torr. & Gray) E. Greene. 1. Oreostemma alpigenum (Torr. & Gray) E. Greene, Pittonia 4:224. 1900. BASIONYM: Haplopappus alpigenus Torr. & Gray, Fl. N. Amer. 2:241. 1842. Aster alpigenus (Torr. & Gray) A. Gray, Proc. Amer. Acad. Arts 8:389. 1872. Oreastrum alpigenum (Torr. & Gray) E. Greene, Pittonia 3:147. 1896. a. Oreostemma alpigenum (Torr. & Gray) E. Greene var. alprgenum b. Oreostemma alpigenum (Torr. & Gray) E. Greene var. andersoniu (A. Gray) Nesom, Phytologia 74:312. 1993. BASIONYM: Erigeron andersoni A. Gray, Proc. Amer. Acad. Arts 6:540. 1865. Aster andersonit (A. Gray) A. Gray, Proc. Amer. Acad. Arts 7:352. 1868. Oreastrum andersonit (A. Gray) E. Greene, Pittonia 3:147. 1896. Oreostemma andersonit (A. Gray) E. Greene, Pittonia 4:224. 1900. Aster alpigenus (Torr. & Gray) A. Gray subsp. anderson (A. Gray) Onno, Bibl. Bot. 26 (Heft 106):15. 1932. Aster alpigenus (Torr. & Gray) A. Gray var. andersonii (A. Gray) Peck, Man. Higher Pl. Oregon 721. 1941. c. Oreostemma alpigenum (Torr. & Gray) E. Greene var. haydenz (T.C. Porter) Nesom, Phytologia 74:313. 1993. BASIONYM: Aster hay- dentt T.C. Porter, Cat. Pl. 485 in Hayden, Prelim. Rep. U.S. Geol. Surv. Montana. 1872. Oreastrum haydenii (T.C. Porter) Rydb., Mem. New York Bot. Gard. 1:398. 1900. Oreostemma haydeni (T.C. Porter) E. Greene, Pittonia 4:224. 1900. Aster alpigenus (Torr. & Gray) A. Gray subsp. haydenit (T.C. Porter) Cronq., Leafl. West Bot. 5:77. 1948. Aster alpigenus (Torr. & Gray) A. Gray var. hayden (T.C. Porter) Cronq., Vasc. Pl. Pactfic Northw. 5:76. 1955. 2. Oreostemma elatum (E. Greene) E. Greene, Pittonia 4:224. 1900. BA- SIONYM: Oreastrum elatum E. Greene, Pittonia 3:147. 1896. Aster elatus (E. Greene) Cronq., Leafl. West. Bot. 5:80. 1948. 3. Oreostemma peirsonii (C.W. Sharsmith) Nesom, Phytologia 74:314. 1993. BASIONYM: Aster peirsoni C.W. Sharsmith, Leafl. West. Bot. 5:50. 1947. X. PSILACTIS A. Gray, Mem. Amer. Acad. Arts, ser. 2, 4:71. 1849. Machaer- anthera sect. Psilactis (A. Gray) Turner & Horne, Brittonia 16:321. 1964. Type: Psilactis asteroides A. Gray. 266 PHYTOLOGIA volume 77(3):141-297 September 1994 1. Pstlactis asteroides A. Gray, Mem. Amer. Acad. Arts, ser. 2, 4:72. 1849. (not Aster asteroides [DC.| Kuntze 1891.; not Aster asteroides [Colla] Rusby 1893.). Aster boltoniae E. Greene, Pittonia 3:248. 1897. Machaer- anthera boltoniae (E. Greene) Turner & Horne, Brittonia 16:330. 1964. (not Machaeranthera asteroides {Torr.| E. Greene 1892.). 2. Psilactis brevilingulata Sch.-Bip. er Hemsley, Diagn. Pl. Nov. Mezic. 2:34. 1879. Machaeranthera brevilingulata (Sch.-Bip. er Hemsley) Turner & Horne, Brittonia 16:324. 1964. Aster brevilingulatus (Sch.-Bip. er Hem- sley) McVaugh, Contr. Univ. Michigan Herb. 9:362. 1972. 3. Psilactis gentry: (Standley) Morgan, Syst. Bot. 18:302. 1993. BA- SIONYM: Aster gentry: Standley, Field Mus. Natl. Hist., Bot. Ser. 22:60. 1940. Machaeranthera gentry: (Standley) R.C. Jackson ez B.L. Turner, Phytologia 25:57. 1972. Machaeranthera mezicana Turner & Horne, Brittonia 16:329. 1964. 4. Psilactis heterocarpa (Hartman & Lane) Morgan, Syst. Bot. 18:301. 1993. BASIONYM: Machaeranthera heterocarpa Hartman & Lane, Brittonia 39:253. 1987. 5. Psilactis odysseus (Nesom) Morgan, Syst. Bot. 18:298. 1993. BA- SIONYM: Machaeranthera odysseus Nesom, Syst. Bot. 218. 1978. 6. Pstlactis tenuis S. Wats., Proc. Amer. Acad. Arts 26:139. 1891. Machaer- anthera tenuis (S. Wats.) Turner & Horne, Brittonia 16:330. 1964. XI. SERICOCARPUS Nees, Gen. Sp. Aster. 148. 1832 [1833]. Aster subg. Sericocarpus (Nees) A.G. Jones, Brittonia 32:238. 1980. Aster sect. Sericocarpus (Nees) Semple, Phytologia 58:429. 1985. Type: Sericocarpus solidagineus (Michx.) Nees = Serico- carpus linifolius (L.) B.S.P. 1. Sericocarpus asteroides (L.) B.S.P., Prelim. Cat. N.Y. Pl. 26. 1888. BA- SIONYM: Conyza asteroides L., Sp. Pl. 2:861. 1753. Aster paternus Cronq. {nom. nov.|, Bull. Torrey Bot. Club 74:149. 1947. Aster aster- oides MacMillan [nom. nov. illeg.| 1892. (not Aster asteroides {DC.| Kuntze 1891.; not Aster asteroides [Colla] Rusby 1893.). Cronquist’s new name (Aster paternus) is the correct one if this species is treated within Aster, in contrast to an earlier suggestion of mine (Nesom 1993b.). Nesom: Review of Aster taxonomy 267 2. Sericocarpus linifolius (L.) B.S.P., Prelim. Cat. N.Y. Pl. 26. 1888. BA- SIONYM: Conyza linifolia L., Sp. Pl. 2:861. 1753. Aster solidagineus Michx. [nom. nov.], Fl. Bor.-Amer. 2:108. 1803. (not Aster hnifolius L. 1753.). Sericocarpus solidagineus (Michx.) Nees, Gen. Sp. Aster. 149. 1832. 3. Sericocarpus oregonensts Nutt., Trans. Amer. Philos. Soc., ser. 2, 7:302. 1841. Aster oregonensis (Nutt.) Cronq., Vasc. Pl. Pacif. Northw. 5:80. 1955. a. Sericocarpus oregonensis Nutt. var. oregonensis b. Sericocarpus oregonensis Nutt. var. californicus (Durand) Nesom, Phytologia 75:51. 1993. BASIONYM: Sericocarpus californicus Durand, J. Acad. Nat. Sci. Philad., ser. 2, 3:90. 1855. Sertcocarpus oregonensis Nutt. var. californicus (Durand) Ferris, Contr. Dudley Herb. 5:100. 1958. 4. Sericocarpus rigidus Lindl. in Hook., Fl. Bor.-Amer. 2:14. 1834. Aster curtus Crongq. [nom. nov.], Vasc. Pl. Pacif. Northw. 5:80. 1955. (not Aster rigidus L. 1753.). 5. Sericocarpus tortifolius (Michx.) Nees, Gen. Sp. Aster. 151. 1832. BA- SIONYM: Aster tortifolius Michx., Fl. Bor.-Amer. 2:109. 1803. Excluded taxa: Sericocarpus sipei Henderson = Eucephalus vialis Bradshaw. Sericocarpus tomentellus E. Greene = Eucephalus tomentellus (E. Greene) E. Greene. Sericocarpus woodhousei Buckley = Isocoma pluriflora (Torr. & Gray) E. Greene. © XII. SYMPHYOTRICHUM Nees, Gen. Sp. Aster. 135. 1832 [1833]. Aster subg. Symphyotrichum (Nees) A.G. Jones, Brittonia 32:234. 1980. Type: Symphyotrichum unctuosum Nees (= Aster novti- belgz: L.). 1. Symphyotrichum subg. Symphyotrichum A. Symphyotrichum sect. Symphyotrichum 268 PHY TOLO@IA volume 77(3):141-297 September 1994 Aster sect. Salictfolii Torr. & Gray, Fl. N. Amer. 2:134. 1841. Type: Aster salicifolius Lam. (= Aster puniceus L.). Aster |sect. Homophylli] subsect. Vulgares A. Gray, Synopt. Fl. 1(2):187. 1884. Lectotype (designated here): Aster novi-belgiz L. INCL: Symphyotrichum anticostense (Fernald) Nesom, S. crentfolium (Fer- nald) Nesom, S. elliotts (Torr. & Gray) Nesom, S. firmum (Nees) Nesom, S. longifolum (Lam.) Nesom, S. novi-belgit (L.) Nesom, S. prenanthoides (Muhl. ex Willd.) Nesom, S. puniceum (L.) Love & Love, S. subgeminatum (Fernald) Nesom. B. Symphyotrichum sect. Cordifolii (G. Don) Nesom, comb. nov. BA- SIONYM: Aster sect. Cordtfolii G. Don in Loudon, Hort. Brit. 347. 1830. Type: Aster cordifolius L. (= Aster heterophyllus Willd.). Aster [sect. Genuinit Nees] B Heterophylli Nees, Gen. Sp. Aster. 52. 1832. Aster sect. Heterophylli (Nees) A. Gray, Synopt. Fl. 1(2):181. 1884. Aster (subg. Aster sect. Dumosi| subsect. Heterophylli (Nees) Semple, Phytologia 58:429. 1985. Type: Aster cordifolius L. (= Aster heterophyllus Willd.). INCL: Symphyotrichum anomalum (Engelm.) Nesom, S. ciliolatum (Lindl.) Love & Love, S. cordifolium (L.) Nesom, S. drummondii (Lindl.) Nesom, S. lowrieanum (Porter) Nesom, S. sagittifolium (Wedem. er Willd.) Nesom, S. shortu (Lindl.) Nesom, S. undulatum (L.) Nesom, S. urophyllum (DC.) Ne- som. C. Symphyotrichum sect. Concinni (Nees) Nesom, comb. nov. BASIO- NYM: Aster [sect. Genuint B Homophylli] sp.-group Concinni Nees, Gen. Sp. Aster. 118. 1832. Aster sect. Concinni (Nees) Torr. & Gray, Fl. N. Amer. 2:115. 1841. Type: Aster concinnus Willd. (= Aster laevis L.). a. Symphyotrichum subsect. Laeves (A. Gray) Nesom, comb. nov. BA- SIONYM: Aster {sect. Homophylli| subsect. Laeves A. Gray, Synopt. FI. 1(2):183. 1884. Type: Aster laevis L. Nesom: Review of Aster taxonomy 269 Aster [sect. Genuini B Homophylli] sp.-group Concinni Nees, Gen. Sp. Aster. 118. 1832. Type: Aster concinnus Willd. (= Aster laevis L.). INCL: Symphyotrichum laeve (L.) Love & Love, S. oolentangiense (Rid- dell) Nesom, S. retroflecum (DC.) Nesom. b. Symphyotrichum subsect. Turbinelli (Rydb.) Nesom, comb. nov. BA- SIONYM: Aster sp.-group Turbinelli Rydb., Fl. Prairies & Plains 803. 1932. Aster (sect. Eucephalus| subsect. Turbinel (Rydb.) A.G. Jones, Brittonia 32:237. 1980. Aster subg. Symphyotrichum sect. Turbinelh (Rydb.) A.G. Jones, Illinois Nat. Hist. Survey Bull. 34:144. 1989. Type: Aster turbinellus Lindl. INCL: Symphyotrichum turbinellum (Lindl.) Nesom. D. Symphyotrichum sect. Dumosi (Torr. & Gray) Nesom, comd. nov. BA- SIONYM: Aster sect. Dumosi Torr. & Gray, Fl. N. Amer. 2:127. 1841. Type: Aster dumosus L. a. Symphyotrichum subsect. Dumosi (Torr. & Gray) Nesom, comb. nov. BASIONYM: Aster sect. Dumosi Torr. & Gray, Fl. N. Amer. 2:127. 1841. Type: Aster dumosus L. INCL: Symphyotrichum dumosum (L.) Nesom, S. simmondsii (Small) Ne- som. b. Symphyotrichum subsect. Divergentes (A. Gray) Nesom, comb. nov. BASIONYM: Aster [sect. Homophylli] subsect. [vergentes A. Gray, Synopt. Fl. 1(2):185. 1884. Type: Aster lateriflorus (L.) Britton (= Aster divergens Aiton). Aster (sect. Genuint] B Homophylli Nees, Gen. Sp. Aster. 52. 1832. Aster sect. Homophylli (Nees) A. Gray, Synopt. Fil. 1(2):183. 1884. Lectotype (designated here): Aster diffusus Aiton (= Aster divergens Aiton = Aster lateriflorus [L.| Britton). Nees’s “Homophylli” group comprised 64 species that are dispersed through a number of sections in the current treatment. The selection of a lectotype is arbitrary, in- tended to be taxonomically non-intrusive. 270 PHYTOLOGIA volume 77(3):141-297 September 1994 Aster subsect. Leucanthi (Nees) A.G. Jones, Brittonia 32:235. 1980. Lectotype (Jones 1980a.): Aster simpler Willd. (= Aster lanceolatus Willd.). INCL: Symphyotrichum boreale (Torr. & Gray) Love & Love, S. bulla- tum (Klatt) Nesom, S. burgessi{ Britton) Nesom, S. carnerosanum (S. Wats.) Nesom, S. eulae (Shinners) Nesom, S. fontinale (Alexander) Nesom, S. lance- olatum (Willd.) Nesom, S. lateriflorum (L.) Love & Love, S. leone (Britton) Nesom, S. ontarione (Wieg.) Nesom, S. praealtum (Poir.) Nesom, S. race- mosum (Elliott) Nesom, S. schaffneri (S.D. Sundb. & A.G Jones) Nesom, S. tradescantz (L.) Nesom. c. Symphyotrichum subsect. Porteriani (Rydb.) Nesom, comb. nov. BA- SIONYM: Aster sp.-group Portertant Rydb., Fl. Colorado 352. 1906. Aster sect. Porteriani (Rydb.) A.G. Jones, Brittonia 32:235. 1980. Aster [subg. Aster sect. Dumosi] subsect. Porteriant (Rydb.) Semple, Phytolo- gia 58:429. 1985. Type: Aster porter: A. Gray. INCL: Symphyotrichum depauperatum (Fernald) Nesom, S. parviceps ( Bur- gess) Nesom, S. pilosum (Willd.) Nesom, S. portert (A. Gray) Nesom, S. priceae (Britton) Nesom. E. Symphyotrichum sect. Oxytripolium (DC.) Nesom, comb. nov. BA- SIONYM: Tripokum sect. Ozytripolium DC., Prodr. 5:253. 1836 (pro parte). Aster subg. Ozytripolium (DC.) Torr. & Gray, Fl. N. Amer. 2:161. 1841. Lectotype (Jones 1980a): Aster tenutfolius L. Gray (1880, 1884) referred the perennial species of sect. Ozytripolium ( Aster tenutfolius L., specifically) to subg. Orthomeris; in the same treatment, however, he formally maintained subg. Ozytripolium to include the annual species (i.e., A. subulatus). Tripolum subg. Astropolium Nutt., Trans. Amer. Philos. Soc., ser. 2, 7:295. 1840. Lectotype (following Sundberg 1986): Aster tenutfolius L. Aster sect. Heterastrum Benth. in Benth. & Hook., Gen. Pl. 2:273. 1873. Lectotype (designated here): Aster vahlii Gaud. Nesom: Review of Aster taxonomy 271 Fimbristima Rafin., Fl. Tellur. 2:46. 1836. [1837.]. Lectotype (designated here): Fimbristima squamata (Spr- eng.) Rafin. (= Aster squamatus (Spreng.] Hieron.). Mesoligus Rafin., Fl. Tellur. 2:44. 1836. [1837.]. Type: Mesoligus subulatus (Michx.) Rafin. (= Aster subulatus Michx.). Conyzanthus Tamamsch., Fl. U.R.S.S. 24:583. 1959. Type: Conyzanthus squamatus (Spreng.) Tamamsch. (= Aster squamatus (Spreng.] Hieron.). INCL: Symphyotrichum bahamense (Britton) Nesom, S. bracet (Britton ez Small) Nesom, S. divaricatum (Nutt.) Nesom, S. erpansum (Poepp. ez Spreng.) Nesom, S. glabrifolium (DC.) Nesom, S. graminifolium (Spreng.) Nesom, S. marti (Cabrera) Nesom, 5S. patagonicum (Cabrera) Nesom, S. peteroanum (Phil.) Nesom, S. potosinum (A. Gray) Nesom, S. regnellii (Baker) Nesom, S. squamatum (Spreng.) Nesom, S. subulatum (Michx.) Nesom, S. tenuifolium (L.) Nesom, S. vahliz (Gaud.) Nesom. F. Symphyotrichum sect. Conyzopsis (Torr. & Gray) Nesom, comb. nov. BASIONYM: Aster [subg. Ozytripolium] sect. Conyzopsis Torr. & Gray, Fl. N. Amer. 2:162. 1841. Aster subg. Conyzopsis (Torr. & Gray) A. Gray, Proc. Amer. Acad. Arts 16:99. 1880. Lectotype species (Jones 1980a): Aster brachyactis S.F. Blake (= Symphyotrichum ciliatum [Ledeb.| Nesom). Brachyactis Ledeb., Fl. Ross. 2:495. 1845. Type: Brachyactis ciliata (Ledeb.) Ledeb. INCL: Symphyotrichum ciliatum (Ledeb.) Nesom, S. frondosum (Nutt.) Nesom, S. laurentianum (Fernald) Nesom. G. Symphyotrichum sect. Occidentales (Rydb.) Nesom, comb. nov. BA- SIONYM: Aster sp.-group Occidentales Rydb., Fl. Colorado 352. 1906. Aster sect. Occidentales (Rydb.) A.G. Jones, Brittonia 32:235. 1980. Aster subsect. Occidentales (Rydb.) A.G. Jones, Phytologia 55:381. 1984. Type: Aster occidentalis (Nutt.) Torr. & Gray (= A. spathu- latus Lindl.). 272 PHYTOLOGIA volume 77(3):141-297 September 1994 Aster sp.-group Foliacei Rydb., Fl. Colorado 352. 1906. Aster subsect. Foliacet (Rydb.) A.G. Jones, Brittonia 32:235. 1980. Type: Aster foliaceus Lindl. er DC. Aster sp.-group Foliost Rydb., Fl. Rocky Mts. 882. 1922. Aster [sect. Alpigenit subsect. Homochaeta ser. Macrochaeti| subser. Fo- liost (Rydb.) Onno, Bibliot. Bot. 106:7. 1932. Type: Aster foliaceus Lindl. er DC. INCL: Symphyotrichum bracteolatum (Nutt.) Nesom, S. chilense (Nees) Nesom, S. cusickit (A. Gray) Nesom, S. foliaceum (DC.) Nesom, S. greatae (Parish) Nesom, S. hallii (A. Gray) Nesom, S. hendersoni (Fernald) Nesom, S. jessicae (Piper) Nesom, S. lentum (E. Greene) Nesom, S. molle (Rydb.) Ne- som, S. spathulatum (Lindl.) Nesom, S. subspicatum (Nees) Nesom, S. welshiu (Cronq.) Nesom. H. Symphyotrichum sect. Ascendentes (Rydb.) Nesom, comb. et stat. nov. BASIONYM: Aster sp.-group Ascendentes Rydb., Fl. Colorado 352, 354. 1906. Aster subg. Ascendentes (Rydb.) Semple [nom. illeg., see Lamboy 1986], Phytologia 58:430. 1985. Type: Aster ascendens Lindl. Virgulaster Semple [nom. illeg., see Lamboy 1986], Phytologia 58:430. 1985. Type: Aster ascendens Lindl. INCL: Symphyotrichum ascendens (Lindl). Nesom, S. defoliatum (Parish) Nesom (= Aster bernardinus Hall). 2. Symphyotrichum subg. Virgulus (Rafin.) Nesom, comb. nov. BA- SIONYM: Virgulus Rafin., Fl. Tellur. 2:46. 1836 [1837]. Aster subg. Virgulus (Rafin.) A.G. Jones, Brittonia 32:233. 1980. Type: Virgulus concolor (L.) Rafin. (= Aster concolor L.). Virgaria Rafin. ez DC. [pro syn.|], Prodr. 5:243. 1836. Type: Virgaria concolor (L.) Rafin. ex DC. (= Aster concolor L.). Lasallea E. Greene {nom. superfi. illeg.|, Leafl. Bot. Observ. Crit. 1:5. 1903. (not Lasallia Merat 1821.). Type: Lasallea sericea (Vent.) E. Greene (= Aster serv- ceus Vent.) Nesom: Review of Aster taxonomy 273 A. Symphyotrichum sect. Grandiflori (Torr. & Gray) Nesom, comb. nov. BASIONYM: Aster sect. Grandiflori Torr. & Gray, Fl. N. Amer. 2:142. 1841. Lasallea sect. Grandiflorae (Torr. & Gray) Semple & Brouillet, Amer. J. Bot. 67:1022. 1980. Virgulus sect. Grandiflorae (Torr. & Gray) Reveal & Keener, Taxon 30:649. 1981. Type: Aster grandiflorus L. Aster sect. Glandulost A. Gray, Synopt. Fl. 1(2):177. 1884. Lectotype (designated here): Aster grandtflorus L. Gray broadened his sect. Grandiflori of 1841 and gave it a different name (sect. Glandulosi), but six of the eight species included in the latter are virgu- loid species. a. Symphyotrichum subsect. Grandiflori (Torr. & Gray) Nesom, comb. et stat. nov. BASIONYM: Aster sect. Grandiflori Torr. & Gray, Fl. N. Amer. 2:142. 1841. Type: Aster grandiflorus L. INCL: Symphyotrichum grandiflorum (L.) Nesom. b. Symphyotrichum subsect. Polyligulae (Semple & Brouillet) Nesom, comb. nov. BASIONYM: Lasallea [sect. Grandiflorae] subsect. Polyligu- lae Semple & Brouillet, Amer. J. Bot. 67:1023. 1980. Type: Aster novae-angliae L. Aster sp.-group Oblongifolis Rydb., Fl. Colorado 351. 1906. Aster sect. Oblongifoli: (Rydb.) A.G. Jones, Brittonia 32:233. 1980. Virgulus sect. Oblongifoli (Rydb.) Reveal & Keener, Taxon 30:649. 1981. Type: Aster oblongifolius Nutt. INCL: Symphyotrichum campestre (Nutt.) Nesom, S. fendlert (A. Gray) Nesom, S. novae-angliae (L.) Nesom, S. oblongtfolium (Nutt.) Nesom, S. yuko- nense (Cronq). Nesom. c. Symphyotrichum subsect. Mexicanae Nesom, subsect. nov. Type: Symphyotrichum moranense (Kunth) Nesom. Foliis parvis sessilibus trinervatis, capitulis solitariis, flos- culis radii plerumque albis, et distributione in Mexici distinc- tus. 274 PHYTOLOGIA volume 77(3):141-297 September 1994 INCL: Symphyotrichum gypsophilum (B.L. Turner) Nesom, S. hintoniw (Nesom) Nesom, S. moranense, S. trilineatum (Sch.-Bip. ez Klatt) Nesom. d. Symphyotrichum subsect. Brachyphylli (Torr. & Gray) Nesom, comb. nov. BASIONYM: Aster sect. Brachyphylli Torr. & Gray, Fl. N. Amer. 2:114. 1841. Lasallea [sect. Grandiflorae| subsect. Brachyphyllae (Torr. & Gray) Semple & Brouillet, Amer. J. Bot. 67:1023. 1980. Type: Aster walter: Alexander. INCL: Symphyotrichum adnatum (Nutt.) Nesom, S. walter: (Alexander) Nesom. B. Symphyotrichum sect. Ericoidei (Torr. & Gray) Nesom, comb. nov. BASIONYM: Aster sect. Ericotde: Torr. & Gray, Fl. N. Amer. 2:123. 1841. Aster {[sect. Homophylli] subsect. Ericoidei A. Gray, Synopt. Fl. 1(2):184. 1884. Virgulus sect. Ericoidet (Torr. & Gray) Reveal & Keener, Taxon 30:649. 1981. [See comments in Jones 1982, 1983d.]. Type: Aster ericotdes L. Aster (sect. Homophylli| subsect. Multiflori A. Gray, Synopt. Fl. 1(2):185. 1884. Aster sect. Multiflori(A. Gray) R.A. Nelson, Rhodora 35:323. 1933. Lasallea sect. Multiflori (A. Gray) Semple & Brouillet, Amer. J. Bot. 67:1022. 1980. Type: Aster ertcordes L. Aglotoma Rafin., Fl. Tellur. 2:44. 1836. [1837.]. Type: Aster ericoides L. Rafinesque cited as the type “Aster multiflorus M. alia sp.” What he meant by the authority citation is not clear, but the A. multiflorus in general use at the time seems to have been that with the name proposed by Solander, which is a synonym of Aster ericozdes. INCL: Symphyotrichum ericoides (L.) Nesom, S. falcatum (Lindl.) Nesom. C. Symphyotrichum sect. Patentes (Torr. & Gray) Nesom, comb. nov. BASIONYM: Aster sect. Patentes Torr. & Gray, Fl. N. Amer. 2:114. 1841. Virgulus sect. Patentes (Torr. & Gray) Reveal & Keener, Taxon 30:650. 1981. Type: Aster patens Aiton. INCL: Symphyotrichum georgianum (Alexander) Nesom, S. patens (Aiton) Nesom, S. phlogifolium (Muhl. ez Willd.) Nesom (see R. Jones 1983, 1992). Nesom: Review of Aster taxonomy 275 D. Symphyotrichum sect. Concolores (Torr. & Gray) Nesom, comb. nov. BASIONYM: Aster sect. Concolores Torr. & Gray, Fl. N. Amer. 2:113. 1841. Lasallea |sect. Lasallea| subsect. Concolores (Torr. & Gray) Semple & Brouillet, Amer. J. Bot. 67:1022. 1980. Type: Aster concolor L. Virgulus [sect. Virgulus] subsect. Lasallea (E. Greene) Semple [comb. illeg.|, Phytologia 58:431. 1985. Lasallea E. Greene [nom. superfl. illeg.|, Leafl. Bot. Observ. Crit. 1:5. 1903. (not Lasallia Merat 1821.). Type: Lasallea sericea ( Vent.) E. Greene (= Aster serz- ceus Vent.). Aster sect. Sericeo-concolores A. Gray, Synopt. Fl. 1(2):179. 1884. Lectotype (designated here): Aster concolor L. INCL: Symphyotrichum concolor (L.) Nesom, S. lucayanum (Britton) Ne- som, S. pratense (Rafin.) Nesom, S. sericeum (Vent.) Nesom. Species of Symphyotrichum: 1. Symphyotrichum adnatum (Nutt.) Nesom, comb. nov. BASIONYM: Aster adnatus Nutt., J. Acad. Nat. Sci. Philad. 7:82. 1834. Lasallea ad- nata (Nutt.) Semple & Brouillet, Amer. J. Bot. 67:1923. 1980. Virgulus adnatus (Nutt.) Reveal & Keener, Taxon 30:650. 1931. 2. Symphyotrichum anomalum (Engelm.) Nesom, comb. nov. BASIO- NYM: Aster anomalus Engelm. in Torr. & Gray, Fl. N. Amer. 2:503. 1843. 3. Symphyotrichum anticostense (Fernald) Nesom, comb. nov. BA- SIONYM: Aster anticostensts Fernald, Rhodora 17:16. 1915. Aster gaspensis Victorin, Contr. Lab. Bot. Univ. Montreal 20:3. 1932. Aster longtfolius Lam. var. villicaulis A. Gray, Synopt. Fl. 1(2):189. 1884. Aster novi-belgit L. var. villicaulis (A. Gray) Boivin, Natu- raliste Canad. 94:645. 1967. Aster johannensis Fernald, Rhodora 17:12. 1915. Aster novt-belgiz L. subsp. johannensis (Fernald) A.G. Jones, Phytologia 55:384. 1984. Aster novi-belgit L. var. johannensis (Fernald) A.G. Jones, Phytolo- gia 63:132. 1987. 276 PHY TOL OGTA volume 77(3):141-297 September 1994 4. Symphyotrichum ascendens (Lindl.) Nesom, comb. nov. BASIONYM: Aster ascendens Lindl. in Hook., Fl. Bor.-Amer. 2:8. 1834. Virgulaster ascendens (Lindl.) Semple [nom. illeg.], Phytologia 58:431. 1985. 5. Symphyotrichum bahamense (Britton) Nesom, comb. nov. BASIO- NYM: Aster bahamensis Britton, Bull. Torrey Bot. Club 41:14. 1914. Aster subulatus Michx. var. elongatus Bosserd., Taxon 19:250. 1970. 6. Symphyotrichum boreale (Torr. & Gray) Love & Love, Taxon 31:358. 1982. BASIONYM: Aster laziflorus Lindl. var. borealis Torr. & Gray, Fl. N. Amer. 2:138. 1841. Aster borealis (Torr. & Gray) Provanch., Fl. Canad. 1:308. 1862. Aster junctformis Rydb., Bull. Torrey Bot. Club 37:142. 1910. 7. Symphyotrichum bracei (Britton ez Small) Nesom, comb. nov. BA- SIONYM: Aster bracei Britton ez Small, Fl. Miam: 190, 200. 1913. Aster tenutfolius L. var. aphyllus R. Long, Rhodora 72:40. 1970. 8. Symphyotrichum bracteolatum (Nutt.) Nesom, comb. nov. BA- SIONYM: Aster bracteolatus Nutt., Trans. Amer. Philos. Soc., ser. 2, 7:293. 1841. Aster eatonit (A. Gray) T.J. Howell, Fl. N.W. Amer. 310. 1900. BA- SIONYM: Aster foliaceus Lindl. ez DC. var. eatontt A. Gray, Syn- opt. Fl. 2(1):194. 1884. © . Symphyotrichum bullatum (Klatt) Nesom, comb. nov. BASIONYM: Aster bullatus Klatt, Ann. Naturhist. Mus. Vienna 9:359. 1894. Aster jalapensts Fernald, Proc. Amer. Acad. Arts 35:572. 1900. 10. Symphyotrichum burgessii (Britton) Nesom, comb. nov. BASIONYM: Aster burgess Britton, Bull. Torrey Bot. Club 41:14. 1914. 11. Symphyotrichum campestre (Nutt.) Nesom, comb. nov. BASIONYM: Aster campestris Nutt., Trans. Amer. Philos. Soc., ser. 2, 7:293. 1841. Virgulus campestris (Nutt.) Reveal & Keener, Taxon 30:649. 1981. a. Symphyotrichum campestre (Nutt.) Nesom var. bloomeri (A. Gray) Nesom, comb. nov. BASIONYM: Aster bloomer: A. Gray, Proc. Amer. Acad. Arts 6:539. 1865. Aster campestris Nutt. var. bloomer: (A. Gray) A. Gray, Synopt. Fl. 1(2):178. 1884. Virgulus campestris( Nutt.) Reveal & Keener var. bloomer: (A. Gray) Reveal & Keener, Taxon 30:649. 1981. Nesom: Review of Aster taxonomy 277 b. Symphyotrichum campestre (Nutt.) Nesom var. campestre 12. Symphyotrichum carnerosanum (S. Wats.) Nesom, comb. nov. BA- SIONYM: Aster carnerosanus S. Wats., Proc. Amer. Acad. Arts 26:139. 1891. 13. Symphyotrichum chilense (Nees) Nesom, comb. nov. BASIONYM: .Aster chilensis Nees, Gen. Sp. Aster. 123. 1832. a. Symphyotrichum chilense (Nees) Nesom var. chilense b. Symphyotrichum chilense (Nees) Nesom var. invenustum (E. Greene) Nesom, comb. nov. BASIONYM: Aster invenustus E. Greene, Man. Bay Reg. 179. 1894. Aster chilensts Nees var. tn- venustus (E. Greene) Jepson, Man. Fl. Pl. Cahf. 1047. 1925. c. Symphyotrichum chilense (Nees) Nesom var. medium (Jepson) Nesom, comb. nov. BASIONYM: Aster chilensis Nees var. medius Jepson, Man. Fl. Pl. Calif. 1047. 1925. 14. Symphyotrichum ciliatum (Ledeb.) Nesom, comb. nov. BASIONYM: Erigeron ciliatus Ledeb., Ic. Pl. 24. 1829. Brachyactis ciliata (Ledeb.) Ledeb., Fl. Ross. 2:495. 1846. Aster brachyactis S.F. Blake [nom. nov.|, Contr. U.S. Natl. Herb. 25:564. 1925. (not Aster cilatus Walter 1788.; not Eurybia ciliata Benth. 1837.). Tripolium angustatum Lindl. in Hook., Fl. Bor.-Amer. 2:15. 1834. Aster angustatus (Lindl.) Torr. & Gray, Fl. N. Amer. 2:162. 1841. Brachyactis ciliata (Ledeb.) Ledeb. subsp. angustata (Lindl.) A.G. Jones, Phytologia 55:376. 1984. 15. Symphyotrichum ciholatum (Lindl.) Love & Love, Taxon 31:359. 1982. BASIONYM: Aster ciliolatus Lindl. in Hook., Fl. Bor.-Amer. 2:9. 1834. a. Symphyotrichum ciliolatum (Lindl.) Love & Love var. ctliolatum b. Symphyotrichum ciliolatum (Lindl.) Love & Love var. coma- tum (Fernald) Nesom, comb. nov. BASIONYM: Aster lindleyanus Torr. & Gray var. comatus Fernald, Rhodora 6:142. 1904. Aster ciliolatus Lindl. in Hook. var. comatus (Fernald) A.G. Jones, Phy- tologia 55:379. 1984. c. Symphyotrichum ciliolatum (Lindl.) Love & Love var. mac- callae (Rydb.) Nesom, comb. nov. BASIONYM: Aster maccallae Rydb., Bull. Torrey Bot. Club 37:138. 1910. Aster ciltolatus Lindl. tn Hook. var. maccallae (Rydb.) A.G. Jones, Phytologia 55:380. 1984. 278 16. PHYTOLOGIA volume 77(3):141-297 September 1994 d. Symphyotrichum ciliolatum (Lindl.) Love & Love var. wilsonii * (Rydb.) Nesom, comb. nov. BASIONYM: Aster wilsoni Rydb., Bull. Torrey Bot. Club 37:138. 1910. Aster cilolatus Lindl. in Hook. var. wilsoni (Rydb.) A.G. Jones, Phytologia 55:379. 1984. Symphyotrichum concolor (L.) Nesom, comb. nov. BASIONYM: Aster concolor L., Sp. Pl., (ed. 2) 2:874. 1763. Lasallea concolor (L.) Semple & Brouillet, Amer. J. Bot. 67:1022. 1980. Virgulus concolor (L.) Reveal & Keener, Taxon 30:649. 1981. 17. Symphyotrichum cordifolium (L.) Nesom, coms. nov. BASIONYM: 18. Aster cordtfolius L., Sp. Pl. 2:875. 1753. a. Symphyotrichum cordifolium (L.) Nesom var. cordifolium b. Symphyotrichum cordifolium (L.) Nesom var. furbishiae (Fer- nald) Nesom, comb. nov. BASIONYM: Aster cordifolius L. var. furbishiae Fernald, Proc. Portland Soc. Nat. Hist. 2:129. 1897. c. Symphyotrichum cordifolium (L.) Nesom var. lanceolatum (Porter) Nesom, comb. nov. BASIONYM: Aster cordifolius L. var. lanceolatus Porter, Bull. Torrey Bot. Club 16:68. 1889. Aster lowrieanus Porter var. lanceolatus (Porter) Porter, Bull. Torrey Bot. Club 21:121. 1894. Aster cordtfolius L. var. inctsus Britton, Bull. Torrey Bot. Club 19:224. 1892. Aster lowrieanus Porter var. inctsus (Britton) Porter, Bull. Torrey Bot. Club 21:121. 1894. d. Symphyotrichum cordifolium (L.) Nesom var. moratum (Shin- ners) Nesom, comb. nov. BASIONYM: Aster finkii Rydb. var. moratus Shinners, Amer. Midl. Nat. 26:407. 1941. Aster cordi- folius L. var. moratus (Shinners) Shinners, Castanea 10:65. 1945. e. Symphyotrichum cordifolium (L.) Nesom var. polycephalum ~ (Porter) Nesom, comb. nov. BASIONYM: Aster cordifolius L. var. polycephalus Porter, Bull. Torrey Bot. Club 21:120. 1894. f. Symphyotrichum cordifolium (L.) Nesom var. racemiflorum (Fernald) Nesom, comb. nov. BASIONYM: Aster cordifolius L. var. racemiflorus Fernald, Rhodora 19:155. 1917. Symphyotrichum crenifolium (Fernald) Nesom, comb. nov. BA- SIONYM: Aster crenifolius (Fernald) Cronq., Bull. Torrey Bot. Club 74:143. 1947. Aster foliaceus Lindl. er DC. var. crentfolius Fernald, Rhodora 17:15. 1915. 19. Symphyotrichum cusickii (A. Gray) Nesom, comb. nov. BASIONYM: Aster cusickit A. Gray, Proc. Amer. Acad. Arts 16:99. 1880. Aster’ Nesom: Review of Aster taxonomy 279 20. al. 22. 23. foliaceus var. cusickit (A. Gray) Crong., Amer. Midl. Natur. 29:443. 1943. Symphyotrichum defoliatum (Parish) Nesom, comb. nov. BASIO- NYM: Aster defoliatus Parish, Bot. Gaz. (Crawfordsville) 38:461. 1904. Aster bernardinus Hall, Univ. Calif. Pub. Bot. 3:79. 1907. Virgulaster bernardinus (Hall) Semple (nom. illeg.], Phytologia 58:431. 1985. Symphyotrichum depauperatum (Fernald) Nesom, comb. nov. BA- SIONYM: Aster depauperatus Fernald [nom. nov.|, Rhodora 10:94. 1908. (not Aster pusillus Hornem.). Aster ericoides L. var. depauperatus Porter (nom. illeg., a substitution for Gray’s var. pusillus, see Jones 1984], Mem. Torrey Bot. Club 5:323. 1894. Aster ericoides L. var. pusillus A. Gray, Synopt. Fl. 1(2):184. 1882. Aster pilosus Willd. var. pustllus (A. Gray) A.G. Jones, Phytologia 55:382. 1984. Symphyotrichum divaricatum (Nutt.) Nesom, comb. nov. BASIO- NYM: Tripohum divaricatum Nutt., Trans. Amer. Philos. Soc. 7:296. 1841. Aster divaricatus (Nutt.) Torr. & Gray [nom. illeg.], Fl. N. Amer. 2:163. 1841. (not Aster divaricatus L. 1753.). Aster neomezicanus Wooton & Standl., Contr. U.S. Natl. Herb. 16:187. 1913. Aster subulatus Michx. var. ligulatus Shinners, Field & Lab. 21:159. 1953. Symphyotrichum drummondii (Lindl.) Nesom, comb. nov. BA- SIONYM: Aster drummondi Lindl. in Hook., Comp. Bot. Mag. 1:97. 1835. a. Symphyotrichum drummondi (Lindl.) Nesom var. drummondii b. Symphyotrichum drummondii (Lindl.) Nesom var. parviceps (Shinners) Nesom, comb. nov. BASIONYM: Aster teranus Burgess var. parviceps Shinners, Field & Lab. 21:156. 1953. Aster drum- mondu Lindl. in Hook. subsp. parviceps (Shinners) A.G. Jones, Phy- tologia 55:381. 1984. Aster drummondii Lindl. in Hook. var. par- viceps (Shinners) A.G. Jones, Phytologia 63:131. 1987. c. Symphyotrichum drummondii (Lindl.) Nesom var. texanum (Burgess) Nesom, comb. nov. BASIONYM: Aster teranus Burgess in Small, Fl. Southeast. U.S. 1214, 1339. 1903. Aster drummondi Lindl. in Hook. subsp. teranus (Burgess) A.G. Jones, Phytologia 280 PHYTOLOGIA volume 77(3):141-297 September 1994 55:380. 1984. Aster drummondi Lindl. in Hook. var. tezanus (Burgess) A.G. Jones, Phytologia 63:131. 1987. 24. Symphyotrichum dumosum (L.) Nesom, comb. nov. BASIONYM: Aster dumosus L., Sp. Pl. 2:873. 1753. a. Symphyotrichum dumosum (L.) Nesom var. dodgei (Fernald) Nesom, comb. nov. BASIONYM: Aster dumosus L. var. dodgez Fernald, Rhodora 11:31. 1909. b. Symphyotrichum dumosum (L.) Nesom var. dumosum Aster coridtfolius Michx., Fl. Bor.-Amer. 2:112. 1803. Aster du- mosus L. var. coridifolius (Michx.) Torr. & Gray, Fl. N. Amer. 2:128. 1841. c. Symphyotrichum dumosum (L.) Nesom var. gracilipes (Wieg.) Nesom, comb. nov. BASIONYM: Aster dumosus L. var. gracilipes Wieg., Rhodora 30:166. 1928. d. Symphyotrichum dumosum (L.) Nesom var. pergracile (Wieg.) Nesom, comb. nov. BASIONYM: Aster dumosus L. var. pergracilis Wieg., Rhodora 30:166. 1928. e. Symphyotrichum dumosum (L.) Nesom var. strictior (Torr. & Gray) Nesom, comb. nov. BASIONYM: Aster dumosus L. var. strictior Torr. & Gray, Fl. N. Amer. 2:128. 1841. f. Symphyotrichum dumosum (L.) Nesom var. subulifolium (Torr. & Gray) Nesom, comb. nov. BASIONYM: Aster dumosus L. var. subulifolius Torr. & Gray, Fl. N. Amer. 2:128. 1841. 25. Symphyotrichum elliottii (Torr. & Gray) Nesom, comb. nov. BA- SIONYM: Aster elliott: Torr. & Gray, Fl. N. Amer. 2:140. 1841. Aster punzceus L. subsp. elliottit (Torr. & Gray) A.G. Jones, Phytologia 55:384. 1984. Aster puntceus L. var. elliotts: (Torr. & Gray) A.G. Jones, Phy- tologia 63:132. 1987. 26. Symphyotrichum ericoides (L.) Nesom, comb. nov. BASIONYM: Aster ericoides L., Sp. Pl. 2:875. 1753. Lasallea ericoides (L.) Semple & Brouillet, Amer. J. Bot. 67:1023. 1980. Virgulus ertcoides (L.) Reveal & Keener, Taxon 30:649. 1981. a. Symphyotrichum ericoides (L.) Nesom var. ertcotdes Aster multiflorus Sol. ez Aiton, Hort. Kew. 3:203. 1789. b. Symphyotrichum ericoides (L.) Nesom var. pansum (S.F. Blake) Nesom, comb. nov. BASIONYM: Aster multiflorus Sol. ez Aiton var. pansus S.F. Blake, Rhodora 30:227. 1928. Aster pansus (S.F. Nesom: Review of Aster taxonomy 281 Blake) Cronq., Leafl. W. Bot. 6:45. 1950. Aster ericotdes L. var. pansus (S.F. Blake) Boivin, Naturaliste Canad. 89:70. 1962. Virgu- lus ericoides (L.) Reveal & Keener var. pansus (S.F. Blake) Reveal & Keener, Taxon 30:649. 1981. c. Symphyotrichum ericoides (L.) Nesom var. prostratum (Kuntze) Nesom, comb. nov. BASIONYM: Aster multiflorus Sol. ez Aiton var. prostratus Kuntze, Rev. Gen. 1:313. 1891. Aster ericozdes L. var. prostratus (Kuntze) S.F. Blake, Rhodora 32:138. 1930. d. Symphyotrichum ericoides (L.) Nesom var. stricticaule (Torr. & Gray) Nesom, comb. nov. BASIONYM: Aster multiflorus Sol. ez Aiton var. stricticaulis Torr. & Gray, Fl. N. Amer. 2:125. 1841. Aster ertcoides L. var. stricticaulis (Torr. & Gray) F.C. Gates, Trans. Kansas Acad. Sci. 42:138. 1940. 27. Symphyotrichum eulae (Shinners) Nesom, comb. nov. BASIONYM: Aster eulae Shinners, Field & Lab. 18:35. 1950. 28. Symphyotrichum expansum (Poepp. ez Spreng.) Nesom, comb. nov. BASIONYM: Erigeron ezpansus Poepp. ez Spreng., Syst. Veg. 3:518. 1826. Aster inconspicuus Less. in Schlecht. & Cham., Linnaea 5:143. 1830. Aster madrensis M.E. Jones, Contr. West. Bot. 12:43. 1908. Tripolium subulatum (L.) Nees var. parviflorum Nees, Gen. Sp. Aster. 157. 1832. Tripolium subulatum (L.) Nees var. cubensis DC., Prodr. 5:254. 1836. Aster subulatus Michx. var. cubensis (DC.) Shinners, Field & Lab. 21:161. 1953. 29. Symphyotrichum falcatum (Lindl.) Nesom, comb. nov. BASIONYM: Aster falcatus Lindl. in Hook., Fl. Bor.-Amer. 2:12. 1834. Lasallea fal- cata (Lindl.) Semple & Brouillet, Amer. J. Bot. 67:1023. 1980. Virgulus falcatus (Lindl.) Reveal & Keener, Taxon 30:649. 1981. a. Symphyotrichum falcatum (Lindl.) Nesom var. falcatum b. Symphyotrichum falcatum (Lindl.) Nesom var. commutatum (Torr. & Gray) Nesom, comb. nov. BASIONYM: Aster multiflorus Sol. ex Aiton var. commutatus Torr. & Gray, Fl. N. Amer. 2:125. 1841. Aster falcatus Lindl. var. commutatus (Torr. & Gray) A.G. Jones, Phytologia 63:131. 1987. Aster nahanniensis W.J. Cody, Naturaliste Canad. 101:888. 1974. 282 PHYTOLOGIA volume 77(3):141-297 September 1994 c. Symphyotrichum falcatum (Lindl.) Nesom var. crassulum (Rydb.) Nesom, comb. nov. BASIONYM: Aster crassulus Rydb., Bull. Tor- rey Bot. Club 28:504. 1901. Aster falcatus Lindl. var. crassulus (Rydb.) Cronq., Bull. Torrey Bot. Club 74:144. 1947. 30. Symphyotrichum fendleri (A. Gray) Nesom, comb. nov. BASIONYM: Aster fendlert A. Gray, Mem. Amer. Acad. Arts II, 4:66. 1849. Virgulus fendlert (A. Gray) Reveal & Keener, Taxon 30:649. 1981. 31. Symphyotrichum firmum (Nees) Nesom, comb. nov. BASIONYM: Aster firmus Nees, Synops. Ast. Herb. 25. 1818. Aster puniceus L. subsp. firmus (Nees) A.G. Jones, Phytologia 55:384. 1984. Aster lucidulus (A. Gray) Wieg., Rhodora 26:4. 1924. 32. Symphyotrichum foliaceum (DC.) Nesom, comb. nov. BASIONYM: Aster foliaceus Lindl. ex DC., Prodr. 5:228. 1836. a. Symphyotrichum foliaceum (DC.) Nesom var. apricum (A. Gray) Nesom, comb. nov. BASIONYM: Aster foliaceus Lindl. ez DC. var. apricus A. Gray, Synopt. Fl. 1(2):193. 1884. b. Symphyotrichum foliaceum (DC.) Nesom var. canbyi (A. Gray) Nesom, comb. nov. BASIONYM: Aster foliaceus Lindl. ex DC. var. canby: A. Gray, Synopt. Fl. 1(2):193. 1884. c. Symphyotrichum foliaceum (DC.) Nesom var. foliaceum d. Symphyotrichum foliaceum (DC.) Nesom var. parryi (D.C. Eat.) Nesom, comb. nov. BASIONYM: Aster ascendens Lindl. in Hook. var. parryi D.C. Eat., Bot. King Exp. 139. 1871. Aster fo- liaceus Lindl. ez DC. var. parryi (D.C. Eat.) A. Gray, Synopt. Fl. 1(2):193. 1884. 33. Symphyotrichum fontinale (Alexander) Nesom, comb. nov. BA- SIONYM: Aster fontinalis Alexander in Small, Man. Southeast. Fl. 1382, 1509. 1933. 34. Symphyotrichum frondosum (Nutt.) Nesom, comb. nov. BASIONYM: Tripohum frondosum Nutt., Trans. Amer. Philos. Soc., ser. 2, 7:296. 1840. Aster frondosus (Nutt.) Torr. & Gray, Fl. N. Amer. 2:165. 1841. Brachyactis frondosa (Nutt.) A. Gray, Proc. Amer. Acad. Arts 8:647. 1873. 35. Symphyotrichum georgianum (Alexander) Nesom, comb. nov. BA- SIONYM: Aster georgianus Alexander in Small, Man. Southeast. FI. 1381, 1509. 1933. Virgulus patens (Aiton) Reveal & Keener var. geor- gianus (Alexander in Small) Reveal & Keener, Taxon 30:649. 1981. Nesom: Review of Aster taxonomy 283 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. Symphyotrichum glabrifolium (DC.) Nesom, comb. nov. BASIONYM: Erigeron glabrifolius DC., Prodr. 5:287. 1836. Aster glabrifolius (DC.) Reiche, Anales Univ. Chile 109:337. 1901. Symphyotrichum graminifolium (Spreng.) Nesom, comb. nov. BA- SIONYM: Conyza graminifolia Spreng., Syst. Veg., (ed. 16) 3:515. 1826. Aster squamatus (Spreng.) Hieron. in Sod. var. graminifolius (Spreng.) Hieron. zn Sod., Bot. Jahrb. Syst. 29:19. 1900. Conyzanthus gramini- folius (Spreng.) Tamamsch., Fl. U.R.S.S. 25:186. 1959. Symphyotrichum grandiflorum (L.) Nesom, comb. nov. BASIONYM: Aster grandiflorus L., Sp. Pl. 2:887. 1753. Lasallea grandiflora (L.) Semple & Brouillet, Amer. J. Bot. 67:1022. 1980. Virgulus grandiflorus (L.) Reveal & Keener, Taxon 30:649. 1981. Symphyotrichum greatae (Parish) Nesom, comb. nov. BASIONYM: Aster greatae Parish, Bull. S. Calif. Acad. 1:15. 1902. Symphyotrichum gypsophilum (B.L. Turner) Nesom, comb. nov. BA- SIONYM: Aster gypsophilus B.L. Turner, Southw. Nat. 19:123. 1974. Symphyotrichum hallii (A. Gray) Nesom, comb. nov. BASIONYM: Aster halla A. Gray, Synopt. Fl. 1(2):191. 1884. Aster chilensts Nees subsp. hallit (A. Gray) Cronq., Amer. Midl. Natural. 29:462. 1948. Symphyotrichum hendersonii (Fernald) Nesom, comb. nov. BA- SIONYM: Aster hendersonii Fernald, Bull. Torrey Bot. Club 22:273. 1895. Aster cusickit A. Gray var. lyallit A. Gray, Synopt. Fl. 1(2):195. 1884. Aster foliaceus Lindl. ez DC. var. lyallii (A. Gray) Cronq., Amer. Midl. Nat. 29:443. 1943. Symphyotrichum hintonii (Nesom) Nesom, comb. nov. BASIONYM: Aster hintonis Nesom, Phytologia 67:342. 1989. Symphyotrichum jessicae (Piper) Nesom, comb. nov. BASIONYM: Aster jessicae Piper, Erythea 6:30. 1878. Symphyotrichum laeve (L.) Love & Love, Taxon 31:359. 1982. BA- SIONYM: Aster laevis L., Sp. Pl. 2:876. 1753. a. Symphyotrichum laeve (L.) Love & Love var. concinnum (Willd.) Nesom, comb. nov. BASIONYM: Aster concinnus Willd., Enum. Hort. Berol. 2:884. 1809. Aster laevis L. var. concinnus (Willd.) House, Bull. N.Y. State Mus. 243-244:15. 1923. 284 PHY TOLOGGIA volume 77(3):141-297 September 1994 b. Symphyotrichum laeve (L.) Love & Love var. geyeri (A. Gray) Nesom, comb. nov. BASIONYM: Aster laevis L. var. geyeriz A. Gray, Synopt. Fl. 1(2):183. 1884. Aster geyert (A. Gray) Howell, Fl. N.W. Amer. 1:308. 1900. Aster laevis L. var. guadalupensis A.G. Jones, Sida 9:173. 1981. c. Symphyotrichum laeve (L.) Love & Love var. laeve d. Symphyotrichum laeve (L.) Love & Love var. purpuratum _ (Nees) Nesom, comb. nov. BASIONYM: Aster purpuratus Nees, Gen. Sp. Aster. 118. 1832. Aster laevis L. var. purpuratus (Nees) A.G. Jones, Phytologia 55:377. 1984. 46. Symphyotrichum lanceolatum (Willd.) Nesom, comb. nov. BA- SIONYM: Aster lanceolatus Willd., Sp. Pl. 3:2050. 1803. A. Symphyotrichum lanceolatum (Willd.) Nesom subsp. hesperium (A. Gray) Nesom, comb. nov. BASIONYM: Aster lanceolatus Willd. subsp. hesperius (A. Gray) Semple & Chmielewski, Canad. J. Bot. 65:1060. 1987. a. Symphyotrichum lanceolatum (Willd.) Nesom var. hesperium (A. Gray) Nesom, comb. nov. BASIONYM: Aster hesperius A. Gray, Synopt. Fl. 1(2):192. 1884. Aster foliaceus Lindl. ez DC. var. hesperius (A. Gray) Jepson, Man. Fl. Pi. Calif. 1047. 1925. Symphyotrichum hesperium (A. Gray) Love & Love, Taxon 31:359. 1982. Aster hespertus A. Gray var. wootoni E. Greene, Bull. Torrey Bot. Club 25:119. 1898. Aster wootoni (E. Greene) E. Greene, Leafl. Bot. Observ. Crit. 1:146. 1905. B. Symphyotrichum lanceolatum (Willd.) Nesom subsp. lanceolatum Aster lanceolatus Willd. subsp. simplez (Willd.) A.G. Jones, Phy- tologia 55:383. 1984. Aster simpler Willd., Enum. Hort. Berol. 2:887. 1809. Symphyotrichum simplex (Willd.) Love & Love, Taxon 31:359. 1982. Aster lanceolatus Willd. var. simplez (Willd.) A.G. Jones, Phytologia 63:132. 1987. b. Symphyotrichum lanceolatum ( Willd.) Nesom var. hirsuticaule (Semple & Chmielewski) Nesom, comb. nov. BASIONYM: Aster lanceolatus Willd. var. hirsuticaulis Semple & Chmielewski, Canad. J. Bot. 65:1058. 1987. c. Symphyotrichum lanceolatum (Willd.) Nesom var. interior (Wieg.) Nesom, comb. nov. BASIONYM: Aster interior Wieg.,’ Rhodora 33:35. 1933. Aster lanceolatus Willd. var. interior (Wieg.) Nesom: Review of Aster taxonomy 285 Semple & Chmielewski, Canad. J. Bot. 65:1058. 1987.; A.G. Jones, Phytologia 63:132. 1987. Aster lanceolatus Willd. subsp. interior (Wieg.) A.G. Jones, Phytologia 55:383. 1984. d. Symphyotrichum lanceolatum (Willd.) Nesom var. lanceolatum e. Symphyotrichum lanceolatum (Willd.) Nesom var. latifolium (Semple & Chmielewski) Nesom, comb. nov. BASIONYM: Aster lanceolatus Willd. var. latifolius Semple & Chmielewski, Canad. J. Bot. 65:1060. 1987. 47. Symphyotrichum latertflorum (L.) Love & Love, Taxon 31:359. 1982. BASIONYM: Solidago lateriflorus L., Sp. Pl. 2:879. 1753. Aster lateri- florus (L.) Britton, Trans. New York Acad. Sci. 9:11. 1884. a. Symphyotrichum lateriflorum (L.) Love & Love var. angusti- folium (Wieg.) Nesom, comb. nov. BASIONYM: Aster lateriflorus (L.) Britton var. angustifolius Wieg., Rhodora 30:174. 1928. b. Symphyotrichum lateriflorum (L.) Love & Love var. flagellare (Shinners) Nesom, comb. nov. BASIONYM: Aster lateriflorus (L.) Britton var. flagellarts Shinners, Field & Lab. 21:157. 1953. Aster lateriflorus (L.) Britton var. indutus Shinners, Field & Lab. 21:158. 1953. c. Symphyotrichum lateriflorum (L.) Love & Love var. hirsuti- caule (DC.) Nesom, comb. nov. BASIONYM: Aster hirsuticaulis Lindl. ez DC., Prodr. 5:242. 1836. Aster lateriflorus (L.) Britton var. hirsuticaulis (DC.) Porter, Mem. Torrey Bot. Club 5:324. 1894. d. Symphyotrichum lateriflorum (L.) Love & Love var. horizon- tale (Desf.) Nesom, comb. nov. BASIONYM: Aster horizontalis Desf., Cat. Pl. Hort. Reg. Paris. (ed. 3) 402. 1829. Aster lateri- florus (L.) Britton var. horizontalis (Desf.) Farw., Asa Gray Bull. 3:21. 1895. e. Symphyotrichum lateriflorum (L.) Love & Love var. lateriflorum Aster vimineus Lam., Encycl. 1:306. 1783. f. Symphyotrichum lateriflorum (L.) Love & Love var. spatelli- forme (Burgess) Nesom, comb. nov. BASIONYM: Aster spatel- liformis Burgess in Small, Fl. Southeast. U.S. 1225, 1340. 1903. Aster lateriflorus (L.) Britton var. spatelliformis (Burgess) A.G. Jones, Phytologia 55:379. 1984. g- Symphyotrichum lateriflorum (L.) Love & Love var. tenuipes (Wieg.) Nesom, comb. nov. BASIONYM: Aster lateriflorus (L.) Britton var. tenuipes Wieg., Rhodora 30:174. 1928. 286 48. 49 52. 53. 54. 55. 56. PHY TO LOGZ4 volume 77(3):141-297 | September 1994 Aster acadiensis Shinners, Rhodora 46:31. 1944. Symphyotrichum laurentianum (Fernald) Nesom, comb. nov. BA- SIONYM: Aster laurentianus Fernald, Rhodora 16:59. 1914. Brachyac- tts laurentianus (Fernald) Botsch., Not. Syst. Herb. Inst. Bot. Acad. Sci. URSS 16:384. 1954. Aster laurentianus Fernald var. magdalenensis Fernald, Rhodora 16:59. 1914. . Symphyotrichum lentum (E. Greene) Nesom, comb. nov. BASIONYM: Aster lentus E. Greene, Man. Bay Reg. 180. 1894. Aster chilensts Nees var. lentus (E. Greene) Jepson, Man. Fl. Pl. Calif. 1047. 1925. Aster sonomensis E. Greene, Man. Bay Reg. 179. 1894. Aster chilensis Nees var. sonomensis (E. Greene) Jepson, Man. Fl. Pl. Calif. 1047. 1925. . Symphyotrichum leone (Britton) Nesom, comb. nov. BASIONYM: Aster leonis Britton, Mem. Torrey Bot. Club 16:114. 1920. . Symphyotrichum longifolium (Lam.) Nesom, cornb. nov. BASIONYM: Aster longifolius Lam., Encycl. 1:306. 1783. Symphyotrichum lowrieanum (Porter) Nesom, comb. nov. BA- SIONYM: Aster lowrieanus Porter, Bull. Torrey Bot. Club 21:121. 1894. Aster cordifolius L. var. laevigatus Porter, Bull. Torrey Bot. Club 16:67. 1889. Symphyotrichum lucayanum (Britton) Nesom, comb. nov. BA- SIONYM: Aster lucayanus Britton, Bull. N.Y. Bot. Gard. 4:143. 1906. Virgulus lucayanus (Britton) Reveal & Keener, Taxon 30:649. 1981. Symphyotrichum martii (Cabrera) Nesom, comb. nov. BASIONYM: Aster martit Baker in Mart., Fl. Bras. 6(3):23. 1882. Symphyotrichum molle (Rydb.) Nesom, comb. nov. BASIONYM: Aster mollis Rydb., Bull. Torrey Bot. Club 28:22. 1901. Symphyotrichum moranense (Kunth) Nesom, comb. nov. BASIO- NYM: Aster moranensis Kunth, Nov. Gen. & Sp. 4 [folio]:73. 1818. Virgulus moranensis (Kunth) Reveal & Keener, Taxon 30:650. 1981. a. Symphyotrichum moranense (Kunth) Nesom var. moranense Aster lima Lindl. ez DC., Prodr. 5:230. 1836. Virgulus ima (DC.) Reveal & Keener, Taxon 30:650. 1981. Nesom: Review of Aster taxonomy 287 b. Symphyotrichum moranense (Kunth) Nesom var. turneri (S.D. Sundb. & A.G. Jones) Nesom, comb. nov. BASIONYM: Aster moranensis Kunth var. turneri §.D. Sundb. & A.G. Jones, Bull. Torrey Bot. Club 113:176. 1986. 57. Symphyotrichum novae-angliae (L.) Nesom, comb. nov. BASIONYM: Aster novae-angliae L., Sp. Pl. 2:875. 1753. Lasallea novae-angliae (L.) Semple & Brouillet, Amer. J. Bot. 67:1022. 1980. Virgulus novae-angliae (L.) Reveal & Keener, Taxon 30:649. 1981. 58. Symphyotrichum novi-belgii (L.) Nesom, comb. nov. BASIONYM: Aster novt-belgit L., Sp. Pl. 2:877. 1753. a. Symphyotrichum novi-belgii (L.) Nesom var. elodes (Torr. & Gray) Nesom, comb. nov. BASIONYM: Aster elodes Torr. & Gray, Fl. N. Amer. 2:136. 1841. Aster novi-belgit L. var. elodes (Torr. & Gray) A. Gray, Synopt. Fl. 1(2):190. 1884. b. Symphyotrichum novi-belgii (L.) Nesom var. litoreum (A. Gray) Nesom, comb. nov. BASIONYM: Aster novti-belgit L. var. kitoreus A. Gray, Synopt. Fl. 1(2):189. 1884. c. Symphyotrichum novi-belgi: (L.) Nesom var. novi-belgti d. Symphyotrichum novi-belgii (L.) Nesom var. tardiflorum (L.) Nesom, comb. nov. BASIONYM: Aster tardiflorus L., Sp. Pl., (ed. 2). 2:1231. 1763. Aster novi-belgit L. subsp. tardiflorus (L.) A.G. Jones, Phytologia 55:385. 1984. Aster novi-belgit L. var. tardiflorus (L.) A.G. Jones, Phytologia 63:132. 1987. 59. Symphyotrichum oblongifolium (Nutt.) Nesom, comb. nov. BA- SIONYM: Aster oblongifolius Nutt., Gen. N. Amer. Pl. 2:156. 1818. Lasallea oblongifolia (Nutt.) Semple & Brouillet, Amer. J. Bot. 67:1022. 1980. Virgulus oblongifolius (Nutt.) Reveal & Keener, Taxon 30:650. 1981. Aster oblongifolius Nutt. var. angustatus Shinners, Amer. Midl. Nat. 26:418. 1941. Virgulus oblongifolius (Nutt.) Reveal & Keener var. angustatus (Shinners) Reveal & Keener, Taxon 30:650. 1981. Aster oblongtfolius Nutt. var. rigidulum A. Gray, Synopt. Fl. 1(2):179. 1884. 60. Symphyotrichum ontarione (Wieg.) Nesom, comb. nov. BASIONYM: ' Aster ontarionis Wieg., Rhodora 30:179. 1928. (See Semple & Brammall 1982.). 288 PHYTOLOGIA volume 77(3):141-297 September 1994 61. Symphyotrichum oolentangiense (Riddell) Nebans! comb. nov. BA- SIONYM: Aster oolentangiensis Riddell, Synopsis Fl. W. States, West. J. Med. & Phys. Sci. 8:495. 1835. a. Symphyotrichum oolentangiense (Riddell) Nesom var. oolentangiense Aster oolentangiensis Riddell var. laevicaulis (Fernald) A.G. Jones, Bull. Torrey Bot. Club 110:41. 1983. Aster azureus Lindl. in Hook., Comp. Bot. Mag. 1:98. 1835. b. Symphyotrichum oolentangiense (Riddell) Nesom var. poaceum (Burgess) Nesom, comb. nov. BASIONYM: Aster poaceus Burgess in Small, Fl. Southeast. U.S. 1215, 1339. 1903. Aster oolentang- tensis Riddell var. poaceus (Burgess) A.G. Jones, Bull. Torrey Bot. Club 110:41. 1983. Aster vernalis Engelm. ez Burgess in Small, Fl. Southeast. U.S. 1215, 1339. 1903. 62. Symphyotrichum parviceps (Burgess) Nesom, comb. nov. BASIO- - NYM: Aster ericotdes L. var. parviceps Burgess in Britton & Brown, Illus. Fl. 3:379. 1898. Aster parviceps (Burgess) Mack. & Bush, Man. FI. Jackson Co. Missouri 196. 1902. Aster pilosus Willd. subsp. parviceps (Burgess) A.G. Jones, Phytologia 55:381. 1984. 63. Symphyotrichum patens (Aiton) Nesom, comb. nov. BASIONYM: Aster patens Sol. ez Aiton, Hort. Kew. 2:201. 1789. Lasallea patens (Aiton) Semple & Brouillet, Amer. J. Bot. 67:1023. 1980. Virgulus patens (Aiton) Reveal & Keener, Taxon 30:650. 1981. a. Symphyotrichum patens (Aiton) Nesom ‘ar. gracile (Hook.) Nesom, comb. nov. BASIONYM: Aster patens Sol. ez Aiton var. gracilis Hook., Comp. Bot. Mag. 1:97. 1835. Virgulus patens (Aiton) Reveal & Keener var. gracilis (Hook.) Reveal & Keener, Taxon 30:650. 1981. b. Symphyotrichum patens (Aiton) Nesom var. patens c. Symphyotrichum patens (Aiton) Nesom var. patentissimum (DC.) Nesom, comb. nov. BASIONYM: Aster patentissimus Lindl. ez DC., Prodr. 5:232. 1836. Aster patens Sol. ex Aiton var. paten- tisstmus (DC.) Torr. & Gray, N. Amer. Fl. 2:115. 1841. Virgulus patens (Aiton) Reveal & Keener var. patentisstmus (DC.) Reveal & Keener, Taxon 30:650. 1981. 64. Symphyotrichum patagonicum (Cabrera) Nesom, comb. nov. BA- SIONYM: Aster patagonicus Cabrera, Fl. Patag. 7:74. 1971. Nesom: Review of Aster taxonomy 289 65. Symphyotrichum peteroanum (Phil.) Nesom, comb. nov. BASIO- NYM: Aster peteroanus Phil., Anales Univ. Chile 87:406. 1894. 66. Symphyotrichum phlogifolium (Muhl. ez Willd.) Nesom, comb. nov. BASIONYM: Aster phlogifolius Muhl. ez Willd., Sp. Pl. 3:2034. 1803. Virgulus patens (Aiton) Reveal & Keener var. phlogifolius (Muhl. ez Willd.) Reveal & Keener, Taxon 30:650. 1981. 67. Symphyotrichum pilosum (Willd.) Nesom, comb. nov. BASIONYM: Aster pilosus Willd., Sp. Pl. 3:2025. 1803. a. Symphyotrichum pilosum (Willd.) Nesom var. pilosum b. Symphyotrichum pilosum (Willd.) Nesom var. pringlei (A. Gray) Nesom, comb. nov. BASIONYM: Aster ertcoides L. var. pringle:i A. Gray, Synopt. Fl. 1(2):184. 1884. Aster pringlet (A. Gray) Britton in Britton & Brown, JIlus. Fl. 3:379. 1898. Aster ptlosus Willd. var. pringle: (A. Gray) S.F. Blake, Rhodora 32:140. 1930. Aster pilosus Willd. var. demotus S.F. Blake, Rhodora 32:139. 1930. 68. Symphyotrichum porteri (A. Gray) Nesom, comb. nov. BASIONYM: Aster portert A. Gray, Proc. Amer. Acad. Arts 16:99. 1881. Aster ericoides L. var. strictus Porter in Porter & Coulter, U.S. Dept. Interior Misc. Pub. 4:56. 1874. 69. Symphyotrichum potosinum (A. Gray) Nesom, comb. nov. BA- SIONYM: Aster potosinus A. Gray, Proc. Amer. Acad. Arts 15:32. 1880. 70. Symphyotrichum praealtum (Poir.) Nesom, comb. nov. BASIONYM: Aster praealtus Poir., Encycl., Suppl. 1(2):493. 1811. a. Symphyotrichum praealtum (Poir.) Nesom var. angustior (Wieg.) Nesom, comb. nov. BASIONYM: Aster praealtus Poir. var. angus- tior Wieg., Rhodora 35:24. 1933. b. Symphyotrichum praealtum (Poir.) Nesom var. praealtum Aster coerulescens DC., Prodr. 5:235. 1836. Aster praealtus Poir. var. coerulescens (DC.) A.G. Jones, Phytologia 55:383. 1984. Aster praealtus Poir. var. imbricatior Wieg., Rhodora 35:26. 1933. Aster nebraskensis Britton in Britton & Brown, Illus. Fl. 3:375. 1898. Aster praealtus Poir. var. nebraskensis (Britton) Wieg., Rhodora 35:25. 1933. 290 PHYTOLOGIA volume 77(3):141-297 September 1994 c. Symphyotrichum praealtum (Poir.) Nesom var. subasperum (Lindl.) Nesom, comb. nov. BASIONYM: Aster subasper Lindl. in Hook., Comp. Bot. Mag. 1:97. 1835. Aster praealtus Poir. var. subasper (Lindl.) Wieg., Rhodora 35:24. 1933. d. Symphyotrichum praealtum (Poir.) Nesom var. texicola (Wieg.) Nesom, comb. nov. BASIONYM: Aster praealtus Poir. var. tezicola Wieg., Rhodora 35:25. 1933. 71. Symphyotrichum pratense (Rafin.) Nesom, comb. nov. BASIONYM: Aster pratensis Rafin., Fl. Ludov. 67. 1817. Lasaliea sericea ( Vent.) E. Greene var. pratensis (Rafin.) Semple & Brouillet, Ainer. J. Bot. 67:1022. 1980. Virgulus pratensis (Rafin.) Reveal & Keener, Taxon 30:649. 1981. Aster phyllolepis Torr. & Gray, Fl. N. Amer. 2:113. 1841. Aster sericeus Vent. var. microphyllus DC., Prodr. 5:233. 1836. 72. Symphyotrichum prenanthoides (Muhl. ez Willd.) Nesom, comb. nov. BASIONYM: Aster prenanthoides Muhl. ez Willd., Sp. Pl. 3:2046. 1803. 73. Symphyotrichum priceae (Britton) Nesom, comb. nov. BASIONYM: Aster priceae Britton, Man. 960. 1901. Aster pilosus Willd. var. priceae (Britton) Cronq., Rhodora 50:28. 1948. 74. Symphyotrichum puniceum (L.) Love & Love, Taxon 31:359. 1983. BA- SIONYM: Aster puniceus L., Sp. Pl. 2:875. 1753. a. Symphyotrichum puniceum (L.) Love & Love var. calderi (Boivin) Nesom, comb. nov. BASIONYM: Aster cal/dert Boivin, Canad. Field-Nat. 65:14. 1951. Aster puniceus L. var. calderi (Boivin) Lepage, Naturaliste Canad. 79:181. 1952. b. Symphyotrichum puniceum (L.) Love & Love var. puniceum Aster salictfolius Lam., Encycl. 306. 1783. c. Symphyotrichum puniceum (L.) Love & Léve var. scabricaule (Shinners) Nesom, comb. nov. BASIONYM: Aster scabricaulis Shinners, Field & Lab. 21:156. 1953. Aster puniceus L. var. scabri- caults (Shinners) A.G. Jones, Phytologia 55:384. 1984. 75. Symphyotrichum racemosum (Elliott) Nesom, comb. nov. BASIO- NYM: Aster racemosus Elliott, Sketch 2:348. 1823. Aster fragilis Willd., Sp. Pl. 3:2051. 1803. (misapplied, see Gleason & Cronquist 1991.). Nesom: Review of Aster taxonomy 291 76. rp a 78. 79. 80. 81. 82. 83. a. Symphyotrichum racemosum (Elliott) Nesom var. racemosum Aster brachypholis Small, Man. Southeast. Fl. 1389, 1509. 1933. Aster fragilis Willd. var. brachypholis (Small) A.G. Jones, Phy- tologia 55:377. 1984. b. Symphyotrichum racemosum (Elliott) Nesom var. subdumo- sum (Wieg.) Nesom, comb. nov. BASIONYM: Aster vimineus Lam. var. subdumosus Wieg., Rhodora 30:171. 1928. Aster frag- tlis Willd. var. subdumosus (Wieg.) A.G. Jones, Phytologia 55:378. 1984. Symphyotrichum regnellii (Baker) Nesom, comb. nov. BASIONYM: Aster regnellit Baker in Mart., Fl. Brasil. 6(3):21. 1882. (not Erigeron regnellit Sch.-Bip., Linnaea 22:571. 1849. [nom. nud.]). Symphyotrichum retroflexum (DC.) Nesom, comb. nov. BASIONYM: Aster retroflerus Lindl. er DC., Prodr. 5:244. 1836. Aster curtisit Torr. & Gray, Fl. N. Amer. 2:110. 1841. Symphyotrichum sagittifolium (Wedem. ez Willd.) Nesom, comb. nov. BASIONYM: Aster sagittifolius Wedem. ez Willd., Sp. Pl. 3:2035. 1803. Aster cordifolius L. subsp. sagittifolius (Wedem. ez Willd.) A.G. Jones, Brittonia 32:249. 1980. Aster cordifolius L. var. sagittifolius (We- dem. ez Willd.) A.G. Jones, Phytologia 63:131. 1987. Symphyotrichum schaffneri (S.D. Sundb. & A.G. Jones) Nesom, comb. nov. BASIONYM: Aster schaffnert Sch.-Bip. ez §.D. Sundb. & A.G. Jones, Bull. Torrey Bot. Club 113:173. 1986. Symphyotrichum sericeum (Vent.) Nesom, comb. nov. BASIONYM: Aster sericeus Vent., Hort. Cels. t. 33. 1800. Lasallea sericea (Vent.) E. Greene, Leafl. Bot. Observ. Crit. 1:5. 1903. Virgulus sericeus ( Vent.) Reveal & Keener, Taxon 30:649. 1981. Symphyotrichum shortii (Lindl.) Nesom, comb. nov. BASIONYM: Aster shortu Lindl. in Hook., Fl. Bor.-Amer. 2:9. 1834. Symphyotrichum simmondsii (Small) Nesom, comb. nov. BASIO- NYM: Aster stmmondsii Small, Fl. Miam: 190, 200. 1913. Symphyotrichum spathulatum (Lindl.) Nesom, comb. nov. BA- SIONYM: Aster spathulatus Lindl. in Hook., Fl. Bor-Amer. 2:8. 1834. Aster subspathulatus Rydb. [nom. nov.], Mem. New York Bot. Gard. 1:395. 1900. See comments by Cronquist 1994. 292 PHY T OLGA volume 77(3):141-297 September 1994 a. Symphyotrichum spathulatum (Lindl.) Nesom var. fremontii (Torr. & Gray) Nesom, comb. nov. BASIONYM: Aster ascendens Lindl. in Hook. var. fremontit Torr. & Gray, Fl. N. Amer. 2:503. 1841. Aster fremonti (Torr. & Gray) A. Gray, Synopt. Fl. 1(2):191. 1884. Aster occidentalis (Nutt.) Torr. & Gray var. fremontz (Torr. & Gray) A.G. Jones, Phytologia 63:132. 1987. b. Symphyotrichum spathulatum (Lindl.) Nesom var. intermedi- um (A. Gray) Nesom, comb. nov. BASIONYM: Aster occiden- talis (Nutt.) Torr. & Gray var. intermedius A. Gray, Synopt. Fi. 1(2):192. 1884. Aster spathulatus Lindl. zn Hook. var. intermedius (A. Gray) Cronq., Intermountain Fl. 5:294. 1994. c. Symphyotrichum spathulatum (Lindl.) Nesom var. spathulatum Aster delectabilis Hall, Univ. Calif. Pub. Bot. 3:82. 1907. Aster occidentalis (Nutt.) Torr. & Gray var. delectabilis (Hall) Ferris, Madrono 15:128. 1959. Aster fremonti (Torr. & Gray) A. Gray var. parishit A. Gray, Synopt. Fl. 1(2):192. 1884. Aster occidentalis (Nutt.) Torr. & Gray var. parishii (A. Gray) Ferris, Madrono 15:128. 1959. Tripolium occidentale Nutt., Trans. Amer. Philos. Soc., ser. 2, 7:296. 1840. Aster occidentalis (Nutt.) Torr. & Gray, Fl. N. Amer. 2:164. 1841. d. Symphyotrichum spathulatum (Lindl.) Nesom var. yosemi- tanum (A. Gray) Nesom, comb. nov. BASIONYM: Aster ascen- dens Lindl. in Hook. var. yosemitanus A. Gray, Synopt. Fil. 1(2):191. 1884. Aster occidentalis (Nutt.) Torr. & Gray var. yosemitanus (A. Gray) Cronq., Amer. Midl. Nat. 29:467. 1943. Aster paludicola Piper, Contr. U.S. Natl. Her). 16:210. 1913. 84. Symphyotrichum squamatum (Spreng.) Nesom, comb. nov. BA- SIONYM: Conyza squamata Spreng., Syst. Veg., (ed. 16) 3:515. 1826. Aster squamatus (Spreng.) Hieron. in Sod., Bot. Jahrb. Syst. 29:19. 1900. Conyzanthus squamatus (Spreng.) Tamamsch., Fl. U.R.S.S. 25:186. 1959. Aster subtropicos Morong, Ann. N.Y. Acad. Sci. 7:139. 1893. Aster subulatus Michx. var. sandwicensis (A. Gray) A.G. Jones, Brit- tonia 36:465. 1984. Aster divaricatus var. sandwicensis A. Gray, Proc. Amer. Acad. Arts 7:173. 1867. Tripolium conspicuum Lindley ez DC., Prodr. 5:254. 1836. Baccharis asteroides Colla, Mem. Reale Accad. Sci. Torino 38:14. 1835. Aster asteroides (Colla) Rusby, Mem. Torrey Bot. Club 4:213. 1893. Nesom: Review of Aster taxonomy 293 85. 86. 87. 88. 89. 90. 91. 92. Symphyotrichum subgeminatum (Fernald) Nesom, comb. nov. BA- SIONYM: “Aster foliaceus Lindl. ez DC. var. subgeminatus Fernald, Rhodora 17:16. 1915. Aster subgeminatus (Fernald) Boivin, Natural- iste Canad. 75:211. 1948. [E. ciliolata x E. tardiflora?}. Symphyotrichum subspicatum (Nees) Nesom, comb. nov. BASIO- NYM: Aster subspicatus Nees, Gen. Sp. Aster. 74. 1832. Aster douglasi Lindl. in Hook., Fl. Bor.-Amer. 2:11. 1834. a. Symphyotrichum subspicatum (Nees) Nesom var. subspicatum b. Symphyotrichum subspicatum (Nees) Nesom var. grayi (Suksd.) Nesom, comb. nov. BASIONYM: Aster gray: Suksd., Werwenda 1:41. 1927. Aster subspicatus Nees var. grayt (Suksd.) Cronq., Vasc. Pl. Pac. Northw. 5:97. 1955. Symphyotrichum subulatum (Michx.) Nesom, comb. nov. BASIO- NYM: Aster subulatus Michx., Fl. Bor.-Amer. 2:111. 1803. Mesoligus subulatus (Michx.) Rafin., Fl. Tellur. 2:44. 1836 [1837]. Symphyotrichum tenuifolium (L.) Nesom, comb. nov. BASIONYM: Aster tenutfolius L., Sp. Pl. 2:873. 1753. Symphyotrichum tradescantii (L.) Nesom, comb. nov. BASIONYM: Aster tradescantiu L., Sp. Pl. 2:876. 1753. Aster vimineus Lam. var. sazatilts Fernald, Rhodors 1:188. 1899. Aster sazatilis (Fernald) Blanch. (comb. illeg.|, Amer. J. Bot. 7:27. 1904. (not Aster saratilis [Remy] O. Kuntze 1891.). Symphyotrichum trilineatum (Sch.-Bip. ez Klatt) Nesom, comb. nov. Aster trilineatus Sch.-Bip. ez Klatt, Leopoldina 20:91. 1844. Aster bimater Standl. & Steyerm., Field Mus. Publ., Bot. 23:141. 1944. Virgulus bimater (Standl. & Steyerm.) Reveal & Keener, Taxon 30:650. 1981. Symphyotrichum turbinellum (Lindl.) Nesom, comb. nov. BA- SIONYM: Aster turbinellus Lindl in Hook., Comp. Bot. Mag. 1:98. 1835. Symphyotrichum undulatum (L.) Nesom, comb. nov. BASIONYM: Aster undulatus L., Sp. Pl. 2:875. 1753. Aster undulatus L. var. asperulus Wood, Amer. Bot. Fl. 162. 1870. Aster undulatus L. var. loriformis Burgess in Britton & Brown, IIlus. Fl. 3:365. 1898. 294 PHYTOLG GIA volume 77(3):141-297 September 1994 93. Symphyotrichum urophyllum (DC.) Nesom, comb. nov. BASIONYM: 94. 95. Symphyotrichum walteri (Alexander) Nesom, comb. nov. BASIONYM: Aster urophyllus Lindl. er DC., Prodr. 5:233. 1836. Aster sagtttifohus Wedem. ez Willd. var. urophyllus (DC.) Burgess in Britton & Brown, Illus. Fl. 3:365. 1898. Symphyotrichum vahlii (Gaud.) Nesom, comb. nov. BASIONYM: Erigeron vahlii Gaud., Ann. Sci. Nat. (Paris) 5:104. 1825. Aster vahlu (Gaud.) Hook. & Arn., Companion Bot. Mag. 2:49. 1836. a.. Symphyotrichum vahlit (Gaud.) Nesom var. vahli b. Symphyotrichum vahlii (Gaud.) Nesom var. tenuifolium (Phil.) Nesom, comb. nov. BASIONYM: Tripolium tenu:folium Phil., Ana- les Univ. Chile 87:404. 1894. Aster vahlit (Gaud.) Hook. & Arn. var. tenutfolius (Phil.) Cabrera, Revista Chil. Hist. Nat. 40:227. 1936. Aster walter: Alexander in Small, Man. Southeast. Fl. 1382, 1509. 1933. Lasallea walter: (Alexander) Semple & Brouillet, Amer. J. Bot. 67:1023. 1980. Virgulus walter: (Alexander) Reveal & Keener, Taxon 30:650. 1981. 96. Symphyotrichum welshii (Cronq.) Nesom, comb. nov. BASIONYM: 97. Aster welshit Crong., Intermountain Fl. 5:291. 1994. Symphyotrichum yukonense (Cronq.) Nesom, comb. nov. BASIO- NYM: Aster yukonensis Crong., Madrono 8:98. 1945. Virgulus yuko- nensis (Cronq.) Reveal & Keener, Taxon 30:650. 1981. Hybrids in Symphyotrichum: 1. Symphyotrichum x amethystinum (Nutt.) Nesom, comb. nov. BA- SIONYM: Aster amethystinus Nutt. [pro sp.|, Trans. Amer. Philos. Soc., ser. 2, 7:294. 1841. Lasallea x amethystana (Nutt.) Semple & Brouillet, Amer. J. Bot. 67:1022. 1980. Virgulus x amethystanus (Nutt.) Reveal & Keener, Taxon 30:649. 1981. [S. ericoides x S. novae-angliae]. 2. Symphyotrichum x batesii (Rydb.) Nesom, comb. nov. BASIONYM: Aster batesi Rydb. [pro sp.|, Brittonia 1:102. 1931. [S. ericotdes x S. oblongtfolium|. 3. Symphyotrichum x columbianum (Piper) Nesom, comb. nov. BA- SIONYM: Aster columbianus Piper [pro sp.], Contr. U.S. Natl. Herb. Nesom: Review of Aster taxonomy 295 16:210. 1913. Aster multiflorus Sol. ex Aiton var. columbianus (Piper) S.F. Blake, Rhodora 30:227. 1928. Virgulus x columbianus (Piper) Re- veal & Keener, Taxon 30:649. 1981. [5. campestre x S. ertcoides var. pansum|. 4. Symphyotrichum x finkii (Rydb.) Nesom, comb. nov. BASIONYM: Aster finkit Rydb. [pro sp.|, Brittonia 1:102. 1931. [S. cordifolium x S. shortiz]. 5. Symphyotrichum x gravesii (Burgess) Nesom, com). nov. BASIONYM: Aster gravest Burgess in Britton by sp.|, Man. 961. 1901. [S. dumosum x S. laeve). Symphyotrichum x longulum (Sheldon) Nesom, comb. nov. BA- SIONYM: Aster longulus Sheldon [pro sp.|, Minnesota Bot. Stud. 1:18. 1894. [S. boreale x S. puniceum]. 7. Symphyotrichum x salignum (Willd.) Nesom, comb. nov. BASIONYM: Aster salignus Willd. [pro sp.], Sp. Pl. 3:2040. 1803. [S. lanceolatum x S. novi-belgza}. 8. Symphyotrichum x schistosum (Steele) Nesom, comb. nov. BA- SIONYM: Aster schistosus Steele [pro sp.|, Contr. U.S. Natl. Herb. 13:373. 1911. [S. cordifolium x S. laeve]. 9. Symphyotrichum x versicolor (Willd.) Nesom, comb. nov. BASIONYM: Aster versicolor Willd. [pro sp.], Sp. Pl. 3:2045. 1803. [S. laeve x S. novt-belgii}. 10. Symphyotrichum x woldenii (Rydb.) Nesom, comb. nov. BASIONYM: Aster woldenit Rydb. [pro sp.|, Brittonia 1:103. 1931. [S. praealium x S. laeve}. Unknown and excluded taxa: Aster ezilis Elliott, Sketch Bot. S. Carolina 344. 1823. This taxon has been associated with Symphyotrichum ( As- ter) subulatum, but as noted by Shinners (1953) and Sundberg (1986), the type specimen apparently is not extant. Further, it was collected in western Georgia, outside of the range of A. subulatus, and it is likely that it represents some species outside of sect. Ozytripolium. 296 PHYTOLOGIA volume 77(3):141-297 September 1994 Aster sp.-group Exiles Rydb., Fl. Pratries & Plains 803. 1932. Aster sect. Exiles (Rydb.) A.G. Jones, Brittonia 32:233. 1980. Type: Aster ezilis Elliott. Venatris Rafin., Fl. Tellur. 2:47. 1836. [1837]. Lectotype (designated here): Venatris falcata Rafin., FI. Tellur. 2:47. 1836. [1837]. Rafinesque cited various species as “types” of this Aster segregate, but Venatris falcata was noted by him as the “best type of the G.” The latter is based on a collection with the following citation: “East Kentucky, falls of Cumberland, pedal.” The plant was described as glabrous, with erect, sessile, falcate, linear-lanceolate, 1-nerved, and subentire leaves, bearing 3-5 heads with purple rays, and it appears likely to be a species of Symphyotrichum. Venatris falcata is regarded here as a new species first described by Rafinesque, as there is no indication that the name was based on Aster falcatus Lindl., nor does this species occur in eastern Kentucky. The identity of Venatris falcata has not been established. XIII. TONESTUS A. Nelson, Bot. Gaz. (Crawfordsville) 37:262. 1904. Type: Tonestus lyallii (A. Gray) A. Nelson. 1. Tonestus aberrans (A. Nelson) Nesom & Morgan, Phytologia 68:178. 1990. BASIONYM: Macronema aberrans A. Nelson, Bot. Gaz. (Craw- fordsville) 53:226. 1912. Haplopappus aberrans (A. Nelson) H.M. Hall, Carnegie Inst. Washington Publ. 389:185. 1928. 2. Tonestus alpinus (Anderson & Goodrich) Nesom & Morgan, Phytologia 68:178. 1990. BASIONYM: Haplopappus alpinus Anderson & Goodrich, Great Basin Nat. 40:73. 1980. 3. Tonestus ezimius (H.M. Hall) Nelson & Macbr., Bot. Gaz. (Crawfordsville) 65:70. 1918. BASIONYM: Haplopappus ezimius H.M. Hall, Univ. Calif. Pub. Bot. 6:170. 1915. 4. Tonestus graniticus (Tiehm & Schulz) Nesom & Morgan, Phytologia 68:178. 1990. BASIONYM: Haplopappus graniticus Tiehm & Schulz, Brittonia 37:165. 1985. 5. Tonestus king (D.C. Eaton) Nesom, Phytologia 71:125. 1991. BA- SIONYM: Aster kingit D.C. Eaton, Bot. Fortieth Parallel 5:141. 1871. Machaeranthera kingit (D.C. Eaton) Cronq. & Keck, Brittonia 9:239. 1957. Nesom: Review of Aster taxonomy 297 a. Tonestus kingii (D.C. Eaton) Nesom var. barnebyana (Welsh & Goodrich) Nesom, Phytologia 71:125. 1991. BASIONYM: Machaer- anthera kingit (D.C. Eaton) Cronq. & Keck var. barnebyana Welsh & Goodrich, Brittonia 33:299. 1981. Aster kingizt D.C. Eaton var. barnebyana (Welsh & Goodrich) Welsh, Great Basin Nat. 43:221. 1983. b. Tonestus kingit (D.C. Eaton) Nesom var. kingzt 6. Tonestus lyallii (A. Gray) A. Nelson, Bot. Gaz. (Crawfordsville) 37:262. 1904. BASIONYM: Haplopappus lyallii A. Gray, Proc. Acad. Nat. Sci. Philad. 1863:64. 1864. Stenotus lyallii (A. Gray) J.T. Howell, Fl. N. W. Amer. 300. 1900. 7. Tonestus peirsonit (Keck) Nesom & Morgan, Phytologia 68:178. 1990. BASIONYM: dHaplopappus ezimius H.M. Hall subsp. petrsoni Keck, Madrono 5:169. 1940. 8. Tonestus pygmaeus (Torr. & Gray) A. Nelson, Bot. Gaz. (Crawfordsville) 37:262. 1904. BASIONYM: Stenotus pygmaeus Torr. & Gray, Fl. N. Amer. 2:237. 1842. Haplopappus pygmaeus (Torr. & Gray) A. Gray, Amer. J. Sci., ser. 2, 33:238. 1862. Phytologia (September 1994) 77(3):298-307. HYBRIDIZATION IN THE TRIBE ASTEREAE (ASTERACEAE) Guy L. Nesom Department of Botany, University of Texas, Austin, Texas 78713 U.S.A. ABSTRACT Interspecific hybrids occur naturally in the Astereae within a num- ber of genera, but hybrids also occur between species of distinct and generally accepted but closely related genera. Intergeneric hybrids also have been artificially synthesized between species of more distantly re- lated genera (of different but closely related subtribes). KEY WORDS: hybrids, Astereae, Asteraceae In the course of a survey and classification of the tribe Astereae (Nesom 1994b), I have assembled observations regarding hybridization that have a general bearing on the interpretation of taxonomic patterns within the tribe. This paper summarizes the findings. INTERSPECIFIC HYBRIDS WITHIN A GENUS Spontaneous, infrageneric hybrids are reported to occur between species within numerous genera of Astereae; they appear to be commonly formed in several large, homobasic genera where species have overlapping geographic ranges, suggesting that isolating mechanisms may be external (primarily geo- graphic) rather than internal. This is emphasized by studies of genera where natural hybrids are relatively rare or unknown but where artificial interspecific hybrids are readily synthesized (e.g., Tetramoloptum, Lowrey 1986). The effect of internal isolating mechanisms is more evident in genera where chromosome numbers are reduced (less than z=8) and different among the species (e.g., in Machaeranthera sensu lato — Jackson 1993; Jackson et al. 1993; Astranthium ~ DeJong 1965), this attributable at least in part to structural incompatibility of the chromosomes. Fertile hybrids between widely heterobasic species within the North American Symphyotrichum (a segregate from Aster; Nesom 1994c), however, make such a generalization difficult (see below). 298 Nesom: Hybridization in Astereae 299 Natural hybrids are particularly well-known in Townsendia (Beaman 1957) and in Solidago and Symphyotrichum (e.g., see comments on both genera in Gleason & Cronquist ed. 1, 1963 and ed. 2, 1991; representation of inter- sectional and intersubgeneric hybridization in Nesom 1994c; Symphyotrichum formerly considered a large group of North American Aster). Semple & Bram- mall (1982), however, noted that the extent of interspecific hybridization in Symphyotrichum is perhaps not as wide as generally supposed, much of the confusing variation within species instead attributable tc phenotypic plastic- ity. Intersectional hybrids occur in Solidago (see Nesom 1993) as well as in Symphyotrichum (see below). Hybrids in various combinations of species also are known within Oligoneuron, which has sometimes been treated within Sol- idago, but the only putative hybrid between Solidago and Oligoneuron is the taxon x Solidaster (see Nesom 1993 and comments below), formed and evi- dently perpetuated from the results of a single, spontaneous crossing event. Fertile, naturally occurring hybrids occur within Symphyotrichum between homobasic parents (diploid and polyploid) as well as between species of dif- ferent base chromosome number and highly modified karyotypes. Sundberg (1986) discovered a population system of fertile plants from Oaxaca, México with a chromosome number of n=13, apparently the result of a cross between an z=5 parent (sect. Ozytripolium) and an z=8 parent (sect. Dumosi). In a series of papers, Jones (1977), Dean & Chambers (1983), Allen et al. (1983), and Allen (1984, 1985, 1986) have documented the hybrid origin of a fertile, well-known species S. (Aster) ascendens (Lindl.) Nesom, n=13 and polyploid levels) between heterobasic parents of different subgenera (z=8 - subg. Sym- phyotrichum and z=5 — subg. Virgulus and the reticulate nature of phyletic relationships in this species complex. Another accepted species (5S. defoltatum (Parish) Nesom = Aster bernardinus Hall; n=18) originated as a backcross between S. ascendens (n=13) and S. [Aster] falcatum (Lindl.) Nesom (n=5), one of the parents of S. ascendens. Both of these alloploid species backcross in various combinations to both parents as well as other taxa (extra-parental, in both subgenera) of this species complex. Semple (1985) has divided the plants of this complex among three genera: the virguloid and symphyotrichoid par- ents each representing a different genus and those with a genetic amalgam (F,’s and backcrosses) representing a third. Such a taxonomic approach is unique in the Astereae and, in my opinion, overemphasizes the degree of evolutionary divergence of the parents. One artificially produced hybrid within Symphyotrichum (reported as Aster, Avers 1957) that was originally regarded as “wide” has been reinterpreted as a cross between two related species with the same base chromosome number (z=8): S. cordifolium (L.) Nesom (n=8) and S. turbinellum (Lindl.) Nesom (n=48). Within both Symphyotrichum subg. Symphyotrichum (sect. Dumost) and the genus Eurybia (= Aster subg. Biotia), some species apparently are of hybrid origin (Semple & Brammall 1982; Lamboy et al. 1991) and the inter- 300 PHYTOLOQGIA volume 77(3):298-307 September 1994 pretation of species relationships is correspondingly complex. The occurrence of an intersectional hybrid between sect. Eurybia and sect Calliastrum (Uttal 1962; Nesom 1994b), the parental species strongly divergent in morphology, is perhaps facilitated by the high ploidy level of both parents. Another remarkable and well-documented area of natural hybridization in the Astereae is in the genus Chrysopsis (Semple & Chinnappa 1980a, 1980b; Semple 1981), which has a base chromosome number of z=5. One of the species, C. gossypina Ell., is an alloploid (n=9) originating as a hybrid between parents with n=5 and n=4. Naturally occurring n=7 hybrids exist between C. gossypina and two of the n=5 species (one of the hybrids a backcross), and an artificial 2n=13 hybrid has been constructed between C. gossypina and one of the z=4 species. The z=9 alloploids also have been artificially synthesized. In the large genus Erigeron, there are relatively few putative natural hy- brids, perhaps because of the restricted (non-overlapping) geographic distribu- tions of many of the species, and there are no known hybrids between species of different sections. Within Erigeron sect. Olygotrichium, however, agamic polyploid complexes involving hybrids between E. divergens Torr. & Gray and its close relatives are common. Widespread interspecific hybridization in Bac- charis (Hellwig 1990), apparently strictly infra-sectional, is responsible for at least a part of the taxonomically confusing variation found in that genus. A sample of other Astereaean genera where interspecific hybrids are reported between relatively closely related species are Celmisia (Allan 1961), Felicia (Grau 1973), Oclemena (Pike 1970; see summary in Nesom 1994c), Boltonia (Anderson 1987), Xylorhiza (T. Watson pers. comm.), and Machaeranthera. A naturally formed hybrid has been reported between homobasic species (z=9) of the Australian genera Pleurophyllum and Damnamenia, but the species involved are closely related and probably are best considered congeneric (Drury 1968; Given 1973). Natural hybrids occur between Galatella angustis- sima (Tausch.) Novopokr. and Crinitaria villosa (L.) Grossh. (Tamamschyan 1959), but the inter-relationships of the subgroups within these two closely related genera are poorly understood, as noted by Tamamschyan. Similarly, an artificial “intergeneric” hybrid between Haplopappus and Machaeranthera (Jackson 1993) is reinterpreted as a cross between two species of Machaer- anthera. Natural hybrids reported between taxa of Chrysothamnus and Eri- camerta have been reinterpreted as crosses within the latter genus (Nesom & Baird 1993). A recurrent hybrid combination between two species of Eri- camerta strongly divergent in habit and capitulescence has been documented by Urbatsch & Wussow (1979), who placed them in the same section of the genus. INTERGENERIC HYBRIDS Among genera of Astereae reasonably accepted as distinct (Nesom 1994b), Nesom: Hybridization in Astereae 301 there are reports (documented in varying degrees) of naturally occurring hy- brids between the following: Aster ageratoides Turcz. (2n=36) x Kalimeris incisa (Fisch.) DC. (2n=72); homobasic, z=9, the hybrids fertile (Inoue 1970; Tara 1972, 1979; Gu 1987 and in press); Heteropappus hispidus (Thunb.) Less. (2n=36) x Kalimeris incisa (2n=72); homobasic, z=9, the hybrids fertile (Huziwara 1950; Inoue 1955; Tara 1973); Polyarrhena reflera (L.) Cass. x Zyrphelis tazifolia (L.) Cass.; homobasic, z=9, the hybrids of unknown fertility (see Nesom 1994a) and needing confirmation of their status; Isocoma veneta (Kunth) E. Greene x Xanthocephalum humile Benth.; ho- mobasic, z=6, the hybrids vegetatively robust but largely sterile (Lane & Hartman 1991); Erigeron [subg. Trimorpha] acris L. x Conyza canadensis (L.) Crongq.; ho- mobasic, z=9, the hybrids recurring but rare and apparently weak and sterile (Stace 1975). Four instances of putative natural hybridization have been reported be- tween species of Olearia and Celmisia (summarized by Clarkson 1988). Among these, at least three of the Olearia parents have been piants of the shrubby species O. arborescens (Forst. f.) Ckn. & Laing; the Celmista parents are species representing at least three subgenera (sensu Given 1969) and range from woody subshrubs to herbs. The hybrids studied in detail by Clarkson (O. arborescens x C. gracilenta J.D. Hook.) are relatively rare and almost completely sterile. I recently suggested that the parents of the spontaneously formed and fer- tile (but apparently only once-formed) intergeneric hybrid x Solidaster might be Oligoneuron album (Nutt.) Nesom and a species of Euthamia (Nesom 1993). The hybrid is maintained in the florist trade (generally by cuttings and divi- sions), and after being able to observe living material, where the shape of the capitulescence in at least some plants may be more asymmetrical than in the herbarium material I have studied, it appears that Solidago canadensis L. (rather than Euthamia) may be a reasonable parental candidate, as sug- gested previously by other botanists (see summary in Nesom 1993). In either case, each parent of Solidaster has a base chromosome number of z=9, and they are relatively closely related within the Solidagininae. At least the orig- inal plant of Solidaster produced fertile achenes; the “F2” progeny also were fertile, although whether they were backcrosses or true F.’s is not clear. 302 PHYTOLQGIA volume 77(3):298-307 September 1994 Intergeneric hybrids have been artificially synthesized between the follow- ing species of different but closely related Astereaean genera (within a sub- tribe): Grindelia papposa Nesom & Suh (= Prionopsis ciliata [Nutt.] Nutt.) x Hap- lopappus annuus Rydb.; homobasic, z=6 (Jackson 1966) (Machaeran- therinae); H. annuus is a member of the “phyllocephalus group,” ac- cepted as a generic-level group of the Machaerantherinae (Nesom 1994b); both Grindelia and the “phyllocephalus group” are members of the “Xanthocephalum Willd. group.” Isocoma veneta (Kunth) E. Greene x Haplopappus aureus A. Gray; homoba- sic, z=6 (Jackson 1966) (Machaerantherinae); H. aureus is a member of the “phyllocephalus group”; Jsocoma and the “phyllocephalus group” are members of the “Xanthocephalum group.” Tracyina rostrata S.F. Blake x Rigiopappus leptocladus A. Gray; homobasic, z=9 (Ornduff & Bohm 1975) (Feliciinae). Intergeneric hybrids have been artificially synthesized between species of North American Astereae apparently more widely separated in relationship: Almutaster (Aster) pauctflorus (c=9) x Machaeranthera arida (Kunth) A.G. Jones (z=5) (Stucky 1978) (Asterinae x Machaerantherinae); Almutaster (Aster) pauciflorus (r=9) x Machaeranthera parviflora A. Gray (z=5) (Stucky 1978) (Asterinae x Machaerantherinae); Symphyotrichum (Aster) tenutfolium (z=5) x Machaeranthera riparia (Kunth) A.G. Jones (z=5) (Jackson 1992a) (Asterinae x Machaerantherinae); Haplopappus (“phyllocephalus group”) aureus A. Gray (x=6) x Machaeran- thera arenaria (Benth.) Shinners (z=4) (Jackson 1985) (Machaerantheri- nae); Haplopappus (“phyllocephalus group”) annuus (z=6) x Machaeranthera havar- dit (Waterf.) Shinners (z=4) (Jackson 1966) (Machaerantherinae). The eight crosses above, with the resultant hybrids weak and infertile, ap- pear to be the widest such documented in the tribe. They represent, however, only a fraction of the wide, artificial crosses that might prove successful but which have not been attempted. The hybrids appear to confirm initial hy- potheses (which led to the experiments) that evolutionary divergence among the species involved has not completely effaced their genomic similarities. In contrast to these artificial crosses, natural intergeneric hybrids in the Astereae have been reported only between species of genera that are clearly Nesom: Hybridization in Astereae 303 closely related. In Powell’s view (1985, p. 56), “any natural ’intergeneric’ hybridization, where at least partial fertility of the hybrids can be estab- lished, should be strongly considered as evidence that the taxa involved are congeneric.” Some natural hybrids in the Astereae are sterile (following the general pattern described by Powell), but those produced in crosses involv- ing Aster, Kalimerts, and Heteropappus show varying degrees of fertility, and at least the immediate descendants of the original Solidaster produced fertile achenes. In the instances of natural intergeneric hybridization summarized here, the parental species may have been considered congeneric in earlier tax- onomic concepts, but there is a consensus in more modern treatments for their recognition as members of distinct genera. There is no strong indication that Astereaean intergeneric hybrids, with caveats above regarding Pleurophyllum x Damnamenia and Galatella x Crinitaria, should be interpreted as evidence for a broadening (or re-broadening) of generic concepts to include both parents. ACKNOWLEDGMENTS I thank Verne Grant, Ray Jackson, Tim Lowrey, Billie Turner, and Tom Watson for their comments on the manuscript and John Beaman for help in locating literature. Where not cited in the discussion above, authorities for taxa can be found in Nesom 1994b and 1994c. LITERATURE CITED Allan, H.H. 1961. Flora of New Zealand. Hasselberg, Govt. Printer, Welling- ton, New Zealand. Allen, G.A. 1984. Morphological and cytological variation in the western North American Aster occidentalis complex (Asteraceae). Syst. Bot. 9:175-191. . 1985. The hybrid origin of Aster ascendens (Asteraceae). Amer. J. Bot. 72:268-277. . 1986. Amphidiploid origin of two endemic races of Aster (Aster- aceae) in southern California. Amer. J. Bot. 73:330-335. Allen, G.A., M.L. Dean, & K.L. Chambers. 1983. Hybridization studies in the Aster occidentalis (Asteraceae) polyploid complex of western North America. Brittonia 35:353-361. 304 PHY TOL@GHA volume 77(3):298-307 | September 1994 Anderson, L.C. 1987. Boltonia apalachicolensis (Asteraceae): a new species from Florida. Syst. Bot. 12:133-138. Avers, C. 1957. Fertile hybrids derived from a wide species cross in Aster. Evolution 11:482-486. Beaman, J.H. 1957. The systematics and evolution of Townsendia (Com- positae). Contr. Gray Herb. 183:1-151. Clarkson, B.D. 1988. A natural intergeneric hybrid, Celmisia gracilenta x Olearia arborescens (Compositae) from Mt. Tarawera, New Zealand. New Zealand J. Bot. 26:325-331. Dean, M.L. & K.L. Chambers. 1983. Chromosome numbers and evolution- ary patterns in the Aster occidentalis (Asteraceae) polyploid complex of western North America. Brittonia 35:189-196. De Jong, D.C.D. 1965. A systematic study of the genus Astranthium (Com- positae, Astereae). Publ. Mus., Michigan State Univ., Biol. Ser. 2(9): 433-528. Drury, D.G. 1968. A clarification of the generic limits of Olearia and Pleu- rophyllum (Astereae - Compositae). New Zealand J. Bot. 6:459-466. Given, D.R. 1969. A synopsis of infrageneric categories in Celmisia (Astereae - Compositae). New Zealand J. Bot. 11:785-796. 1973. Damnamenia gen. nov. A new subantarctic genus allied to Celmisia Cass. (Astereae - Compositae). New Zealand J. Bot. 11:785- 796. Gleason, H.A. & A. Cronquist. 1963. Manual of Vascular Plants of North- eastern United States and Adjacent Canada. Van Nostrand Co., Prince- ton, New Jersey. [ed. 2, 1991, New York Botanical Garden, Bronx, New York]. Grau, J. 1973. Revision der Gattung Felicia (Asteraceae). Mitt. Bot. Staatssamml. Minchen 9:195-705. Gu, H.-y. 1987. A biosystematic study of the genus Kalimeris. Ph.D. disser- tation, Washington Univ., St. Louis, Missouri. . In press. Systematics of Kalimeris (Astereae, Asteraceae). Ann. Missouri Bot. Gard. Hellwig, F.H. 1990. Die Gattung Baccharis L (Compositae - Astereae) in Chile. Mit. Bot. Staatssamml. Miinchen 29:1-456. Nesom: Hybridization in Astereae 305 Huziwara, Y. 1950. Heterokalimeris maruyamae Kitamura. A new inter- generic hybrid of Kalimeris and Heteropappus. Jap. J. Genet. 25:25-26. Inoue, S. 1955. Cytological studies on the natural hybrid arose from the genus Kalimerts and Heteropappus. Jap. J. Genet. 30:169. . 1970. Cytological studies on the intergeneric natural hybrid be- tween Aster and Kalimeris from Kyushu. (1). Chromosome numbers and geographical distribution. Mem. Fac. General Ed., Kumamotu Univ. (Ser. Nat. Sci.) 5:47-52. Jackson, R.C. 1966. Some intersectional hybrids and reiationships in Hap- lopappus. Univ. Kansas Sci. Bull. 46:475-485. 1985. Mitotic instability in Haplopappus: structural and genic causes. Amer. J. Bot. 72:1452-1457. 1992a. Intergeneric hybridization: Mach aeranthera x Aster. Proc. Southwestern & Rocky Mt. Sect. AAAS 7:20. [abstract]. . 1992b. Evolution of and in Haplopappus gracilis: a synopsis. PI. Genet. News Letter 9(1):2-4. . 1993. Intergeneric hybridization: Haplopappus arenarius x Machaer- anthera tagetina. New Mexico J. Sci. 33:20. [abstract]. Jackson, R.C., C.F. Crane, J.S. Johnston, J.R. Ellison, & H.J. Price. 1993. Aneuploidy, structural chromosome changes, and DNA amounts in the annual taxa of the Haplopappus spinulosus complex. Chromosome Res. 1:53-61. Jones, A.G. 1977. New data on chromosome numbers in Aster section Het- erophylli (Asteraceae) and their phylogenetic implications. Syst. Bot. 2:334-347. Lamboy, W.F., D.L. Nickrent, & A.G. Jones. 1991. Isozyme evidence and phenetic relationships among species in Aster section Biotia (Aster- aceae). Rhodora 93:205-225. Lane, M.A. & R.L. Hartman. 1991. A natural intergeneric hybrid in the z=6 group of the Astereae (Asteraceae). Sida 14:321-329. Lowrey, T.K. 1986. A biosystematic revision of Hawaiian Tetramoloptum (Compositae - Astereae). Allertonia 4:204-264. Nesom, G.L. 1993. Taxonomic infrastructure of Solidago and Oligoneuron (Asteraceae: Astereae) and observations on their phylogenetic position. Phytologia 75:1-44. 306 PHYTOLOGIA volume 77(3):298-307 September 1994 . 1994a. Repartition of Mairia (Asteraceae: Astereae). Phytologia 76:85-95. . 1994b. Subtribal classification of the Astereae (Asteraceae). Phy- tologia 76:193-274. . 1994c. Review of the taxonomy of Aster sensu lato (Asteraceae: Astereae), emphasizing the New World species. Phytologia 77:140-297. Nesom, G.L. & G.I. Baird. 1993. Completion of Ericameria (Asteraceae: Astereae), diminution of Chrysothamnus. Phytologia 75:74-93. Ornduff, R. & B.A. Bohm. 1976. Relationships of Tracyina and Bie te Madrono 23:53-55. Pike, R.B. 1970. Evidence for the hybrid status of Aster blake: (Porter) House. Rhodora 72:401-436. Powell, A.M. 1985. Crossing data as generic criteria in the Asteraceae. Taxon 34:55-60. Semple, J.C. 1981. A revision of the goldenaster genus Chrysopsis (Nutt.) Ell. nom. cons. (Compositae - Astereae). Rhodora 83:323-384. 1985. New names and combinations in Compositae, tribe Astereae. Phytologia 58:429-431. Semple, J.C. & R.A. Brammall. 1982. Wild Aster lanceolatus x lateriflorus hybrids in Ontario and comments on the origin of A. ontarionis (Com- positae - Astereae). Canad. J. Bot. 60:1895-1906. Semple, J.C. & C.C. Chinnappa. 1980. Karyotype evolution and chromo- some numbers in Chrysopsis (Nutt.) Ell. sensu Semple (Compositae - Astereae). Canad. J. Bot. 58:164-171. . 1980. Phylogenetic implications of meiosis in wild and cultivated interspecific hybrids in Chrysopsis (Compositae - Astereae): C. godfreyi (n=5) x gossypina ssp. cruiseana (n=9) and C. godfreyi (n=5) x lineartfolia (n=5). Canad. J. Bot. 58:172-181. Stace, C.A. (ed.) 1975. Hybridization and the flora of the British Isles. Academic Press, London, Great Britain. Stucky, J. 1978. Hybridization between Aster and Machaeranthera and its taxonomic significance. Amer. J. Bot. 65:125-133. a Nesom: Hybridization in Astereae 307 Sundberg, S.D. 1986. The systematics of Aster subg. Ozytripohium (Com- positae) and historically allied species. Ph.D. dissertation, University of Texas, Austin, Texas. Tamamschyan, S.G. 1959. Asteraceae: Astereae. Fl. URSS (ed. V.L. Ko- marov) 25:24-290. [English translation, 1990: Bishen Singh Mahendra Pal Singh and Koelz Scientific Books]. Tara, M. 1972. Cytogenetic studies on natural intergeneric hybridization in Aster alliances I. Aster ageratoides subsp. ovatus (2n=36) x Kalimeris incisa (2n=72). Bot. Mag. Tokyo 85:219-240. 1973. Cytogenetic studies on natural intergeneric hybridization in Aster alliances II. Heteropappus hispidus (2n=36) x Kalrneris incisa (2n=72). J. Sci. Hiroshima Univ. Ser. B, Div. 2, Bot. 14:107-140. . 1979. Cytogenetic studies on natural intergeneric hybridization in Aster alliances VII. A new backcross hybrid between Aster ageratotdes subsp. ovatus and Kalimeris incisa. Bot. Mag. Tokyo 92:151-156. Urbatsch, L.E. & J.R. Wussow. 1979. The taxonomic affinities of Haplopap- pus lineartfolius (Asteraceae - Astereae). Brittonia 31:265-275. Uttal, L.J. 1962. Synthesis of Aster herveyt. Rhodora 64:113-117. NOW AVAILABLE, PHYTOLOGIA MEMOIRS, Volume 9 THE UNIVERSITY OF TEXAS HERBARIA TYPE REGISTER CAROL A. TODZIA 1994, 8 1/4 x 10 3/4 in., 288 pp., $17.95, ISBN 0-9642085-0-4. A comprehensive listing of the type specimens found in the University of Texas at Austin Herbaria (LL, TEX). Each specimen fully documented with taxonomic, locality, and publication information. An invaluable reference for anyone requiring information on type specimens from the United States and Latin America (where the majority of the specimens originated). 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