Chromosome Numbers in Compositae, XV: Liabeae
1985; Missouri Botanical Garden; Volume: 72; Issue: 3 Linguagem: Inglês
10.2307/2399098
ISSN2162-4372
AutoresHarold Robinson, A. Michael Powell, Robert M. King, James F. Weedin,
Tópico(s)Botany, Ecology, and Taxonomy Studies
ResumoLimited but strategic knowledge of chromosome numbers in the small, mostly Andean tribe Liabeae includes records of 12 of the 16 genera: Cacosmia (x = 7); Chionopappus (n = ca. 9); Ferreyranthus, Oligactis, and Liabum (x = 18); Sinclairia (x = 16); Paranephelius (x = 9, 14); Pseudonoseris (n = 12?); Erato (x = 9); Philoglossa (n = 18); Chrysactinium (x = 12); Munnozia (n = 10, 11, x = 12). The tribal base number is apparently x = 9 supporting a long, separate history from the diploid elements of Vernonieae (x = 10) in the Eastern Hemisphere. Apparent aneuploid series of the type seen in Munnozia are regarded as reductions from the highest number. No correlation is seen between chromosome number and habit in the tribe. All cytologically known elements of the tribe with extensive distribution beyond the ancestral Ecuadorian-Peruvian area are polyploid. Differences in chromosome number combined with geography provide almost complete generic isolation in the tribe, and no evidence is noted of hybridization between extant genera. The present paper continues a series dealing with chromosome numbers of Compositae (Raven et al., 1960; Raven & Kyhos, 1961; Ornduff et al., 1963, 1967; Payne et al., 1964; Solbrig et al., 1964, 1969, 1972; Anderson et al., 1974; Powell et al., 1974,1975; King et al., 1976; Tomb et al., 1978; Robinson et al., 1981) and is the first dealing with the elements of Liabeae as a united group recognized at tribal level. Because data for the tribe are limited, reports from the literature are included in the table with altered identifications where necessary. New reports are provided for 31 populations of 15 species including new reports for nine species and one genus (marked respectively in Table 1). The new reports in this paper are based on material collected by R. M. King and counted by A. M. Powell and J. F. Weedin. The chromosome counts have been made from aceto-carmine or aceto-orceine squashes of microsporocytes in meiosis. Voucher specimens of the King collections are in US, a second set is in MO. Robinson (1 983a) recognized about 157 species of Liabeae in 15 genera; his paper is the basis for comparison in this paper. The subsequently described monotypic Bishopanthus of Peru (Robinson, 1983b) is unknown cytologically and will not be considered in the present study. In spite of the comparatively small size of the tribe, Liabeae show considerable diversity in many structural details (Robinson & Brettell, 1974) and pollen (Skvarla et al., 1977) which are used as the basis for three subtribes, Liabinae, Paranepheliinae, and Munnoziinae, in the recent revision by Robinson (1983a). Present information indicates that the chromosome base numbers in the tribe are also diverse. They correlate to a considerable extent with the revised generic concepts and show distinctive trends in different subtribes. Previous records of chromosome numbers of Liabeae are scattered and often confusing. Ornduff et al. (1963) offer the only cytological evaluation of Liabeae as a group, but only those parts treated under the traditional concept as subtribe Liabinae in Senecioneae. The traditional disposition, derived from Bentham (1873) and Hoffmann (1894), was totally flawed by the inclusion of foreign elements such as Neurolaena and Schistocarpha, which are now placed in Heliantheae, by the exclusion of true members of Liabeae such as Chionopappus, Cacosmia, and Philoglossa, and by the placement of all remaining members of the tribe in a single genus, Liabum. Ornduff et al. (1963) were able to mention only one chromosome count of a true member of the tribe, a Liabum sp. (L. ovatum vel aff.) reported by Diers (1961) as n = 14. The chromosome counts available in the unnatural group were said by Ornduffet al. to attest to the isolated position of the Liabinae. A number of additional chromosome counts I Department of Botany, National Museum of Natural History, Smithsonian Institution, Washington, D.C. 20560. 2 Department of Biology, Sul Ross State University, Alpine, Texas 79830. 3Community College of Aurora, Aurora, Colorado 80011. ANN. MISSOURI BOT. GARD. 72: 469-479. 1985. This content downloaded from 157.55.39.159 on Sun, 22 May 2016 06:08:55 UTC All use subject to http://about.jstor.org/terms TABLE 1. Chromosome numbers and sources for Liabeae. Species Chromosome Number (n) Locality or Literature Source Cacosmia rugosa H.B.K. 7 (possibly + 1 small fragment) Ecuador. Azuay: ca. 6 km SE of Cumbe, King 6702 7 (bivalents all same size)b Ecuador. Loja: 7 km W of Loja, King & Almeda 7889 Cacosmia rugosa var. kingii H. Robin7 + 1 small fragments Ecuador. Loja: ca. 2 km E of Loja, King 6913 son 7 (bivalents all same size)b Ecuador. Zamora-Chinchipe: 17 km E of Loja, King & Almeda 7929 Chionopappus benthamii S. F. Blake ca. 9 (2n = 18-20) Peru (Diers, 1961) Chrysactinium hieracioides (H.B.K.) H. 12 Peru (Turner et al., 1967; as Liabum) > Robinson & Brettell 12 Peru (Dillon & Turner, 1982) 12-14a Ecuador. Loja: 2 km N of Chinchas, King & Almeda 7962 ca. 12 possibly even 13 (or even 14, 15, 16)a Peru. Cajamarca: 41 km NE of Cajamarca, King & Bishop 9128 13 ? 1 (not clear)a Peru. Amazonas: along road SE of Chachapoyas, King & M Bishop 9200 12 or 13 [in some cells seemingly clear Peru. Amazonas: 40 km SW of Leimebamba, King & Bishop o n = 12; either n = 12 + 1 fragment or 9245 13; 1 very large (or multivalent?); large very clear in some 0 cel sl > 13 ? 1 (in some cells looks like n = 12 or Peru. Amazonas: 23 km S of Tingo, King & Bishop 9273 n= 12 + 1 fragment; possibly 12, 13, or > 14; heteromorphic bivalents make inter0 pretation difficult; 1 large II and varying sizes down to small, some smaller ones even fragment-looking; bridge seen in few Z cells so larger bivalent possibly is a
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