Chromosome Numbers and Karyotypes in the ...

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C. variabilis J.Everett & Joy Thomps. 44. Connors Hill, Snowy Mtns Hwy, NSW, ..... Marble Bar, W A, Short 4262; Tom Price,. WA, Short 4289. S. liatroides (Turcz.) ...
2 I December 1999

Australian Systematic Botany 12, 781-802

Chromosome Numbers and Karyotypes in the Australian Gnaphalieae and Plucheeae (Asteraceae)* K. WatanabeA,E, P. S. ShortB, T. Denda C, N. Konishi A, M Ito D and K. Kosuge A ADepartment of Biology, Faculty of Science, Kobe University, Kobe, 657-8501, Japan. BHerbarium of the Northern Territory, PO Box 496, Palmerston, NT 0831, Australia. CLaboratory of Ecology and Systematics, College of Science, University of Ryukyu, Okinawa Pref., 903-8501, Japan. DDepartment of Biology, Faculty of Science, Chiba University, Chiba, 260-8501, Japan. ECorresponding author; email: [email protected]

Abstract Chromosome number determinations from 152 collections representing 42 genera and 106 species of the Australian Gnaphalieae and Plucheeae are reported. The chromosome numbers of 75 of these species have not been previously counted or differ from those previously reported for species. Chromosome numbers have been documented for the first time for 14 genera: Argyroglottis (n = 12), Cephalosorus (2n = 24), Decazesia (n = 14), Dielitzia (2n = 26), Eriochlamys (n = 14), ErymophyUum (n = 11 and 14), Gilruthia (n = 13), Leucochrysum (n = 9), Myriocephalus s. str. (n = 14, 2n = 24), Polycalymma s. str. (n = 14), Pterocaulon (n = 10), Pterochaeta (n = 12), Quinetia (2n = 24) and Sondottia (2n = 6). Remaining counts augment and agree with previously reported determinations. Some problems with generic delimitation and interpretation of chromosome data are outlined. There is an array of karyotypes within the Australian Gnaphalieae and dysploidy is widespread. Polyploidy has also played an important role in the evolution of some taxa. Evidence suggests that the base number for Australian Gnaphalieae is x = 14. This may be the base number for the entire tribe.

Introduction

In a recent census of Australian vascular plants 83 I native species of Asteraceae were listed under c. 130 genera (Hnatiuk 1990). Following the tribal concepts of Anderberg (1989, 1991a, 1991b, 1994a, 1994b, 1996) about 338 species and 61 recognised genera belonging to the tribe Gnaphalieae, and c. 30 species and eight genera belonging to the tribe Plucheeae, occur in Australia. Data from a recent compilation (Short 1994) show that chromosome numbers were known for only about 61% (37) of genera and 25% (84) of species of Australian Gnaphalieae, and just one genus and one species in the subtribe Plucheeae. Furthermore, for most of these taxa chromosome numbers were known from single determinations. As previously noted (Short 1994) from the essentially pioneering studies in chromosome numbers in Australian Asteraceae by Turner (1967, 1970) and Short (1986a, 1986b, 1990) which revealed"widely distributed aneuploidy and polyploidy, it is evident that genera of Australian Gnaphalieae are prime candidates for further cytoevolutionary studies. Indeed, with so many taxa remaining to be examined there is much scope for additional cytological studies in both Gnaphalieae and Plucheeae and the results of recent work are reported here. We note that recent analyses (Bayer and Starr 1998) of two non-coding chloroplast sequences, the trnL intron and trnLltrnF intergenic spacer, support the recognition of the Gnaphalieae as defined by Anderberg (l.c.) and followed here, but indicate that circumscription of the Plucheeae is problematic.

*This paper is dedicated to the memory of the late Emeritus Professor S. Smith-White, a pioneer of plant karyological studies in Australia.

© CSIRO 1999

1030-1887/99/060781

782

K. Watanabe et af.

Materials and Methods Chromosome counts were obtained from either floral buds fixed in the field, or root tips obtained from seedlings grown from fruit of known provenance in the greenhouse of Kobe University. The procedures of Watanabe et al. (J 975) were followed for the cultivation of plants and the preparation of material for chromosome number deterininations. A complete set of voucher specimens has been deposited in MEL. Duplicate voucher collections of non-Victorian populations have been, or will be, deposited in the major herbaria (AD, DNA, BRI, NSW, PERTH) of the State from which collections were gathered. An incomplete set has been deposited with TI. Illustrations of karyotypic idiograms are based on the means of 10 measurements for each chromosome.

Results and Discussion Our chromosome number determinations from 152 collections attributed to 42 genera and 106 species, together with previously published determinations (e.g. Turner 1967, 1970; Short 1986a) of chromosome numbers of the Australian Gnaphalieae and Plucheeae, are presented in Table 1. Photomicrographs of the mitotic chromosomes of eight species are displayed in Figs 1-8 and idiograms of the mitotic chromosomes of 10 species are displayed in Figs 9-18. The characteristics of the karyotypes of 10 species are presented in Table 2. A summary of chromosome numbers in Australian genera of Gnaphalieae is provided in Table 3 and a summary of chromosome numbers for all genera of Gnaphalieae (excluding Angianthinae) is provided in Table 4. Our results include reports of chromosome numbers for 14 genera and 67 species that have not been previously counted, or were only known from approximate counts (e.g. Quinetia, Ixiolaena lep to lep is). It also includes chromosome numbers for eight species for which our counts differ from those previously reported. Excluding approximate counts, the number of cytologically determined species of AUStralian Gnaphalieae is now 144 (c. 42 %) and covers 54 (c. 89 %) of the genera currently recognised. Within the Australian Plucheeae numbers are now known for three of the eight genera and for 9 of the c. 30 recognised species. Classification and Chromosomes Generic delimitation within the Australian Gnaphalieae has been a long-standing problem. Bentham (1867), with little or no justification, reduced to synonymy many of the small genera recognised by his contemporaries and created often unwieldy, clearly nonmonophyletic genera. The problem of generic delimitation has been and is being addressed by taxonomists (e.g. Short 1983, 1986b, 1990; Wilson 1989, 1992a, 1992b, 1992c). Cladistic analyses, mainly by Anderberg (l991a, 1991b, 1994b), indicate possible relationships of genera but much remains to be done. For example, in regard to genera listed in Table 1, morphological evidence (Short, unpubl.) indicates that at least several additional genera should be segregated from each of Calocephalus, Gnephosis, Myriocephalus, Podolepis and Rhodanthe. The generic placement of some Australian species currently and erroneously referred to Helichrysum and Helipterum also needs to be resolved. Meaningful discussion of patterns of chromosomal evolution in plant groups is dependent upon good classifications. The taxonomic concepts that are being followed must be made clear. It is therefore instructive to comment further upon the delimitation of some genera of Australian Gnaphalieae for which chromosome numbers are known. Calocephalus s. lat. Until recently, about 20 species have been referred to this genus. Short (1987) reinstated Blennospora (n = II) and several others are now referred to Leucophyta (n = 9), Gilrllthia (n = 13) and Gnephosis s. str. (n = 14, 13, 12, 11,6) (e.g. Anderberg 1991a). This still leaves approximately 12 species within the genus and it is clear that they too are not congeneric. Of the four species cited in Table I only C. citreus (n = 28) belongs to Calocephalus s. str., features including fruit and corolla morphology (Short 1987, unpubl.), indicating that the remaining three (C.jrancisii, n = c. 14; c. knappii, n = 14; C. platycephalus n = 12) are generically distinct from c.' citreus. In Table 3 these three are referred t9 the 'c. knappii group'.

783

Karyotypes of Australian Gnaphalieae and Plucheeae

Table I. Summary of chromosome numbers in species of Australian Gnaphalieae and Plucheeae Numbers in brackets indicate the total number of species believed to occur in the genus. Chromosome numbers in bold are for taxa for which chromosome numbers have not been previously reported or for which our determinations are different to those previously reported for a taxon. Numbers in bold italic are new counts that substantiate past determinations. References are provided for past counts. Collection data are provided for all new counts and those substantiating past counts Genus and species

n

2n

References and/or collection data

Gnaphalieae

Actillobole Fenzl ex End!. (4) A. drummondiana P.S.Short A. uliginosum (A.Gray) H.Eichler

Turner 1970, as Gnaphalodes condensatum Short 1985

c. 11 or 1211

AlIllllObill11l R.Br. (2) A. alatum R.Br.

26 Allgianthlls Wend!. (c. 20) A. acrohyalillus Morrison

Mauds Landing near Coral Bay, WA, Short 4320 Turner 1970, as A. tomentosus; Lake Annean, WA, Short 4231 Preston Beach, WA, Short 4565 Turner 1970; Carnamah, W A Short 4068; Balladonia, WA, Watanabe 340; Pt Augusta, SA Watanabe 329; Ceduna, SA, Watanabe 336 Lake Austin, WA, Short 4220

A. milnei Benth. A. preiss ian us (Steetz) Benth. A. tomentosus Wend!.

A. unijlorus P.S.Short Argentipallilll1l Paul G.Wilson (6) A. niveum (Steetz) Paul G.Wilson

c.12 11

Turner 1970, as 'Helipterum obtusifolium'

Argyroglottis Turcz. (I) A. turbinata Turcz.

Lake King, WA, Short 4536

Asteridea Lind!. (11) A. asterioides (Turcz.) Kroner A. athrixioides (Sond. & F.Muel!.) Kroner

Cataby, WA, Short 4519 Turner 1970, as Athrixia athrixioides; Short 1986a; Lake Biddy, WA, Short 1730; Yellowdine, WA, Short 1756; Marvel Loch, WA, Short 4446; Esperance, WA, Watanabe 180 Lake Austin, WA, Short 4224

A. chaetopoda (F.Muel!.) Kroner Bellida Ewart (I) B. graminea Ewart BlellllOspora A.Gray (? 3) B. drllmmondii A.Gray B. phlegmatocarpa (Diels) P.S.Short Bractealltha Anderb. & Haegi (5+) B. bracteata (Vent.) Anderb. & Haegi

Sugiura 1931,1936 Avanzi 1948; Uralla, NSW, Ito 96003

Turner 1970

1111

22 22

Short 1981, 1987 Short 1981, 1987

1411 1211

24

Turner 1970, as Helichrysum bracteatllm Horsham, Vic., Watanabe 218; Polblue Swamp, NS,w, Ito 96026

K. Watanabe et at.

784

Table 1.

(continued)

Genus and species

Ca/ocep/w/us R.Br. s. lat. (c. 12) C. francisii Benth. C. knappii (F.Muell.) Ewart & Jean White C. platycephalus (F.Muell.) Benth. Ca/oceplta/us s. str. (c. 3) C. citreus Less.

Ceplta/ipteru11l A.Gray (I) C. drummondii A.Gray

n

2n

c.14 11 1411

Turner 1970 Beasley Creek, W A, Short 4413

1211

Alice Springs, NT, Watanabe 670

28 11 (0-2IV)

Derrimut Grasslands, Vic., Short 4573

1211 1411

Turner 1970 Turner 1970

Ceplta/osorus A.Gray (1) C. carpesiaides (Turcz.) P.S.Short Cltrysoceplta/ulll Walp. (c. 10+) C. aff. adpressum W.Fitzg. C. apiculatum (Labill.) Steetz

24

C. semipapposum (Labill.) Steetz Chrysacephalum sp.

Craspedia G.Forst. (c. 40) C. a/pina Backh. C. aurantia J.Everett & Joy Thomps. C. canens J.Everett & Joy Thomps. C. glauca (Labill.) Spreng. C. uniflara Labill. s . lat.

c. 38 11 c. 38 11

c.401 1211 1211

Turner 1970, as Leptorhynchus ambiguus Oodla Wirra, SA, Watanabe 196 Karijini National Park, W A, Short 4278

24

110 44 66 44 1111 70+ 11

C. variabilis J.Everett & Joy Thomps.

Craspedia sp. I

44 22 11 , c. 33 11 -

Craspedia sp. 2 Decazesia F.Muell. (I) D. hecatocephala F.Muell.

Three Springs, WA, Short 4505

Mt Magnet, WA, Short 4201 Turner 1970, as Helichrysum apiculatum; Kyancutta, SA, Watanabe 332; DeniIiquin, NSW, Watanabe 602 Naracoorte, SA, Watanabe 304; Wilpena Pound, SA, Watanabe 314; Derrimut Grasslands, Vic., Short 4575 Turner 1970 Turner 1970, as Leplorhynchus ambiguus

2411 1211

2411

C. semicalvum (F.Muell.) Paul G.Wilson

References and/or collection data

22

Nanuttarra Roadhouse, WA, Short 4300

1411

Dielitzia P.S.Short (I) D. tysanii P.S.Short

Dawson et al. 1999 Thredbo, NSW, Ito 96048 Derrimut Grasslands, Vic., Short 4571 Dawson et al. 1999 Turner 1970 Turner 1970 Connors Hill, Snowy Mtns Hwy, NSW, Ito 96070 Y ornup, W A, Short 1661--