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Download This PDF File 92 Bothalia 24,1 (1994) recognised as one of the principal methods for the forma­ REFERENCES tion of new species among higher plants’, but that the CRON, G.V. 1991. A sy stematic study o f certain species of Cineraria L species originating from this process are usually ‘very (Asteraceae). M.Sc. thesis, University of the Witwatersrand, Jo­ similar to their diploid ancestors in external morphology hannesburg. and ecological preferences’. C. albicans is a highly vari­ DARLINGTON, C.D. & LA COUR, F.L. 1976. The handling of chromo­ able species (Hilliard 1977; Cron 1991) and may well be somes. George Allen & Unwin, London. a species complex or in the process of speciating (Cron DUBININ, N.P. 1940. Darwinism and the genetics of populations. 1991). Characters such as the size and persistence of the Uspekhi Sovremennoi Biologii 13: 276—305. petiolar auricles, the glabrescence of the involucral bracts DYER, R.A. 1963. The use of lactopropionic orcein in rapid squash and the indumentum of the cypselae show great variation. methods for chromosome preparations. Stain Technology 38: 85- 90. (Note: the 'species A' of Hilliard (1977) is here considered GOLDBLATT, P. 1981. Index to plant chaimosome numbers 1975-1978. to be part of C. albicans.) Apparent isolation of popula­ Monographs in Systematic Botany 5. Braun-Brumfield, Ann tions of C. albicans in the gorges comprising valley Arbor, Michigan. bushveld in the Natal midlands and coastal areas, and in GRANT, V.E. 1971. Plant speciation. Columbia University Press, New Transkei has evidently resulted in variability becoming York and London. fixed in certain areas (Dubinin 1940). Similarly, isolation HEDBERG, I. & HEDBERG, O. 1977. Chromosome numbers of on mountain tops in Lesotho, Natal and in the eastern afroalpine and afromontane angiosperms. Botaniska Notiser 130: Cape has resulted in marked variation in the features noted 1-24. above. HILLIARD. O.M. 1977. Compositae in Natal. University of Natal Press, Pietermaritzburg. JEFFREY, C. 1986. The Senecioneae in East tropical Africa. Kew Bulletin C. deltoidea, as described by Jeffrey (1986), is the most 41: 873-943. wide-ranging of the species, occurring in the eastern high­ LOVE, A. & LOVE, D. 1967. Polyploidy and altitude: Mt Washington. lands of Ethiopia, Kenya, Tanzania, and Malawi, the Biologisches Zentralblatt. Supplementary Volume: 307-312. Zoutpansberg in the Transvaal, and the Natal midlands MOORE. R.J. 1973. Index to plant chromosome numbers 1967—1971. and coastal regions of Natal and the Transkei. It is a very Regnum vegetahile 90. Oosthoek’s Uitgeversmaatschappij B.V., variable species, with especially distinctive variants oc­ Utrecht, Netherlands. curring on some mountain massifs (Jeffrey 1986) and it NORDENSTAM, B. 1969. Chromosome studies on South African vascu­ lar plants. Botaniska Notiser 122: 398—408. is therefore not surprising that polyploid populations exist. NORDENSTAM, B. 1977. Senecioneae and Liabeae—systematic re­ view. In V.H. Heywood, J.B. Harbome & B.L. Turner, The biol­ ogy and chemistry of the Compositae. Vol. 2: 799-830. Academic The presence of polyploidy in the genus Cineraria is Press, London and New York. thus confirmed, with a diploid chromosome number of 20 STEBBINS. G.L. 1950. Variation and evolution in plants. Columbia in six species and a polyploid chromosome number of 40 University Press, New York. in three species. TURNER. B.L. & LEWIS, W.H. 1965. Chromosome numbers in the Compositae. IX. African species. Journal of South African Botany 31:207-217. ACKNOWLEDGEMENTS G.V. CRON*. B-E. VAN WYK** and P.L.D. VINCENT* * Department of Botany, University of the Witwatersrand, Private Bag 3, Wits 2050. This work was made possible by bursaries from the ** Department of Botany, Rand Afrikaans University, P.O. Box 524, FRD and the University of the Witwatersrand while the Johannesburg 2000. senior author was reading for an M. Sc. MS. received: 1993-03-01. POACEAE A CYTOTAXONOMIC STUDY OF SOME REPRESENTATIVES OF THE TRIBE CYNODONTEAE (CHLORIDOIDEAE) Poaceae is divided into five major subfamilies. One of MATERIAL AND METHODS these subfamilies, Chloridoideae Rouy, is represented by approximately 50 genera and 232 species in southern Af­ rica (Gibbs Russell et al. 1990). One of the tribes of the The material was collected and fixed in the field. Voucher herbarium specimens are housed in the Geo Potts Chloridoideae, Cynodonteae Dumort., commonly occurs in unstable communities (Clayton & Renvoize 1986). Herbarium, Department of Botany and Genetics, Univer­ Cynodonteae has four subtribes, of which two were stud­ sity of Orange Free State, Bloemfontein (BLFU) or the ied, namely Chloridinae Presl and Zoysiinae Benth. The National Herbarium. Pretoria (PRE). following genera of the subtribe Chloridinae are included in this study: Chloris Sw., Cynodon Rich., Eustachys Desv., Harpochloa Kunth, Microchloa R. Br., and Rendlia SPECIMENS EXAMINED Chiov. The only genus in the subtribe Zoysiinae studied, is Tragus Haller. Chloris gayana Kunth: n = 10. The aim of this study is to establish the chromosome TRANSVAAL.—2428 (Nylstroom): Soutpan Experimental Station, numbers of the different genera and species. (-CD). Spies 3727. 2528 (Pretoria): Sphinx Station, (-CA), Spies 2021. Bothalia 24,1 (1994) 93 C. virgata Swartz: n = 10. Young inflorescences were fixed in Camoy’s fixative ORANGE FREE STATE.— 2827 (Senekal): 6 km from Clocolan to tor 24-48 hours and the fixative was subsequently re­ Peka bridge, (-IX ’). Spies 4799. 2926 (Bloemfontein): on the U.O.F.S. placed by 70% ethanol. Anthers were squashed in 2% campus. (-AA), Spies 5151, 5161, 5164, 5165, 5174', 26 km from aceto-carmine (Darlington & La Cour 1976) and small Dewetsdorp to Hobhouse, (-DB), Spies 4783. aliquots of iron acetate. Slides were made permanent by CAPE— 3026 (Aliwal North): Aliwal North, (-DA), Spies 5245, freezing them with liquid CO2 (Bowen 1956), followed 5249. by dehydration in ethanol and mounting in Euparal. Mei­ otic chromosome behaviour for each specimen, was ex­ Cynodon dactylon (L.) Pers.: n = 18. amined during diakinesis, metaphase 1, anaphase I and CAPE.— 3026 (Aliwal North): Aliwal North, (-DA), Spies 5248. telophase I. At least 20 cells, representative of each of 33Itf (Cape Town): on the top of Botmaskloof Pass, (-BD), Spies 4424. these meiotic stages, were examined per specimen. 3420 (Bredasdorp): IX- Hoop Nature Reserve, (-DC), Spies 4626. RESULTS AND DISCUSSION Eustachyspaspaloides (Vahl) Lanza & Mattei: n = 20. The genus Chloris (Cynodonteae Dumort.; Chloridinae TRANSVAAL.—2530 (Lydenburg): 10 km from Boshoek to Presl) usually has a chromosome base number often, oc­ Buflelsvlei, (-AC). Spies 1521. casionally nine (Gibbs Russell et al. 1990). Both Chloris gayana and C. virgata have somatic chromosome num­ Harpochloa falx (L. f.) Kuntze: n = 20, 25, 30. bers of 20 (Figure 1A-G). We accept that the basic chro­ TRANSVAAL.— 2430 (Pilgrim’s Rest): 4 km from Pilgrim’s Rest to mosome number is ten, because that is the lowest haploid Graskop, (-BA), Spies 5134 (n = 20); 25 km from Sabie to Lydenburg, chromsosome number observed in this study, and de­ (-BA). Spies 5140 (n = 20). 2530 (Lydenburg): Nederhorst turnoff on scribed for this genus. Lydenburg Roossenekal road, (-AA), Spies 5128 (n = 30); 11 km from Dullstroom to Lydenburg via Frischgewaagd, (-AC), Spies 5118 (n = 25); 16 km from Dullstroom to Lydenburg via Frischgewaagd, (-AC), The chromosome numbers published, range from 2n = Spies 5125 (n = 30); 5 km from Belfast to Dullstroom, (-CA), Spies 20 to 40 for C. gayana and from 2n = 14 to 36 for C. 5113 (n = 20). virgata. with 2n = 20 being the most frequent (Darlington ORANGE FREE STATE.—2729 (Volksrust): 53 km from Harrismith & Wylie 1955: Omduff 1967-1969; Fedorov 1969; Moore to Newcastle via Normandien Pass, (-DC), Spies 5063 (n = 20); 92 km 1970, 1971, 1972, 1974, 1977; Goldblatt 1981, 1983, from Hamsmith to Normandien Pass, (-DC). Spies 5065 (n = 20); 97 1985, 1988; Goldblatt & Johnston 1990, 1991). The genus km from Hamsmith to Normandien Pass, (-DC), Spies 5078 (n = 20). Chloris is either diploid, as observed in this study, or poly­ CAPE.— 3027 (Lady Grey): 45 km from Barkly East to Rhodes. ploid, with the polyploid levels ranging from triploid to (-DDl. Spies 3986 (n = 20); 52 km from Rhodes via Lundeansnek, tetraploid (Spies & Jonker 1987). There were almost no (-DD), Spies 4729 (n = 25). 3028 (Matatiele): 65 km from Rhodes via Naudesnek. (-CC), Spies 4695 (n = 20); 69 km from Rhodes. (-CC), meiotic abnormalities in any of the specimens. Spies 4701 (n = 20). 3128 (Umtata): 38 km from Maclear to Elliot, (-AC), Spies 4712 (n = 30). The Cynodon dactylon (Cynodonteae; Chloridinae) specimens studied have haploid chromosome numbers of Microchloa caffra Nees: n = ± 50. 9 (Figure 1H), 18 and 20. The basic chromosome number is nine, because most published chromosome numbers are TRANSVAAL.— 2430 (Pilgrim's Rest): 4 km from Pilgrim's Rest to Graskop. (-BA). Spies 5132', 25 km from Sabie to Lydenburg, (-BA), multiples of nine. These chromosome numbers ranged Spies 5141. 2530 (Lydenburg): 49 km from Lydenburg to Machadodorp. from 2n = 18 to 54 (Darlington & Wylie 1955; Malik (-CB). Spies 5146. 1967; Omduff 1967-1969; Fedorov 1969; Moore 1970- CAPE.— 3128 (Umtata): 38 km from Maclear to Elliot, (-AC), Spies 1977; Goldblatt 1981-1988; Goldblatt & Johnston 1990. 4714. 1991). Malik (1967) described three cytological races in this species: diploid (2n = 18 + 0 - 3B), tetraploid (2n = Rendlia altera (Rendle) Chiov.: n = 20. 36 -1- 0 - 2B) and hexaploid (2n = 54). TRANSVAAL.—2430 (Pilgrim's Rest): 4 km from Pilgrim’s Rest to A few cells of Spies 4626 were diploid and in all these Graskop. (-BA), Spies 5133, 25 km from Sabie to Lydenburg, (-BA), Spies 5142. 2530 (Lydenburg): Nederhorst turnoff on the Lydcnburg- cells some extern of desynapsis occurred (Figure 111). Just Roossenckal rtxkl, (-AA), Spies 5I29\ 11 km from Dullstroom to Lyden­ why desynapsis should occur in the diploid cells, is not burg via Frischgewaagd.
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