Cytology and Systematics of the Moraea fugax Complex (Iridaceae)

Abstract

The Moraea fugax complex, widespread in the winter rainfall area of southern Africa, is treated here as comprising three species, M. gracilenta and the new M. macrocarpa, both of restricted distribution and morphologically and cytologically uniform, and the very widespread and variable M. fugax. The latter comprises two subspecies: larger flowered populations of robust plants with large capsules and one or two channeled leaves are referred to subsp. fugax while small-flowered forms with small capsules and usually two filiform leaves are referred to subsp. filicaulis. Cytologically M. fugax is remarkably variable. Basic chromosome number in Moraea and in the complex is x = 10, and n = 10 is the only number known for M. gracilenta and M. macrocarpa. Moraea fugax subsp. fugax has a base number of x = 10 but exhibits an extensive aneuploid series with populations or races having n = 9, 8, 7, 6, and 5. Subspecies filicaulis has haploid numbers of n = 9, 6, and 5, the former perhaps basic for this taxon. Some correlation of morphological and karyotypic variation suggests that aneuploid decrease occurred in several morphological lines as geographical races differentiated from the ancestral stock during alternating dry and wet phases of the Quarternary. A revised classification ofthe complex is presented in the second half ofthe paper, following a detailed description of the karyological and morphological variation. The karyology of M. fugax is not completely known, but the major features are probably reflected in the data presented here. The Moraea fugax complex (Moraea sect. Subracemosae sensu Goldblatt, 1976a) is one of the most taxonomically complex groups in this pan African genus of some 120 species. Moraea fugax is the major taxon of the section with one or more distinctive segregates sometimes recognized as varieties or separate species. The section has been variously treated in the past as comprising one species and four varieties as in Flora Capensis (Baker, 1896) or as three species (Baker had added two new species to the complex by 1906). In the most recent revision of Moraea in the winter rainfall area of southern Africa, only two species (Goldblatt, 1976b) were recognized, the uniform and local M. gracilenta Goldbl. and the widespread and variable M. fugax (de la Roche) Jacq. [(= M. edulis (L. f.) Ker]. The complex is distinctive in its vegetative habit. The branches are short and often clustered in a semiumbellate manner, and the one or two foliage leaves are inserted near the stem apex at the point of branching, usually well above the ground. The flowers are of the basic type for the genus with large outer tepals marked with nectar guides, smaller inner tepals, and large flattened style branches with well-developed crests, but the capsules are distinctive in having a well-developed beak. Morphological variation is extensive and confusing. Several races can be distinguished in M. fugax but the existence of many intermediates has made recognition of additional species or subspecies difficult and impractical. Since my revision I have had the opportunity to observe and collect members of the complex extensively in the field. As a result I have a deeper understanding of the patterns of morphological variation and have assembled considerably more cytological data. This new information has made a review of the complex necessary. I now recognize three species in the complex: M. gracilenta; the new M. macrocarpa, comprising dwarf, blue-flowered and often unbranched plants with long capsules and nearly sessile spathes; and M. fugax with two subspecies, filicaulis (Baker) Goldbl., including dwarf plants with small, white to cream or rarely blue flowers, small capsules, and stalked spathes, and subsp. fugax for larger flowered, robust plants with either white, blue, or yellow flowers and large capsules. Along the west coast several races or forms of subsp. fugax I Supported by grants DEB 79-10655 and 81-19292 from the United States National Science Foundation. I thank John Rourke and the staff of the Compton Herbarium, Kirstenbosch Botanic Gardens, for their hospitality and help on several field trips in South Africa, especially Dee Snijman, who helped me resolve the problems surrounding the classification of the complex. I also acknowledge with gratitude the collaboration of Margo Branch who provided the plant illustrations used in the paper. 2 B. A. Krukoff Curator of African Botany, Missouri Botanical Garden, P.O. Box 299, St. Louis, Missouri 63 166. ANN. MISSOURI BOT. GARD. 73: 140-157. 1986. This content downloaded from 157.55.39.162 on Thu, 11 Aug 2016 05:30:41 UTC All use subject to http://about.jstor.org/terms 1986] GOLDBLATT-MORAEA FUGAX COMPLEX 141 TABLE 1. Chromosome number and collection information for previously published and original counts presented in this paper for Moraea sect. Subracemosae. Original counts are in bold print. Diploid Number Species (2n) Collection Data M. gracilenta 20 below Piekenierskloof Pass, Goldblatt 3279 (MO). 20 riverside, Clanwilliam campsite, Goldblatt s.n. M. macrocarpa 20 mountains W of Trawal, Goldblatt 5661 (MO); farm Reiers Rus near Worcester, Goldblatt & Snijman 6961 (MO); near Piketberg, Anon s.n. ex hort. Kirsten-