Taxonomic Notes on the Genus Zantedeschia Spreng. (Araceae) in Southern Africa

S. Afr. J. Bot. 1996, 62(6) 321

Taxonomic notes on the genus Zantedeschia Spreng. (Araceae) in southern Africa

Y. Singh,* A.E. van Wyk1 and H. Baijnath2 *Natal Herbarium, National Botanical Institute, Botanic Gardens Road, Durban, 4001 Republic or South Africa 1H.G.W.J. Schweickerdt Herbarium, Department or Botany, University of Pretoria, Pretoria, 0001 Republic or South Africa 2 Ward Herbarium, Department or Botany, University of Durban-Westville, Durban, 4000 Republic of South Africa

Received 23 November 1995; revised 15 August 1996

A taxonomic re-assessment of Zantedeschia revealed that Z a/bomaculata subsp. va/ida is markedly distinct rrom Z a/bomaculata subsp. albomacu/ata and Z. albomaculata subsp. macrocarpa. Differences in morphology proved to be s ufficient to exclude it from the Z albomaculata complex, and to recognize it at specific level as Z valida. The history of the classification of Z a/bomaculata is briefly reviewed. This study further supports the delimitation of species into two sections: Zantedesch/a and Aestivae. A key to sections, species and s ubspecies, based on macromorphology and geographical distribution, is presented.

Keywords: Aestivae, Araceae, distribution , macromorphology, taxonomy, Zantedeschia.

*To whom correspondence should be addressed.

Introduction spotted leaves and a deep purple throat at the base of the spathe, Zantedeschia Spreng. (Arum or Calla lilies), a relatively small introduced from Natal by Messrs Backhouse of York (England) genus of eight species, forms the tribe Zantedeschieae in the sub (Watson 1892). Subsequently, Calla oculata Lind!. (1859), Rich family Philodendroideae (sensu Bogner & Nicolson 1991). The ardia hastata Hook. (1860), R. angustiloba Schott (1865), R. genus is confined to southern Africa, including Angola, Zambia, melanoleuca Hook. (1869) and Zantedeschia macrocarpa Engl. Malawi, Zimbabwe and Tanzania. (1883) were described as separate species; all based on rather Showy and decorative hybrids and varieties of Zantedeschia similar-looking material. In Engler's revision of the genus in have drawn much interest among plant breeders abroad, where 1915, Z. a/bomaculata, Z. angustiloba, Z. macrocarpa, Z. mela tubers, cut flowers and container plants form the basis of a lucra noleuca and Z. oculata (Lind!.) Engl. were among the eight spe tive export industry in the USA, the Netherlands and New Zea cies recognized. Engler treated Z. hastata Hook. as a synonym of land. Z. oculata. Traub (1948) upheld these species, but regarded Z. oculata as a synonym of ltastata. Letty (1973) proposed three The previous revision of Zantedeschia was by Letty (1973) Z. who recognized six species. She divided the species into two subspecies of Z. albomaculata, based on leaf lamina shape. She informal sections with Z. aethiopica as the sole member of the considered Z. albomaculata, Z. angustiloba, Z. ltastata, Z. mela typical section, and the remaining species were assigned to a sec noleuca and Z. oculata as synonyms of Z. albomaculata subsp. ond section, for which she did not suggest a name. Furthermore, a/bomaculata and reduced Z. macrocarpa to Z. albomaculata Letty ( 1973) recognized three subspecies of Z. albomaculata, subsp. macrocarpa. Letty further described a new subspecies, Z. albomaculata subsp. valida, from Natal (now the KwaZulu namely Z. albomaculata (Hook.) Bail!. subsp. albomaculata, Z. Natal Province). albomaculata subsp. macrocarpa (Engl.) Letty and Z. albomacu lata subsp. valida Letty. In the present treatment, the cordate base of the leaf lamina and the funnel-shaped spathes of sub-spe Diagnostic characters cies valida are considered to be evidently anomalous in the Z. Characters useful in defining species of Zantedeschia include albomaculata group, and it is on this basis that the subspecies is lamina shape, degree of maculation, spathe shape and colour, raised to species level. In addition, the two sections implied by presence or absence of staminodes among ovaries, fruit colora Letty are formally described as Zantedeschia and Aestivae. tion on ripening and geographic distribution (Singh et al. 1995). Select morphological characters and distribution of Z. valida Materials and Methods and the subspecies of Z. albomaculata are compared in Table I The present study is based on extensive observations of plants in the (see also Figures 1-3). Leaf laminae of Z. a/bomaculata are field and in cultivation. Plants obtained from several wild popula oblong-ovate to triangular-hastate, whereas in Z. valida, laminae tions throughout South Africa were transplanted and kept in cultiva are ovate to orbicular with cordate bases. In Z. albomaculata tion under greenhouse conditions to ensure adequate material for a subsp. a/bomaculata, leaf laminae may b.e immaculate or densely thorough morphological investigation. Voucher herbarium speci maculate, those of Z. albomaculata subsp. macrocarpa are mens are deposited in the Natal Herbarium (Durban; NH). In addi sparsely maculate or occasionally immaculate while in Z. valida, tion, collections from the Nati onal Herbarium (Pretoria; PRE), laminae are rarely maculate. Since all three taxa may produce Malolotja Nature Reserve Herbarium (Swaziland; SWZ), National maculate laminae, the presence of maculation is an unreliable University of Lesotho Herbariu m (Lesotho; ROML) and National character for separating these taxa. Herbarium and Botanic Gardens (Zimbabwe; SRGH) were studied. Spathes of Z. albomaculata are cy lindrical (Figure Sa) where as those of Z. valida are funnel-shaped (Figure 5b). Spathe col Results and Discussion our of the typical subspecies varies from white, ivory, cream, and Z. albomaculata complex pale yellow to coral pink. Spathes of Z. albomaculata subsp. In 1859, Z. albomaculata was described by W.J. Hooker as Rich macrocarpa are cream and those of Z. valida are white. ardia a/bo-maculata Hook. The name was based on a plant with Z. albomaculata subsp. albomaculata is widespread in the 322 S. Afr. J. Bot. 1996, 62(6)

Figures 1- 3 1. Z. albomaculata subsp. albomaculata. 2. Z. albomaculata subsp. macrocarpa. 3. Z valida. S. Afr. J. Bot. 1996, 62(6) 323

Table 1 Comparison of select morphological characters in Z. valida and the subspecies of Z. a/bomaculata Z. a/bomaculata z. valida

(= Z. albomaculata Characters subsp. albomacu/ata subsp. macrocarpa subsp. valida) Figure I Figure 2 Figure 3 Leaf lamina shape oblong to ovate-hastate triangular-hastate ovate to orbicular-cordate Degree of lamina immaculate or densely maculate sparsely maculate or occasionally immaculate or rarely maculate maculation immaculate Spathe shape cylindrical, limb recurving, cylindrical, limb upright, truncate funnel -shaped. limb spreading, tapering to apex at apex truncate at apex Spathe white, ivory, cream, pale yellow cream white colour or coral pink Distribution Widespread in eastern parts of South Africa and Swaziland South Africa, confined to a South Africa, also in Lesotho, restricted area in KwaZulu-Natal Swaziland, Zambia, Zimbabwe, Angola, Malawi and Tanzania eastern parts of South Africa and it also occurs in Lesotho, Swa spathe shape of Z. albomaculata subsp. albomaculata approach ziland, Zambia, Zimbabwe, Angola, Malawi and Tanzania. Sub es that of Z. albomaculata subsp. macrocarpa and vice versa, species macrocarpa occurs in South Africa and Swaziland. Z. with some specimens having a combination of characters from valida is confined to a restricted area in KwaZulu-Natal in South both subspecies. Recognition of these two taxa at subspecific Africa (Figure 4). Morphological distinction of Z. valida is sup level is therefore retained. Suspected hybridization between the ported by its geographical isolation, being restricted to the area two subspecies may explain specimens displaying characters of bordered by the Biggarsberg (2829BB), Giant's Castle (2929AD) both subspecies. and Collin's Pass (2829BA) in KwaZulu-Natal. Z. albomaculata subsp. macrocarpa differs from Z. albomacu Zantedeschia valida (Letty) Y. Singh, stat. nov. lata subsp. albomaculata in having triangular-hastate and sparse ly maculate leaves, cream-coloured spathes that are truncate at Zantedeschia albomaculata (Hook.) Baill. subsp. valida Letty, the apex and relatively few, large berries. This study confirms the Bothalia 11: 25 (1973). Type: Natal (2829 BD), farm Blanerne, observations by Letty (1973) that in a few instances, lamina or 29 km N. of Ladysmith, Letty 492 (holotype PRE!).

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Figure 4 Distribution of Z. albomaculata and Z. valida in southern Africa. •, Z. albomaculata subsp. albomaculata; o, z. albomacu lata subsp. macrocarpa; Y, Z. valida. 324 S. Afr. J. Bot. 1996, 62(6)

restricted to ovaries in zone between male and female); entire spathe . turns green during berry maturation; inflorescence non-scented; summer rainfall region of southern Africa [ii. Section Aestivae] •••.•••...... •. • •...•••• • •. • ..•..•• 3 3a Spathe funnel-shaped, interior with a purple-coloured blotch at base • ..•• •••••• •• .. .• .•...... •••.••.••...... 4 3b Spathe cylindrical. interior with or without a purple-coloured blotch at base ••. .•. . . . .• . . ...•.. . •••.••• . •.....• . 7 4a Spathe white; leaf lamina ovate to orbicular cordate ...... Z valida 4b Spathe yellow; leaf lamina variously shaped ...... 5 Sa Leaf lamina usually immaculate, oblong-hastate, glaucous green ...... Z. pentlandii Sb Leaf lamina always maculate, triangular-hastate to ovate-orbicular, deep green .••. . •••••••••.. . .••• 6 6a Leaf lamina triangular-hastate ...... Z. juczmda 6b Leaf lamina ovate-orbicular ...... Z. elliotiana 7a Leaf lamina oblong, ovate or triangular-hastate . . 8 a b , ';. Sa Leaf lamina oblong to ovate-hastate; spathe tapering to the apex ...... Figure 5 Spathe shapes. a, Z. albomaculata subsp. albomacu ...... Z. albomaculata subsp. albomaculata Lata, cylindrical. Scale bar= 8 mm. b, Z. valida, funnel-shaped. 8b Leaf lamina triangular-hastate; spathe truncate Scale bar= 8 mm. at the apex ...... Z. albomaculata subsp. macrocarpa 7b Leaf lamina narrowly lanceolate, cuneate at base . Section Zantedeschia ...... Z. re/unannii Diagnostic characters as in key. This section conforms to the typical section informally suggested Acknowledgements by Letty (1973) and includes Z. aethiopica and Z. odorata. This study was funded in part by the University of Pretoria and the National Botanical Institute. Mr and Mrs Mitcheii-Innes are Section Aestivae Y. Singh sect. nov. thanked for their hospi tality during field work. We would like to Tuber discoideum; spatha intus basin versus cum vel sine macula thank the Directors and staff of SWZ, ROML and SRGH for the purpurea; ovariae plerumque sine staminodis (si praesentia nunc loan of herbarium specimens, Dr H. Glen (PRE) for the Latin solum in zona transitionis inter antheras et ovaria); tote spatha viri translation and Dr D.H. Nicolson (US) for advice on nomencla descit dum baccae maturant; non odorata; plantae crescunt in ture. regione pluviae aestivae Austro-africana. References TYPUS.-Z. jucunda Letty. BOGNER, J. & NICOLSON, D.H . 1991. A revised classification of Key to sections, species and subspecies of Zantedeschia Araceae with dichotomous keys . Willdcnowia 21: 35-50. ENGLER, H.G.A . 1883. Bot. Jb. 4: 63. Ia Tuber rhizomatous; spathe interior without a purple-coloured ENGLER, H.G.A. 1915. Tribus V. Zantedeschieae. Pflanzenreich IV: blotch at base; ovary surrounded by 3 spathulate staminodes; 61-69. lower portion of spathe turns green while upper portion withers HOOKER, W.J. 1859. Richardia albo-maculata. Curtis's Bot. Mag. t. away during berry maturation; inflorescence scented; summer 5140. [i. and/or winter rainfall regions of southern Africa Section HOOKER, W.J. 1860. Richardia ltastata. Curtis's Bot. Mag t. 5176. Zantedeschia] • .•• . ..•••••.•••• •• •••••• • •••••••• • •.•• 2 HOOKER, J.D. t869. Richardia melanoleuca. Curtis's 801. Mag. l. 2a Spathe funnel-shaped; spadix 50-75 mm long, 5-7 mm 5765. wide; peduncle erect during fruiti ng; berries tum orange and LINDLEY, J. 1859. New plants. Calla oculata. Gdnrs' Clmm. 40: 788. soft when ripe; widespread in South Africa . ..Z. aethiopica LETTY, C. 1973. The genus Zantedesd!ia. Bothalia II: 5-26. 2b Spathe cylindrical; spadix 25-35 mm long, 5-10 mm wide; SCHOTT, H.W. 1865. Rid1ardia angustiloba Schott. J. Bot. 3: 35. peduncle bending to the ground during fruiting; berries SINGH, Y., VAN WYK. A.B. & BAIJNATH, H. 1995. Know your remain green and firm when ripe; restricted to the arums: n comparative guide to the members of the genus Zantede Nieuwoudtville District in the Western Cape .... Z. odorata schia. Veld Flora 81: 54-55. lb Tuber discoid; spathe interior with or without a purple-coloured TRAUB , H.P. 1948. The genus Zantedeschia. Pl. Life 4: 9- 32. blotch at base: ovaries usually lacking staminodes (if present, WATSON, W 1892. Richardias. Gdnrs' Chmn. 12: 23-124.