Nordic Journal of Botany zyxwvutsr zyxwvu zyxwvu W Onew species of Dicoma (Asteraceae)from Somalia and Ethiopia Santiago Ortiz and Juan Rodriguez Oubiiia Ortiz, S. & Oubiiia, J. R. 1996. Two new species of Dicoma (Asteraceae) from Somalia and Ethiopia. - Nord. J. Bot. 16: 277-281. Copenhagen. ISSN 0107-055X. Two new species of the genus Dicoma, D. popeana from Somalia and D. aethiopica from Ethiopia, both of the section Psilocoma, are described and illustrated. The two species are distinguished from D. anomala and other similar taxa by a morphologic diagnostic key. S. Ortiz and J. R. Oubitia, Luboratorio de Bioloxia Vexetal, Facultade de Farmacia, Universidade de Santiago, 15706 Santiago de Compostela, Galicia-Spain. Introduction Description We are currently carrying out a revision of the genus Dicoma Cass. (Asteraceae). In the course of this work we have examined material in the K, UPS and ETH herbaria which we consider to belong to two new species, one from Somalia and the other from Ethiopia. The genus Dicoma is conventionally included in the subtribe Gochnatiinae of the tribe Mutisieae (Asteraceae) (Cabrera 1977), although Hansen (1991) in his revision of Mutisieae, has proposed its inclusion in the tribe Cynareae (Cardueae), largely on the basis of the morphology of the petal epidermis, the arrangement of the hairs on the basal part of the achene, the presence of acute sweeping hairs on the style and the presence (at least in some genera) of an evident stylar ring. Recently Bremer (1994) has proposed its inclusion in the tribe Mutisieae as did Cabrera (1977). If, as Hansen (1991) proposes, the genus Dicoma is taken to include the genus Hochstetteria DC., characterized by a pappus comprising a single row of eight to ten squamose pappus bristles, then a total of 40 species of the genus Dicoma are currently recognized. The geographical range of the genus includes areas of southern Asia, tropical and southern Africa and Madagascar. Dicoma popeana S. Ortiz & Rodr. Oubiiia, sp. nov. zyxwvutsr z Accepted 28-2-1995 Typus: Somalia, Jalalaksi District, 12 km NE of Ceel Baraf, 3" 21' N, 45" 49.5' E, elev. ca. 190 m, on gently rolling orange sandhills, in bushland dominated by Commiphora cf. velutina, also Indigofera ruspolii very locally abundant in patches. 14 December 1987, Kuchar 17653 (K, holotype, specimen on the left; UPS, isotype). Planta ad Psilocoma sectionem pertinens. D. anomala et D. aethiopica affinis sed foliis 1.5-2.5 x 0.15-0.3 cm, rugosis, concoloribus, viridibus, similigena pilositate, ex glabra ad moderate tomentosam, in utroque ore, cum pseudopetiolo 1/5-1/3 totus longitudo. Capitula 0.7-0.8 x 0.7-1 nun, disposita in magno numero in longum superioris dimidii plantae, supra ramificationes 1-3 cm; corolla 4-4.5 x 0.7- 1 mm; achaenia pappo 25-40 pilis barbellatis dispositis in 1-2(3) ordinibus, 4-5 pm longis longioribus, leviter laxatis in apice, simis Clare differt. Dedicata Dr G.V. Pope, Royal Botanic Gardens, Kew, qui in nostro studio Dicoma generis nos suasit. zyxwvutsrqp 0 NORDIC JOURNAL OF BOTANY Nord. I. Bot. 16(3) 1996 277 2- zyxwvutsr G 0- cm 1 zyxwvutsrqp zy 098 - D m 0- 278 Nerd. J. Bol. 160) 1996 zyxwvu zyxwvuts zyxwvu Species of the section Psilocoma. Annual, height up to 25 cm; stems highly ramified and moderately tomentose. Leaves 1.5-2.5 x 0.2-0.3 cm, alternate, oval, denticulate, attenuate gradually to a pseudopetiole of length 1/5-1/3 of leaf length, green, concolorous, rugose and of similar pilosity, (slightly to moderately tomentose) on both faces, (though in some cases with the upper surface slightly darker and slightly more glabrescent); yellow sessile glands on the leaf surface. Capitula 0.7-0.8 x 0.7-1 cm, widely cylindrical, abundant on the upper part of the plant, on branches of 1-3 cm with 3-5 small leaves at their base or close to the capitulum; involucral bracts 2.5-8 x 0.5-1.5 mm, arranged in 4-5 rows, linearlanceolate, acuminate-aristate, minutely dentate, the outer bracts narrower and shorter, straw-coloured with a greenish band on each side of the medial nerve, scarcely hairy, especially on the outermost bracts. Flowers tubulose, hermaphrodite, covered with sessile glands; corolla 4-4.5 x 0.7-1 mm; corolla tube 1.5-2.0mm long, with lobes 0.4-0.5 mm wide, apically acute, becoming revolute and with stamens exserted by 0.5- 1 mm at anthesis. Achenes 1.5-2 x 1 mm, turbinated, covered with hairs, these being 0.2-2.5 mm in length white, erect, bifid at the apex; pappus with 25-40 barbellate hairs, these widening slightly towards the tip, blunt, arranged in 1-2(3) rows, the longest 4-5 mm long, the outermost shorter (Fig. 1). mentose. Leaves 1.5-9 x 0.2-1.7 cm, alternate, oval to oblanceolate, denticulate, attenuate gradually to a pseudopetiole of length 1/5-1/3 of leaf length, green, concolorous, rugose and of similar pilosity (slightly to moderately tomentose) on both faces, (though in somecases with the upper surface slightly darker and slightly more glabrescent), unusually wide leaves may be rugose only at their edges; yellow sessile glands on the leaf surface. Capitula 0.8-1.2 x 1.2-2 cm, widely cylindrical, grouped around the top of the plant, on branches of 3-9 cm with 3-5 small leaves at their base or close to the capitulum; involucral bracts 2.5-1 1 x 0.5-1.5 mm, arranged in 4-5 rows, linear-lanceolate, acuminate-aristate, minutely dentate, the outer bracts narrower and shorter, strawcoloured to dark purple with a darker band on each side of the medial nerve, scarcely hairy, specially on the outermost bracts. Flowers tubulose, hermaphrodite, white, covered with sessile glands; corolla 5-8 x 0.7-1.5 mm; corolla tube 2-5 mm long, with lobes 0.4-0.5 mm wide, apically acute, becoming revolute and with stames exerted by 1-2.5 mm at anthesis. Achenes 1.5-2.5 x 0.71.2 mm, turbinated, covered with hairs, these being 0.22.5 mm in length, white to yellowish brown, erect, bifid at the apex; pappus with 40-80(100) barbellatae hairs, these widening slightly at the tip, arranged in 3(4) rows, the longest 4-6 mm long, the outermost shorter (Fig. 2 ) . Additional specimens examined: Ethiopia, Sidamo: Bitata, 20 Km from Negele on the road to Kebre Menhist, 5" 29' N, 39" 28' E, ca. 1450 m, granitic outcrops, with Cornbretum molle, Terminalia brownii, Ozora insignis, Lannaea rivae, etc., 24 April 1983, Gilbert, Ensermu & Vollesen 7781 (K, ETH). Ethiopia, Bale: 13 Km from Ghinir on road to Robi, 7" 05' N, 40" 48' E, 1500 m, Open bushland on red soil, with Commiphora schimperi, Premna sp., Acacia sp., etc., 29 May 1983, Gilbert, Ensermu & Vollesen 7870 (K, ETH). zyxwvutsr zyxwvuts Dicoma aethiopica S. Ortiz & Rodr. Oubiiia, sp. nov. Typus: Ethiopia, Bale A. region, at the Sof Omar caves, about halfway down the gorge on the Ginir-side, 6" 55' N, 40" 5 0 E, ca. 1400 m, in dense Acacia and Commiphora bushland, on limestone. 31 October 1985, Friis, Gilbert & Vollesen 3686 (K, holotype, specimen on the right; ETH, isotype). Planta ad Psilocoma sectionem pertinens. D. anontala et D. popeana affinis sed foliis 2-9 x 0.2-1.5 cm, rugosis, concoloribus, viridibus, similigena pilositate, ex glabra ad moderate tomentosam in utroque ore, cum pseudopetiolo 1/5-1/3 totus longitudo. Capitula 0.8-1.2 x 1.2-2 cm longa, disposita ad apicalem plantae partem, supra ramificationes 3-9 cm; corolla 5-8 x 0.7-1.5 mm; achaenia pappo 40-80(100) pilis barbellatis dispositis in 3(4) ordinibus, 4-6 mm longis longioribus, leviter laxatis in apice Clare differ. Species of the section Psilocoma. Annual or perennial, height up to 40 cm; stems ramified and moderately to- Discussion Dicoma anomala Sond., a polymorphic taxon extending from Cape Province in South Africa to as far north as Zaire and Uganda (Lisowski 1991), is the species which displays the greatest morphological similarity to the two new species described here. However, both new species can be distinguished from D. anomala firstly by their leaves which attenuate gradually to a pseudopetiole of length 1/5- 1/3 of leaf length, are rugose, green, and concolorous (though in some cases with the upper surface slightly darker), and of similar pilosity on both surfaces; the leaves of D. anomala are sessile or with pseudopeti- Fig. I A-F. Dicoma popeana. A. Habit. B. Leaf. C. Capitulum. D. lnvolucral bract. E. Floret. F. Achene with pappus. G . Apex of a pappus hair. - H. Dicoma anomala. Apex of a pappus hair. - A-G based on Kuchar 17653 (K). H based on Gossweiler 3341 (COI). Nwd. 1. 801. 16(3) 1996 279 7 z zy zy z zyxwvutsrqpo C CI -7 nm -0 H 280 Nord. J . Bot. 16(3) 1996 zyxwvutsrq zyxwvutsrqpo zyxwvuts zyxwvuts zyxwvutsr zyxwvutsrq ole length less than 1/10 of leaf length, smooth, discolorous, with the upper surface green, glabrescent or slightly tomentose and the lower surface densely tomentose conferring a whitish colour; secondly by capitulum size (0.7-1.2 x 0.7-2 cm) as opposed to 1.5-2.5 x 1.7-3.5 cm in D. anomala and thirdly by their achenes with pappus of 25-80( 100) hairs, these being widening slightly towards the tip, the longest 4-6 mm long, arranged in 13(4) rows; in D. anomala, the pappus comprises (70)100-120( 150) hairs narrowed towards the tip, acuminate, the longest 7-15 mm long, arranged in 3-5 rows. The following diagnostic key allows the two new species to be differentiated from D. anomala and from two closely related taxa which Pope (1991) recognizes as full species, namely D. gerrardii Harv. ex Wilson (D. anomala var. microcephala Harv., D. anomala f. microcephala (Harv.) Oliv. & Hiern), known from the Republic of South Africa (Harvey 1865; Oliver & Hiern 1877), Namibia (Merxmuller 1967) and Zimbabwe (Wilson 1923), and D. attenuata (S.Moore) Pope (D. trnomala var. attenuata S.Moore), known from Angola, Zambia and Zaire (Pope 1991): I . Leaves sessile or with pseudopetiole length less than I / 10 of leaf length, smooth, discolorous, the upper surface green and generally glabrescent, the lower surface whitish and densely tomentose; achenes with pappus of more than 100 hairs narrowed towards the tip, acuminate, arranged in 3-5 rows, the longest exceeding 7 mm in length ...................................................................... 2 I . Pseudopetiole length 1/5-1/3 of leaf length, leaves rugose, green, concolorous, with similar pilosity on both surfaces; achenes with pappus of less than 100 hairs widening slightly at tip, arranged in 1-3 rows, the longest none exceeding 6 m m in length .............................. 4 3. Involucre smaller than 15 x 15 mm; fewer than 50 involucral bracts, these being narrowly acute and erect ........................................................... D. gerrardii 3. Involucre larger than 15 x 15 mm; more than 50 involucral bracts, these being subulate and erect or apically patent ................................................ D. anomala 4. Leaves 1.5-2.5 x 0.15-0.3 cm; capitula 0.7-0.8 x 0.7-1 cm, abundant on the upper half of the plant, on branches of 1-3 cm length; corolla 4.0-4.5 mm long; achenes with pappus of fewer than 25-40 hairs arranged in 1-2 rows ............................................................ D. popeana 4. Leaves 1.5-9 x 0.2-1.5 cm;.capitula 0.8-1.2 x 1.2-2 cm grouped around the top of the plant, on branches of 3-9 cm length; corolla 5-8 mm long; achenes with pappus of 40-80 hairs arranged in 3 rows ............D. aethiopica Acknowledgements - Our thanks to doctors G. V. Pope and D. J. N. Hind for their invaluable advice, to J. G. Novo for the Latin diagnoses, to M. Guitiin for the illustrations and to the Curators of the herbaria studied for this paper. References Bremer, K. 1994. Asteraceae. Cladistics & Classification. Timber Press, Portland, Oregon Cabrera, A. L. 1977. Mutisieae, systematic review. - In: Heywood, V. H., Harborne, J. B., Turner, B. L. (eds), The Biology and chemistry of the Compositae. 11. Academic Press, London, pp. 1093-1066. Hansen, H. V. 1991. Phylogenetic studies in Compositae tribe Mutisieae. - Opera Bot. 109: 5-50. Lisowski, S. 1991. Les Asteraceae dans la Flore d’Africa Centrale. - Fragmenta floristica et geobotanica 36 ( I ) , Suppl. 1 : 25 1-627. Oliver, D. & Hiern, W. P. 1877. Compositae. - In: Oliver, D. (ed.), Flora of tropical Africa 3. Reeve and Co., London, pp. 253-461. Pope, G. V. 1991. Notes on Dicomu Cass. (Compositae). Kew Bulletin 46: 699-709. Wilson, F. C. 1923. Revision of the genus Dicoma. - Bulletin of miscellaneous information, Kew 1923: 377-388. zyxwvuts 2. Plant rigidly cespitose, simple stems with a single capitulum; leaves linear and revolute .........D. attenuafa 2. Plant slender, cespitose or not, ramified stems, various capitula; leaves oval-lanceolate, not revolute ...............3 Fig. 2 A-F. Dicoma aethiopica. A. Habit. B. Leaf. C. Capitulum. D. Involucral bract. E. Floret. F.Achene with pappus. G. Apex of a pappus hair. - 1 H. Dicoma anomala. Apex of a pappus hair. - A-G based on Friis, Gilbert & Vollesen 3686 (K). H. based on Gossweiler 3341 (COI). Nord. J . Bot. 16(3) 1996 28 1