Dicoma hindana (Asteraceae), a new species from Somalia

Nord. J. Bot. - Section of tropical taxonomy

Dicoma hindana (Asteraceae), a new species from Somalia Santiago Ortiz and Juan Rodriguez Oubiiia

Ortiz, S . & Oubiiia, J.R. 1995. Dicoma hindana (Asteraceae), a new species from Somalia. - Nord. J. Bot. 15: 187-189. Copenhagen. ISSN 0107-055X.

A new species of the genus Dicoma (sect.Psilocoma), from Somalia, is described. The characteristics by which it can be distinguished from related species are listed. S . Ortiz and J . R . Oubitk, Departamento de Bioloxia Vexetal,Laboratorio de Botanica, Facultade de Farmacia, Universidade de Santiago, E-15706 Santiago de Compostela, Galicia , Spain.

Introduction The genus Dicoma Cass., recently included by Hansen (1991) in the tribe Cynareae and by Bremer (1994) in the tribe Mutisieae, comprises about 45 species - 65 species according to Bremer (1994) - from central and southern Africa and Madagascar. In the course of a monographic study of this genus, we have examined material from a number of herbaria, including BM, COI, K , LUAI and LUAU. Among the K material we found two specimens which had initially been identified as Dicoma somalense S . Moore but whose morphological characteristics did not correspond to those of that taxon. On the basis of detailed study of this material and comparison with D . somalense and related taxa, we consider these specimens to belong to a new taxon, which we describe in this report.

Dicoma hindana Ortiz & Rodriguez-Oubiiia sp. nov. Typus: Somalia, Obbia. 14 October 1912, Drake-Brockman 960 (holotypus: K). Affinis Dicoma somalense S . Moore sed bracteis involucralibus (34)43-60(70), corollis 5 mm longis, antheris 3 mm longis, acheniis longioribus anguste obconicis, pappis setis minoribus differt. Dedicata Dr D.J.N. Hind, Royal Botanic Gardens, Kew, qui in eius generis studio nos adiuvavit.

Species of the section Psilocoma Harv. Perennial shrub about 30 cm high, ramose, leafy. Lower stems woody, medial and upper stems lanate. Leaves (2) 8-18 (19) x (1.2) 2-5 (7) mm, alternate, elliptical to obovate, occasionally spatulate, acute at the tip, subsessile or with basal pseudopetiole, finely araneose, the upper surface covered with inconspicuous sessile glands, the lower surface densely lanate; margin entire or slightly sinuous, somewhat revolute, callose, finely sermlate. Capitula (8) 8.5-9.5 (10) x (9) 10-13 (15) mm, numerous, solitary, terminal, on principal branches or secondary axillary shoots, surrounded by 1-3 (4) scarcely modified leaves of (2) 3-5 (6)x(0.7) 1-2 (2.2) mm. Involucrum campanulate, comprising (34) 43-60 (70) bracts arranged in (4) 5-7 (8) rows. Bracts (1.2) 1.7-7.5 (9)x(0.5) 0.6-1 (1.1) mm, stiffly chartaceous; inner surface glabrous, outer surface moderately araneose-lanate, midrib prominent between two narrow brownish grooves, wide scarious margin irregularly serrulate and frequently torn. Outer bracts small, triangular-subulate, erect-spreading to spreading; inner bracts linear-lanceolate, erect-spreading , more or less squarrose, extending as far as or overtopping the pappus; gradual transition from outer bracts to inner bracts. 10-17 flowers per capitulum. Corolla c. 5 mm, tube 2 mm, lobes 3 mm and revolute at the apex. Anthers 3 mm, appendices 1 mm covered with cilia (generally