The Taraxacum Flora of the Sierra De Guadarrama and Its Surroundings (Spain)
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THE TARAXACUM FLORA OF THE SIERRA DE GUADARRAMA AND ITS SURROUNDINGS (SPAIN) by ADRIÁN J. RICHARDS* Resumen RICHARDS. A. J. (1992). Los Taraxacum de la Sierra de Guadarrama y aledaños (España). Anales Jard. Bot. Madrid 50(2): 201-208 (en inglés). De la Sierra de Guadarrama y aledaños se citan 18 especies agamospermas pertenecientes a seis secciones del género Taraxacum. Cinco de las especies son novedades para la Península Ibérica: tres de ellas no habían sido citadas y otras dos — T. navacerradense (sect. Alpestria) y T. nietoi (sect. Céltica) — se describen aquí como nuevas. En esta región casi todos los Tara- xacum parecen ser agamospermos. Solamente se ha encontrado uno sexual, de carácter adventicio. Palabras clave: Taraxacum, taxonomía, agamospermia, España. Abstract RICHARDS, A. J. (1992). The Taraxacum flora of the Sierra de Guadarrama and its surround- ings (Spain). Anales Jard. Bot. Madrid 50(2): 201-208. Eighteen native agamospermous species of Taraxacum are reported from the Sierra de Gua- darrama and its surroundings. These are classified amongst six sections of the genus. Three species are recorded from Spain for the first time, and in addition two new species are des- cribed, T. navacerradense (sect. Alpestria) and T. nietoi (sect. Céltica). In this región it seems that almost all Taraxacum are agamospermous. Only a single specimen of an adventive sexual was discovered. Key words: Taraxacum, taxonomy, agamospermy. Spain. INTRODUCTION these have been described as 'species'. Such plants sometimes lack pollen. Taraxacum (Asteraceae-Cichorieae) is a However, in some regions, including panglobal, although mostly non-tropical, many lowland parts of southern Europe, genus of rosette-forming perennial herbs. plants are mostly sexual outcrossers. Such Many species are of ruderal habit, and can populations are much more variable than is form noxious weeds. However, within a round for the sexuals, and taxonomically región it is typical to find adventive species they can only usually be treated at sectional in anthropogenous habitats, and 'native' rank. species in seminatural habitats. The majo- As yet, little is known of the taxonomy, rity (90%) of species are agamospermous, or the distribution of asexual and sexual with a diplosporous parthenogenesis (RI- Taraxacum, in most of Spain. There has CHARDS, 1973). Many narrowly delimit- been work by V. SOEST (1948, 1951, 1952, ed asexual Unes occur, and some 2000 of 1954a,b,c, 1955,1966,1970,1972), SAHLIN * Department of Agricultural and Environmental Sciences, Ridley Building, University of Newcastle upon Tyne NE1 7RU, United Kingdom. 202 ANALES JARDÍN BOTÁNICO DE MADRID, 50(2) 1992 (1981, 1984) and SONCK (1983, 1985) from lia Kirschner, 0Ugaard and Stepanek. This the Pyrenees, northern and western Spain was discovered growing in the lorry park and Portugal. However, the only collec- on the Puerto de Somosierra (route N-I), tions from the central región of Spain seem where it was almost certainly adventive. to have been by LINDBERG (1932), who des- This was the only sexual individual encoun- cribed six species from near the railway sta- tered; all the Taraxaca from seminatural tion at Aranjuez ('prope urbem Madrid'). habitats in the Sierra de Madrid were ase- In fact although Aranjuez lies within the xual. It seems as if, as is also the case in Comunidad de Madrid, it lies some 50 km to Greece and other southern Mediterranean the south, on the river Tajo. áreas where Taraxacum is largely montane, In late May, 1990,1 was invited to give an central Spain lies to the south of the sexual address at II Jomadas de Taxonomía Vege- zone. tal at the Real Jardín Botánico, Madrid. A systematic list follows with com- Through the kind offices of Dr. Nieto Feli- ments: ner, I was able to spend three days collect- ing Taraxacum in the Sierra de Guadarra- ma, Somosierra and Sierra de Ayllón to the Taraxacum sect. Obovata V. Soest north of Madrid. In all I collected 38 num- bers, some in considerable quantity. The T. obovatum (Willd.) DC. main collections reside with the Real Jar- MADRID: Puerto de Navacerrada, wet road bank in dín, Madrid (MA), but duplicates have Pinus sylvestris forest, 1000 m, 21-V-1990, A. J. been kept by the author, and have been dis- Richards 90/25. SEGOVIA: 1 km west of Casia, limestone, 22-V-1990, A. J. Richards 90/12. tributed to the taraxacologists H. 011gaard (Denmark), J. Stepanek and J. Kirschner As Lindberg and others have noted, very (Czechoslovakia) and C.-E. Sonck (Fin- variable in leaf-morphology, and achene land). colour (grey and red), even in one popu- Most taxa recorded here are very little lation, but apparently asexual. The Nava- known and poorly understood. Conse- cerrada plants have very narrow lobate quently, I have compared material of all leaves, but the achenes are identical with species recorded with type specimens. those of the much more typical 90/12. Two chromosome counts have been reported There are almost no Taraxacum in in this species, 2n = 32 and 2n = 48 (RI- Madrid. In two days, I found three plants, CHARDS, 1973). It is possible that future all in deep shade in the Retiro Park, where work will reveal the presence of more than they are certainly introduced. Two agamo- one taxon in the Madrid región. species were involved, but neither could be identified with certainty. However, the Sierras above 1000 m are rather rich in Taraxacum sect. Erythrocarpa Hand- native Taraxacum, where they are mostly Mazz. restricted to very wet (in late May) acidic ground. Only T. obovatum, T. marginellum T. malato-belizii V. SOEST (1970) and T. dubium occur on limestone, and MADRID: Puerto de Navacerrada, wet acidic grass- here always in deep shade. land, 1500 m, 21-V-1990, A. J. Richards 90/27,32 (MA Altogether I found 18 species, eight clas- 505716). SEGOVIA: Riofrío de Riaza, hayedo de la Pe- drosa, acidic wet ground near tree-line, 1600 m, 22-V- sified in section Erythrosperma and five in 1990, A. J. Richards 90/17 (MA 505728). section Céltica. The remaining five species are classified within four sections, rather a Originally described from Portuguese high sectional diversity. Two new taxa are mountains. The type only has a single frag- described, T. nietoi (Céltica) and T. navace- mentary achene, which however matches rradense (Alpestria). those of collected material well. The leaves In the Sierras I found only one specimen bear a marked resemblance to those of of an adventive species, classified within T. duplidentifrons Dahlst. This seems to be the largely anthropogenous section Rudera- the first record for Spain. A. J. RICHARDS: TARAXACUM OF GUADARRAMA 203 Taraxacum sect. Erythrosperma (H. Lindb, had already recorded this species from cen- fil.) Dahlst. tral Spain. T. lacistophyllum (Dahlst.) Raunk. T. dubium V. SOEST (1970) MADRID: Puerto de Navafría, acidic grassland in MADRID: Valle de Lozoya, Alameda del Valle, woo- forest gap, 1500m, 23-V-1990, A. J. Richards 90/9 (MA ded spring on limestone, 1250 m, 23-V-1990, A. J. 505734). Puerto de Somosierra, drier parts of steep aci- Richards 90/2 (MA 505741). dic meadows, 1600 m, 22-V-1990, A. J. Richards 90/22 (MA 505723). SEGOVIA: 1 km west of Casia, rocky This species, which is widespread and limestone ground, 1000 m, 22-V-1990, A. J. Richards 90/ common through much of western Europe, 14 (MA 505730). was recorded frora Spain several times by V. Soest. Closely allied to T. braun-blanquettü, with which it grows on the Navafría. Differs T. gallecicum V. SOEST (1954b) chiefly by not being heterophyllous, and by the distinctive end-lobe, best described as MADRID: Puerto de Navacerrada, wet acidic places, 1500 m, 21-V-1990, A. 1. Richards 90/30 (MA 505718). 'hamate-trilobate'. A good match with the SEGOVIA: Riofrío de Riaza, hayedo de la Pedrosa, acidic rather fragmentary type, except for the wet ground near tree-line, 1600 m, 22-V-1990, A. J. achenes which agree with V. Soest's des- Richards 90/15 (MA 505729). cription, but are slightly smaller than those In both localities growing in company of the type. Described from Portuguese with T. malato-belizii, which has less dis- mountains; this seems to be the first record sected leaves. The involucre is very similar for Spain. to that of T. lacistophyllum, but the leaf- shape is quite different, and the small turbi- T. marginellum H. LINDBERG fil. (1932) nate, almost smooth achenes agree well MADRID: Puerto de Navafría, acidic grassland, with those of the type. These are the fírst 1700 m, 23-V-1990, A. J. Richards 90/8 (MA 505735). records for central Spain. SEGOVIA: 1 km west of Casia, rocky limestone meadow, 1000 m, 22-V-1990, A. J. Richards 90/13 (MA 505731). T. catalanum V. SOEST (1954a) As Lindberg noted, best diagnosed by the MADRID: Puerto de Somosierra, drier parts of steep ciliate, white-bordered erect ovate bracts, acidic slopes, 1500 m, 22-V-1990, A. J. Richards 90/23 and by the rather obtuse lateral leaf-lobes; (MA 505722). the leaves are a bright green. Closely allied to T. miniatum, but with a different leaf- The rather broad, green-bordered exte- shape and colour, shorter bracts and shorter rior bracts, the bright green leaves with has- achenes, the rostrum being only 4 mm. tate terminal lobes and concavely notched Lindberg's figure is of the type, which is lateral lobes, and the rather robust achenes untypically robust with late-season dissect- with long spines are diagnostic. ed leaves. The achenes of my material have narrower cones than those of the type. T. braun-blanquettü V. SOEST (1954C) MADRID: Valle de Lozoya, 2 km west of Lozoya, T.