Bot. Macaronésica 24: 73-85 (2003) 73 CORRELATIONS BETWEEN MORPHOLOGICAL-ANATOMICAL LEAF CHARACTERISTICS AND ENVIRONMENTAL TRAITS IN SOUTHWEST AFRICAN SPECIES OF ANDROCYMBIUM (COLCHICACEAE) N. MEMBRIVES 1 , J. PEDROLA-MONFORT 1 & J. CAUJAPÉ-CASTELLS 2 1 Estació Internacional de Biologia Mediterrània-Jardí Botànic Marimurtra. Passeig Karl Faust, 10. 17300 Blanes. Girona. Apdo. Correos 112. Spain. e-mail: (nuriamem@jazzfree.com and jpedrola@grn.es) 2 Jardín Botánico Canario Viera y Clavijo. Apdo 14 de Tafira Alta. 35017. Las Palmas de Gran Canaria. Spain. e-mail: (julicaujape@granca.step.es) Recibido: noviembre 2000 Palabras clave: Androcymbium, Colchicaceae, Sudáfrica, morfología, anatomía, aspectos ambientales, correlaciones. Key words: Androcymbium, Colchicaceae, South Africa, morphology, anatomy, environmental traits, correlations. SUMMARY We studied 32 populations belonging to 17 Southwestern African taxa of the genus Androcymbium in order to explore the relationships between leaf morphological and anatomical variation and environ- mental characteristics as measured by distribution in two different type velds (Fynbos and Karoo-Karoid types) and the values of 16 edaphic parameters from 22 soil samples. Our results show that only hydric disponibility (measured as the amount and distribution of annual rainfall, and the water retention capa- city) correlates significantly with morphological leaf characteristics in Androcymbium. We detected no significant correlations between pairwise combinations of anatomical traits and climatic or edaphic parameters. These results conform to the hypothesis that the diversification of Southwestern African species of Androcymbium, has been mainly influenced by the arid gradient that already existed when these species began to diversify in the Late Miocene. Thus, they seem to agree with the hypothesis of Stebbins that predicts relatively rapid plant evolution in arid to semiarid regions. Because solely some combinations between characteristics related to aridity and morphological traits are significantly corre- lated, our results reflect only partially Axelrod and Raven's suggestion that the specific diversity in South Africa is a consequence of climatic and edaphic fragmentation. RESUMEN Se estudiaron 32 poblaciones pertenecientes a 17 taxones del género Androcymbium distribuidas en Sudáfrica Occidental con el objetivo de explorar las relaciones entre características morfológicas y anatómicas foliares y características ambientales medidas según la distribución en dos tipos de vege- ISSN 0211-7150