Chromosome Studies of Brazilian Ferns

Alice F. Tryon Hortensia P. Bautista Izonete da Silva Araújo About the authors

Abstract

Chromosome numbers, habitat and general geographic distributions are reported for a sample of ferns from the vicinity of Manaus. These numbers are compared with those reported for species in other regions. The report of n=ca. 154 for Schizaea incurvata is the first record of the genus in the American tropics and the others are first counts of these species in continental South America. In Lindsaea n=42 and n=ca. 84, are somewhat lower and appear to represent a line distinct from the species of the paleotropics with n=47. In Trichomanes n=32, 64 and 128 appear to be levels of polyploidy based on X=8, while n = 72 is possibly based on X=9 and suggest possible diverse lines in the genus. Pityrogramma calomelanos with n=116 is considered as an octoploid based on X=29. Our sample covering about ten percent of the pteridophytes in the area we collected, yielded numbers ranging between n=32 and n=154, and generally appears to represent high polyploid levels.

Resumo

São apresentados números de cromossomos, habitats e distribuição geral de 11 espécies (4 gêneros) de pteridófitas da região de Manaus. Estas são as primeiras contagens cromossômicas destas espécies na América do Sul. São feitas comparações com números referidos para estes gêneros em outras regiões geográficas. Os números variam entre n=32 e n=154 e parecem representar altos níveis de poliploidia.

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Publication Dates

  • Publication in this collection
    Apr 1975
Instituto Nacional de Pesquisas da Amazônia Av. André Araujo, 2936 Aleixo, 69060-001 Manaus AM Brasil, Tel.: +55 92 3643-3030, Fax: +55 92 643-3223 - Manaus - AM - Brazil
E-mail: acta@inpa.gov.br