The goal of this paper is to enumerate the pteridophytes that occur in the semi-árid region of the State of Pernambuco, Brazil

AMBROSIO, S. T.

MELO, N. F. de

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éJAmerican Fern [ournal 91(4):227-229 (2001)SHORTER NOTESNew Records of Pteridophytes in the Semi-Arid Region of Brazil.-In Brazil,70% of the Northeast region, including the northern portion of the state ofMinas Gerais, is covered by semi-arid vegetation. The state of Pernambuco, forexample, has a total area of 98,079 km-, of which 60,000 km2 is covered bytypical caatinga vegetation (Egler, Rev. Bras. Geog.13: 65-78. 1951; Sampaio,pp. 35-63 in Bullock and Davidse, Seasonally Dry Tropical Forest, 1995).Since water deficiency appears to be the key factor in limiting the occur-rene e of pteridophytes in seasonally dry tropical areas, there are relatively fewspecies of pteridophytes known from semi-arid regions or caatinga vegetation.Nevertheless, a few species of pteridophytes are well adapted to survival insuch areas (Kornás, pp. 391-395 in Dyer and Page, Biology of Pteridophytes,1985). For Peru, Tryon (Cont. Gray Herb. 194:1-253. 1964), records 176 nativespecies of pteridophytes across four vegetation types, including the xeric Si-erra Steppe and Scrub vegetation. Also many members of the Pteridaceae, Tri-bo Cheilantheae, have been found in the xeric and semixeric regions of centraland northeastern Mexico (Tryon & Tryon, 1982, Ferns and allied platiis, withspecial reference to tropical America). Other works refer to the occurrence ofpteridophytes in the dry environments of Africa (Kornás, Acta Soe. Poloniae46:669-690. 1977), and in Australia the genus Cheilanthes is noted for itsability to survive in low humidity conditions (Quirk & Chambers, Fern Gaz.12:121-127. 1981). In Brazil, Barros et aI. (Biol. Bras.l: 143-159. 1989) havedocumented nine species of pteridophytes in the caatinga vegetation of Per-nambuco.The goal of this paper is to enumerate the pteridophytes that occur in thesemi-arid region of the State of Pernambuco, Brazil, document three new re-cords, and add information about the habitat preferences of these plants.Pteridophytes were collected in Petrolina (90009'S, 40022'W), which is sit-uated in the semi-arid region of Pernambuco, northeastern Brazil. This area islocated at an altitude of 365 m in a region known as the Sertaneja Depression.The climate is characterized by extended dry periods alternating with ephem-eral rains. The region corresponds to type BSwh, of Kõppen's system (Embra-pa, 1993. Zoneamento Agroecológico do Nordeste) and the annual rainfall is510 mm. The vegetation is xerophytic, with Bromeliaceae and Cactaceae beingespecially representative (Egler, Rev. Bras. Geog.13:65-78. 1951)Species identifications were carried out using Alston et aI. (Bull. Brit. Mus.Nat Hist. 9:233-330. 1981), Proctor (Bull. Brit. Mus. Nat Hist. 7:3-5. 1985),Mickel & Beitel (Mem. New York Bot. Garden 46:1-568. 1988), and Tryon &Stolze (Fieldiana Bot. 29:1-80. 1992). Voucher specimens are deposited inTSAH, the herbarium of the Tropical Semi-Arid Agricultural Research Cen-ter-Embrapa (Brazil).Acrostichum danaeifolium Langsd. & Fisch. [Ambrósio 55, TSAH 1728228 AMERlCANFERN]OURNAL:VOLUME91 NUMBER4 (2001)&1729], Thelypteris interrupta (Willd.) lwatsuki [Ambrósio s.n., TSAH 1721],and Marsilea quadrifolia L. [Ambrósio 52, TSAH 1723] are recorded for thefirst time in the Brazilian serni-arid region. Thelypteris interrupta and A. dan-aeifolium were found to be common in humid soils of the caatinga, near irri-gation channels. These species probably colonized the region naturally withthe advent of modified habitats as niches became available for their survival.Tryon (Cont. Gray Herb.194:1-253.1964) observed that, in Peru, non-nativespecies have become naturalized along irrigation channels or in areas thatbecome more mesic as a result of their presence. Marsilea quadrifolia occursin aquatic environments, such as rivers and streams and, according to Allsopp(Nature 169:79-80.1952), members of the genus are probably able to survivedrought conditions due to their desiccation resistant sporocarps. Kornás (inDyer and Page, Biology of Pteridophytes, 1985) also comments upon the oc-currence of pteridophytes in areas where the climate is extremely dry, as indeserts or sub-desert regions of tropical Africa. Thelypteris and Marsilea areamong the genera that have been found there.Anemia tomentosa (Sav.) Sw. var. tomentosa [Ambrósio 54, TSAH 1724],Pityrogramma calomelanos (1.) Link. var. calomelanos [Ambrósio 51, TSAH1725], Selaginella convoluta (Arn.) Spring [Ambrósio 53, TSAH 1722], S. sel-lowi Hieron. [Ambrósio s.n., TSAH 1726], and Azolla microphylla Kaulf [Arn-brósio 61, TSAH 1727 & 1730] were also collected from Petrolina. These spe-cies have previously been reported from other serni-arid regions of Brazil (Bar-ros et 01., Biol. Bras. 1:143-159.1989). ln their floristic survey, Barros et al. alsoreported Anemia villosa Humb. & Bonpl. Ex Willd., Anemia oblongifolia (Cav.)Sw., Hemionitis tomentosa (Lam.) Raddi., Polypodium polypodioides (1.)Watt., and P hirsutissimum Raddi. as part of the vegetation of the caatinga.The most notable pteridophyte of the semi-arid region is certainly S. convo-luta, the poikilohydrous type, also observed by Morelo (Rev.Bras. Biol. 14:83-108. 1954). This reviviscent species has physiological characters that conferresistance to hydric stress; they curl up and remain alive through the drought,unfolding each time they are moistened (Rawistscher et al., An. Acad. Bras.Ciên. 21: 287-301. 1952). Although pteridophytes are uncommon in xeric en-vironments, especially when compared to areas with more mesic edafoclimaticconditions (Ambrósio and Barros, Acta Bot. Bras. 11:105-113. 1997), they arebecoming increasingly documented and studied (Kornás, Acta Soc. Poloniae46:669-690. 1977, and other references above). The three new records dis-cussed above are intended to show that the distribution of pteridophytes inxeric regions remains still largely undocumented.The authors are grateful to the Tropical Semi-Arid Agricultural ResearchCenter-Embrapa / Petrolina-PE for the use of its premises and equipment,Dr. Alexandre Salino, Federal University of Minas Gerais, for his suggestions,Dra Leonor Costa Maia, Federal University of Pernambuco, for reviewing themanuscript, and CNPq (Conselho Nacional de Desenvolvimento Científico eTecnológico) for financial support.-- SANDRAT. AMBRÓSIO,Center for Biolog-ical Sciences, Federal University of Pernambuco, Recife-PE, and NATONIELF.DEMELO,Center for Biological Sciences, Federal University of Pernambuco,SHORTER NOTES 229Recife-PE and Tropical Semi-Arid Agricultural Research Center-Embrapa,Petrolina-PE.

New records of Pteridophytes in the semi-arid region of Brazil.

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New records of Pteridophytes in the semi-arid region of Brazil.

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