First records of Melilotus albus Medik . ( Fabaceae , Faboideae ) in Santa Catarina , southern Brazil

Melilotus albus Medik. is a cosmopolite and invasive species, native to the Old World, which in Brazil had its occurrence hitherto recorded only in the states of São Paulo, Paraná and Rio Grande do Sul. This study extends its distribution to Santa Catarina state, southern Brazil, due to the recent discovery of populations in the municipalities of Florianópolis and Xanxerê. These new records are ca. 250 km distant from the nearest records, in Paraná state, also in southern Brazil.

The legume family, Fabaceae, is the third largest family of angiosperms, including ca. 730 genera and over 19400 species spread worldwide (Wojciechowski et al. 2004).This family has an immense ecological and also agricultural importance as nitrogen fixers (Soltis et al. 1995;Crews 1999;Yan et al. 2000;Mafongoya et al. 2004;Bromfield et al. 2010) and is second only to Poaceae in agricultural and economic importance (Wojciechowski et al. 2004).Within the subfamily Faboideae tribe Trifolieae, the subtribe Trigonellinae includes three closely allied genera, Medicago L., Melilotus (L.) Mill., and Trigonella L. (Steele and Wojciechowski 2003;Steele et al. 2010).
Melilotus includes 20-25 species native to Eurasia and North Africa (the Palearctic) (Rogers et al. 2008;Özbek et al. 2014), but many species have been introduced to and are now naturalised in various temperate and subtropical regions worldwide (Halvorson and Guertin 2003;Hussey et al. 2007), mainly because of its agricultural uses as forage crops and soil builders (Stevenson 1969;Rogers et al. 2008;Özbek et al. 2014).Some of these species are considered invasive, and have been accounted for negative environmental impacts (Wolf et al. 2003(Wolf et al. , 2004)).
Melilotus albus Medik. is one of the two Melilotus species that occur in Brazil (the other is M. indicus (L.) All.), and was hitherto only recorded in the Brazilian states of São Paulo, Paraná and Rio Grande do Sul ( de Lima et al. 2010de Lima et al. , 2014)).However, during recent (September 2011) collection efforts on Santa Catarina Island, in the municipality of Florianópolis, eastern Santa Catarina state (SC), southern Brazil, we found a population of about 50 adult plants, and a great many of seedlings, in a landfill in the locality of Saco dos Limões (Figures 1 and 2).Three months later, we discovered another population in the municipality of Xanxerê, western SC.These are the first records of M. albus in SC (Figure 3), which are ca.250 km distant from the nearest locality recorded, in Curitiba, Paraná state, southern Brazil.In addition to the fieldwork, we also revised the entire collections of Melilotus at EFC, FLOR, FURB, HBR, MBM and UPCB (acronyms according to Thiers 2014; Appendix 1).
Melilotus albus are biennial or annual herbs, the stem 0.3-2.6 m high, upright or ascending, coarse or fine, grooved or channelled, usually pubescent or pilose near the tip; leaflets of the lower leaves broadly ovate, obovate or rhomboidal, rounded or truncate at the tip, irregularly dentate, 1.5-5 cm long; those of the upper leaves oblonglanceolate, usually rounded or truncate at the tip, dentate or almost entire; stipules 7-10 mm long, entire, narrowly cuneate, those of the lower leaves with one or two teeth near the broadened base; raceme 40-80, rarely 120 flowered, elongated at maturity, 8-15 cm long or occasionally up to 28 cm in some annual varieties; pedicels 1.5-2 mm long; flowers white, 4-6 mm long; calyx 2-2.5 mm long, teeth as long as the tube, rarely shorter, triangular-lanceolate;

NOTES ON GEOGRAPHIC DISTRIBUTION
wings and standard more or less equal and longer than the keel; pod 3-4 mm long, 2-2.5 mm broad, 1.5-2 mm thick, obliquely ovate, reticulately nerved, black, dark grey or tawny, tip obtuse, base of style persisting; seed oval, 2-2.5 mm long, 1.5 mm broad, yellow or rarely greenish-yellow; radicle about half as long as the cotyledons (Stevenson 1969).
Originally native to Eurasia and northern Africa (Halvorson and Guertin 2003), Melilotus albus is now introduced and naturalised to temperate and subtropical areas in the Americas (Halvorson and Guertin 2003) and Australasia (Hussey et al. 2007).This species is adapted to a wide range of conditions, being drought and cold tolerant, although it does not tolerate shade or flooding (Halvorson and Guertin 2003).In Brazil it is ruderal in open and well-drained areas, mainly in farmland, gardens and wastelands.Its conservation status, according to the IUCN criteria (IUCN 2012(IUCN , 2014)), is Least Concern (LC).Because of the invasiveness potential of this species, it is very important the continuous monitoring of its geographical distribution and of the ecological dynamics of its populations in areas where it is not native.

ACKNOWLEDGMENTS
Thanks are due to herbarium MBM for providing support and accommodation for GH and JPRF during their herbarium revisions in Curitiba, Brazil.GH thanks CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior) for the scholarship granted through the "Ciência sem Fronteiras" program.

Figure 1 .
Figure 1.One of the populations of Melilotus albus discovered in a landfill in Saco dos Limões, Florianópolis, southern Brazil.

Figure 3 .
Figure 3. Location of the new records of Melilotus albus in Santa Catarina state, southern Brazil.