A NEW SPECIES OF BACCHARIS ( ASTERACEAE : ASTEREAE ) AND MISCELLANEOUS NOTES TO SECT . DISCOLORES AND RACEMOSAEl

Baccharis floccosa is described, illustrated and have their taxonomic a:ffinities discussed. The new species belongs to section Discolores De. emendo Cuatrec., and can be easy segregated of ali species of this section by a combination ofthe following features: strongly discolorous leaves, pistillate capitula with 7-9 flowers, and corolla of starninate flowers at the apex clothed by filiform trichomes concentrated at the apex of the tube. The new species is related to sympatric species Baccharis nummularia Malme, but differs by its robust habit (1.5-2.5 m vs. 0.3-0.8 m high), attenuate leaves (vs. rounded), and smaller pistillate capitula, with peduncles densely floccose pubescent (vs. peduncles sericeous pubescent). From the allopatric species Baccharis phylicoides Kunth the new species differs by number of pistillate flowers per capitulum (7-9 vS. 13-65), indumentum on abaxial surface of the leaves consisting of a compact and dense layer (vs. loose layer), and corolla of starninate flowers densely clothed by filiform trichomes concentrated at the apex of the tube. Baccharis floccosa displays range of geographical distribution smaller than 1,000km2, being considered endangered species, according with the criteria ofIUCN. Baccharis nummularia is added to section Discolores and a key to segregate the species of the section Discolores is given. Furthermore morphological features to set apart the sections Discolores and Racemosae Ariza are supplied, as well as Baccharis uncinella De. and B. longiattenuata A. S. Oliveira are positioned into the section Racemosae.


INTRODUCTION
During field collections made in Bom Jardim da Serra in southeast of Santa Catarina state, in November of 2004, and São José dos Ausentes in northeast of Rio Grande do Sul state in November of 2005, it was discovery a species of Baccharis in highlands and wet grasslands at elevation of 1,200-1,800 m altitude, seemingly related with Baccharis uncinella DC. and B. nummularia Malme.This taxon was first determined as Baccharis uleana Malag.(Oliveira et aI., 2006;Oliveira-Deble, 2008), and after seven years, with advanced knowledge of this group is confirmed that is an undescribed species belonging to section Discolores De.
Comments: Baccharis floccosa belongs to section Discolores De. emendo Cuatrec., and can be easy segregated of alI species of this section by a combination of the folIowing features: strongly discolorous leaves, pistillate capitula with 7-9 flowers, and corolla of staminate flowers at the apex clothed by filiform trichomes concentrated at the apex of the tube.The abundant uniseriate trichomes are extremely rare in corolIa of staminate flowers of Baccharis.Baccharis itapirocensis A. S. Oliveira & Deble has corolIa of staminate flowers with uniseriate trichomes with rigid terminal celI (Deble & Oliveira-Deble, 2011, p. 27 [Figure 1: N], Figure 2P-Q).However, in the new species the trichomes are most abundant, and the terminal cell is winding, consisting in a floccose indumentum.
From the allopatric species Baccharis phylicoides Kunth the new species differs by number of pistillate flowers per capitulum (7-9 vs. 13-65), leaves on abaxial surface with indumentum consisting of a compact and dense layer (vs.loose layer), and corolIa of staminate flowers densely clothed by filiform trichomes concentrated at the apex of the tube (vs.absent).Baccharis uncinella De. (sect.Racemosae) is superficially similar with the new species, but can be easy segregated by sessile and smalIer leaves, and principalIy by trichomes with branched terminal celI (Figure 2C-F).
Conservation Status: The geographic distribution of Baccharis floccosa comprises lees than 1,000 km 2 , the individuaIs grow on grasslands and wet grasslands, and the populations are few and fragmented; additionally, the high specialized habit, cattle and tourism directly affect the populations.Due to the observed threats, it seems prudent to include Baccharis floccosa in the endangered category of the IUCN Red List of Endangered plant species according to the folIowing criteria (IUCN, 2010) Baccharis uncinella was previously placed in sect.Discolores (Candolle, 1836, p. 415;Cuatrecasas, 1967, p. 87 [sub  The section Discolores was proposed by Candolle (1836, p. 414) to include fourteen species, but the species encompassed are not morphologically related, including two species of Gochnatia and several taxa of the subgenus Tarchonanthoides.Cuatrecasas (1967, p. 87) made an emendavit recognizing Baccharis phylicoides as lectotype.
The section Racemosae was proposed by Ariza Espinar (1973, p. 183) to position Baccharis dracunculifolia.Giuliano (2001, p. 141) placed the section Racemosae in the synonymy ofthe section Discolores De. emendo Cuatrec.most based in capitulescence and leafshape.In a recent contribution, Giuliano & Freire (2011, p. 333)  The presence of uniseriate trichomes with branched or forked terminal cell is diagnostic, and based in this attribute Baccharis uncinella DC. and B. longiattenuata A. S. Oliveira are presently placed in the section Racemosae (Figure 2A-F, R, S).