STUDIES IN BACCHARIDINAE (ASTERACEAE: ASTEREAE). I: LANUGOTHAMNUS A NEW GENUS FROM SOUTH AMERICAI

It is described a new genus of Asteraceae, named Lanugothamnus, to include eighteen species and one subespecies of Baccharis before placed in the subgenus Tarchonanthoides. The genus Lanugothamnus has discussed its infragenerical treatment, being segregated in four subgenera: Lanugothamnus, Toxicothamnus, Curitybenses, and Tarchonanthoides. The subgenus Toxicothamnus is a taxonomic novelty, while the subgenera Curitybenses and Tarchonanthoides are based in Baccharis sect. Curitybenses, and Baccharis subg. Tarchonanthoides, respectively. Two new sections are described: Sericicarpa and Pluricephala. The former belongs to subgenus Lanugothamnus, while the later belongs to subgenus Toxicothamnus. Furthermore, two new species, named Lanugothamnus Anabelae and L. pluricapitulatus are described, illustrated and have their taxonomic affinities discussed. Lectotypes are proposed to names Baccharis artemisioides, B. patens, and B. squarrosa. Baccharis multipaniculata is placed in synonymy with Lanugothamnus scabrifolius. A key to segregate the subgenera and species of Lanugothamnus is given, and the appropriate new combinations are made.


Pseudobaccharis
Cabrera, Stephananthus Lehm., and the informal groups "Lanugobaccharis" and "B accharis boli viensis" encompassing nine genera in Baccharidinae (Hellwig, 1996).Nesom (1994) included Pingraea and Neomolina in Baccharis, and more recently the author recognized the fragility of the Hellwig's segregation by reduced number of species investigated and also because Hellwig has not provided a complete review of the groups and species, furthermore according with the Zanowiak's cpDNA study evidenced a broad1y defined and largely undivided Baccharis (Nesom 2000).Deble et alo(2004) described the new genus Heterothalamulopsis from Brazil to place Heterothalamus Wagenitzii.Müller (2006) recognized only the genus Baccharis for South America.Baccharis sensu lato according to Müller (2006) comprises four subgenera, and three groups not attributed to a subgenus.The traditional segregated genus Heterothalamus, and also• the probably related Heterothalamulopsis were included without an obvious reason under the subgenus Molina (Müller, 2006: 217-218).Recently, Giuliano & Freire (2011) have accepted the criteria ofMüller and proposed several new sections and new status under Baccharis, mainly of them to include Müller's informal groups.
Until this moment the Baccharidinae are not completely revised and the classical works of Heering (1915) and Malagarriga (1977) comprehend the most important references to knowledge of species of Baccharidinae.Baccharis Linnaeus (1763: 860) is taxonornically poor defIned, and until recently the dioecy was considered crucial to distinguish Baccharis from the other genera of the subtribe Baccharidinae.Baccharis in its narrow sense includes only 120 species (Müller, 2006) or more than 200 species (Hellwig, 1996) and can be characterized by tufted indumentum, staminate flowers with style nearly capitate, composed by distinct longer median sweeping trichomes, pistillate flowers at the apex 5dentate, pistillate flowers with deciduous pappus, and terete, glabrous, 8-20 ribbed cypselae.
The species here treated are currently recognized into Baccharis subg.Tarchonanthoides, but this group of species has the following crucial attributes: absence of tufted indumentum, pistillate and starninate corolla at the apex papillose lobes, pubescent cypsela and style of starninate flowers with branches covered by abundant sweeping trichomes of equallength.

RESULTS AND DISCUSSIONS
The most important morphologic features of Baccharidinae are commented, and sub sequently a new genus, named Lanugothamnus is described, illustrated and also have its infragenerical treatment discussed.For the comments of the genera was adopted the generical treatment of Hellwig (1996), except by Psila that is treated as segregated of Stephananthus, and Neomolina that is recognized under Baccharidiopsis.The species of Baccharis that will be transferred for Lanugothamnus are treated under Lanugothamnus.

Growth habit
Species of Baccharis are frequently subshrubs or shrubs, sometimes with xylopodium.Archibaccharis and Pingraea include many species of woody vines.In Baccharidiopsis some species are weakly woody.Lanugothamnus lychnophorus is a small tree with up to 6 m high, and B. longiattenuata is a tree with up to 15 m high.On the other hand, Stephananthus junceus has herbaceous habit and flexible stems, and Psila caespitosa is a rhizomatous herb, with less than 3 em high.

Foliage
Leave size and shape show great variability in Baccharidinae.The majority of species of Baccharis have medium-sized leaves with chartaceous, pinnately veined or 3-veined blades.Baccharis notosergila displays linear and deciduous leaves and Baccharis multifolia has very smalI, and oblong linear leaves, while B. polyphylla has sulcate leaves.Species of Pingraea show large and dentate or serrate leaves; on the other hand some species of Pingraea have winged stems and leaves reduced to smalI triangular scales.Archibaccharis frequently displays medium-sized leaves, with thin pinnately veined blades.In Heterothalamus the leaves are glutinous and often crowed at the apex of the branches.

Indumentum
Perhaps alI species of Baccharidinae have vestiture, and species recognized as glabrous or punctate glandular, indeed have some type of indumentum, and in these case obscured by a resin layer.The presence of tufted indumentum is considered highly important into recognize the Baccharidinae, though in several groups of Baccharidinae the tufted indumentum are absent, e. g., Archibaccharis and Lanugothamnus.The twin-trichomes are absent in Baccharis and Baccharidiopsis, but are very common in Archibaccharis, Pingraea, and especially in the new genus Lanugothamnus.
The trichomes of Baccharidinae were investigated by Barroso (1976), Hellwig (1992Hellwig ( , 1993)), and more recently by Müller (2006).The scheme here proposed is based in these authors, and also Nesom (1994).In some case new names are adopted to types of trichomes undescribed before.
Trichomes uniseriate: (A) Flagellate trichomes, with subterrninal celI ilistinctly larger than the more basal cells, and the terminal cell is much longer and narrower than alI other cells, and is usually thin-walIed.The tufted trichomes are exclusively found in Baccharidinae, but in several groups are completely absent.

Capitula
The capitula in almost alI species of Baccharidinae are discoid, radiate capitula are found only in functionally staminate capitula of species of Heterothalamus and Baccharis dubia.
Capitulum sex: The distribution of capitula sexes was considered crucial to distinguish the genera of Baccharinae in the past.Actually is considered as a secondary attribute (Nesom 1988a, Nesom 1988b, Müller 2006) the range vary but at a narrower range than the pistillate capitula.The variation pistillate/ staminate ratio per capitulum is not related with generical relationships as proposed by Hellwig (1993Hellwig ( , 1996)); despite in several species of Pingraea may be a tendency to pistillate/ staminate ratio per capitulum of three or more.

Involucrum
Involucrum shape varies from narrowly cylindrical or turbinate to hemispheric.Pistillate involucres are often relatively narrower than staminate involucres of the same species.Species of Baccharis have involucres cylindrical to campanulate, but in Baccharis reticularioides the pistillate involucre is urceolate, while in B. salzmanii and in several other Brazilian species is turbinate.In Heterothalamus rupestris the staminate involucre is campanulate and the pistillate involucre is nearly globose.Pistillate and staminate involucres of about equal size and shape are found in some species of Baccharis, e. g., Baccharis pampeana, and also in Lanugothamnus curitybensis and L. chionolaenoides.

Phyllaries
The phyllaries are imbricate and helically arranged in 2-14 series.Pistillate involucres are often with more phyllaries series than the staminate involucres of the same species.
General coloration of the phyllaries: Typically the phyllaries are greenish-brown colored, with a mediaI brown strip.Stephananthus junceus, some species of Baccharidiopsis, and species of Lanugothamnus have apically purplish phyllaries.
Margin of the phyllaries: The margin of the phyllaries can be entire, scariose, fimbriate or dentate, sometimes with biseriate trichomes associated.

Dorsum of the phyllaries:
The dorsum of the phyllaries is typically more thickened than the margin, and often displays glandular trichomes and/or filiform trichomes.In Baccharis phylicoides the outermost phyllaries are clothed by filiform trichomes with terminal cell rigid, with thickened wall, Lanugothamnus artemisioides have phyllaries with long filiform trichomes, while in the majority of species of Baccharis the dorsum of the phyllaries are glutinous by presence of glandular trichomes.
Venation ofthe phyllaries: The majority of Baccharidinae have a central vein, but some species display parallel veins or pinnately branched vein.

Receptacle
In many species the receptacle is convex or conical, most rarely flat.The point of insertion of the flowers is often well-marked, and commonly presents fimbrils or trichomes.
Receptacular Fimbrils: In several species of Baccharis and Baccharidiopsis in the point of intersection of the flowers and the receptacle, occurs a rather prolonged receptacular honeycomb tooth.
Indumentum of the receptacle: Whitish filiform trichomes are often in Lanugothamnus, uniseriate trichomes with clavate terminal cell occur in Heterothalamulopsis Wagenitzii, while in species of Baccharis the receptacle is glabrous or with uniseriate or biseriate trichomes, very rare glandular trichomes (fide Müller 2006: 48).

Flowers
The shape of flowers of Baccharidinae is applicable to distinguish genera and groups.Staminate flowers are often relatively homogeneous than pistilIate flowers, but exception can be found, e.g., Lanugothamnus montevidensis, and in several species of Baccharidiopsis.
Shape of flowers: The pistillate flowers of Baccharidinae can be filiform or tubular, apically truncated, ligulate or 5-dentate, and usually with less than 10 mm longo Baccharis is characterized by tubular at the apex 5-dentate corolla, Pingraea and Baccharidiopsis, in its tum, included species with tubular at the apex truncate corolla.Ligulate corolla are found in some species of Pingraea, almost alI species of Archibaccharis, Baccharis dubia group, Baccharis boliviensis, alI species of Heterothalamus and Heterothalamulopsis Wagenitzii.In Lanugothamnus and Baccharis thymifolia the pistillate corolla shows papillae apicalIy; furthermore species of Lanugothamnus, e.g., Lanugothamnus ochraceus, have a tendency to produce short and thickened pistillate corolla (Figure 2J-0).The staminate flower consists of a long, cylindric tube and a limb that is divided in five teeth or lobes.The species of Baccharis have lanceolate or oblonglanceolate lobes; while in alI species of Heterothalamus and Lanugothamnus montevidensis the corolla has more or less triangular, short, and erect teeth.
Discolour flowers: The flowers of almost alI species of Baccharidinae display corolIa not discolorous, and often are strarnineous, whitecream or greenish-cream colored, and apically pink or purplish.Exception is found in Heterothalamus that have pistillate flowers with corolla greenishyellow in pistillate capitula and pistillate flowers (often neutral) yelIow or golden-yelIow in functionally starninate capitula.

Corolla trichomes:
Baccharis displays pistilIate corolIa with scattered biseriate trichomes and staminate corolIa with trichomes concentrated in the apex of the tube.In several species of Pingraea the pistilIate corolIa is crowed by uniseriate trichomes apicalIy.
Corolla papillae: Papillae are exclusively found in corolla of pistillate and starninate flowers of all species of Lanugothamnus, and Baccharis thymifolia.The papillae are distributed apically, on dorsal surface of the lobes.

Style
The styles of pistillate flowers are rather homogeneous in Baccharis, being mostly lanceolate or linear-Ianceolate branches, but exceptions occur, e.g., style with deltate branches is found in Baccharis crassipappa and B. myricifolia.In Heterothalamus the style branches are distinctly short, while in some species of Lanugothamnus it is deltate, and in Baccharis dubia and B. macrophylla the style branches are deltate or ovate and slightly asymmetrical, and finalIy in Baccharis thymifolia the style branches is nearly obovate (Figure 2S-U).The style offunctionally starninate flowers are heterogeneous and since Heering (1904) has been used to distinguish groups in Baccharidinae.
HelIwig (1990) provided clifferences, including the length and abundance of sweeping trichomes and branches shape.
. Distribution of stigmatic area: The styles of pistillate flowers have the stigmatic lines along the margins.In the style of functionalIy starninate flowers the stigmatic area are absent.Distribution of sweeping trichomes and shape of style branches: Sweeping trichomes are exclusively found in style of functiona1ly staminate flowers and can be interpreted as crucial to distinguish genera, e.g., alI species of Baccharis display nearly capitate and attached (sometimes partialIy free apicalIy) style branches, and median sweeping trichomes distinctly longer than the basal and terminal ones.Pingraea and Baccharidiopsis have lanceolate style branches and sweeping trichomes of about equal length, often concentrated distally, while in Lanugothamnus the sweeping trichomes are of about equallength and abundant in the whole extension (Figure 2 P-R).

Stamens
The stamens are typical of the majority groups of Astereae, and the anthers are oblong or nearly rectangular, apicalIy nearly triangular, and basalIy rounded or rarely slightly acute, e.g., Baccharis dubia.
Pollen morphology: The polIen grains are tricolporate and spinose (Aster type) with few variations within genera.

Cypsela
The cypselae in Baccharis are shorter than 3 mm, in Pingraea and Heterothalamus often shorter than 1 mm, on the other hand in Baccharidiopsis are usualIy 3-10 mm long, and the apical portion is visible in the capitulum at maturity (Figure lO-V 2A-E).
Pappus bristles: Almost alI species of Baccharidinae have pappus composed by scabrid bristles, and the pappus of pistillate flowers is narrower when compared with the pappus of starninate flowers of the same species.The species of Heterothalamus have pappus rigid and resembles the shape of the pappus of several genera of Hintheruberinae.
Pappus scales or setae: Pappus composed by pectinate setae is found only in the pistilIate flowers of Heterothalamulopsis Wagenitzii.This morphologic feature did not mentioned by Deble et aI. (2004) in the protologue of the new genus, but is detailed illustrated and have your importance investigated (Deble, unp. data).
, Fusion ofpappus bristles: Pistillate flowers can show pistillate pappus fused in a basal ring, e.g., Pingraea, Lanugothamnus, but in the majority of the species the pappus is free or partially fused by few cells at base, e.g., species of Baccharis.
Shape of apical pappus cells: In the majority of species of Baccharis the pappus of staminate flowers is plumose or thickened at the apex, and the cells are patent and apically clavate; however all species of Heterothalumus, and several species of Lanugothamnus have pappus of starninate flowers narrowed at the apex.The pappus of pistillate flowers is frequently narrowed at the apex.
Persistence at cypsela maturity: In all species of Baccharis the pappus of pistillate flowers is deciduous at cypsela maturity; on the other hand the genera Pingraea, Lanugothamnus, and Baccharidiopsis have pappus persistent.In some groups the pappus is elongated at cypsela maturity, e.g., several species of Baccharis, all species of Baccharidiopsis, but in Pingraea and in Archibaccharis the pistillate flowers have pappus not elongated at cypsela maturity.

Cypselae dispersion
The anemochory is the most common in Baccharidinae.All species of the group of species with persistent pappus are anemochoric, but also several species of Baccharis the cypselae also have dispersion by anemochory.The unusual zoochory by bird dispersion was observed in Heterothalamus.
Species with relative large cypselae, e.g., many species of Baccharidiopsis the cypselae gerrninates near the mother plant.This characteristic is also reported to some species of Baccharis.It should be noted that in the majority of species the cypselae dispersion was not investigated.style not or exceeding the corolla, apex divided into deltate to lanceolate branches, stigmatic papillae on marginal line; pappus bristles 2seriate (sometimes l-seriate), fused in a basal ring (rarely free), persistent (rarely deciduous), at apex attenuate, not or strongly elongated at cypsela maturity.Cypselae angulated to laterally compressed (rarely terete), 3-11-ribbed, few or densely clothe by twin-trichomes (type L, and M), and often with biseriate trichomes scattered (type H and C).

DESCRIPTIüN üF IANUGOTHAMNUS
Geographic distribution: Lanugothamnus is a South Arnerica genus with 20 species, found in eastern and southeastern Brazil, Uruguay, Paraguay, Bolivia, and center and northern Argentina.The majority species are found in Brazil and Uruguay.
Etymology: From the Latin lanugus meaning lanose and thamnus that mean bushy, and referring to indumentum of the majority species of the genus.

INFRAGENERICAL TREATMENT
The genus Lanugothamnus can be segregated in four subgenera, and two sections, according with the following features: trichomes of receptacle, type of twin-trichomes of cypselae, cypselae shape and ribs, pappus features, habit, leaf morphology, and capitulescence.The infrageneric treatrnent is summarized in the table 1 Lanugothamnus subgenus Toxicothamnus is characterized by racemiform capitulescence, seemingly glabrous with few uniseriate trichomes (typeA) and biseriate trichomes (type I) on receptacle scattered, broad tubular pistillate corolla, and style not or slightly exceeding at the corolla.Giuliano & Freire (2011) included the pistillate pappus 2-seriate and elongated at cypsela maturity as important morphologic feature to distinguish the sections Coridifoliae (now subgenus Toxicothamnus, under Lanugothamnus) and Tarchonanthoides (now subgenus Tarchonanthoides, under Lanugothamnus), but the pappus of L. scabrifolius and the new species L. pluricapitulatus, described in this paper, have bristles l-seriate, not or slightly elongated at cypsela maturity.On the other hand, both subgenera can be easy segregated by habit, pistillate corolla features, and leaf-shape (Table 1).The subgenus encompasses eight species and one subspecies 14 occurring in Brazil, Uruguay, Paraguay, Bolivia, and center and northem Argentina.
Etymology: From the Latin toxicus meaning poisonous and thamnus that mean bushy, and referring to chernical property of some species of the subgenus, e.g., Lanugothamnus artemisioides and L. montevidensis.
Shrubs, pistillate flowers with pappus 1seriate, not elongated (slightly) at cypsela maturity.Two species highly endemic in southern Brazil (one species is subsequently summarized, and a new species is described in the page 16).
Etymology: From the Latin pluri meaning many and cephala that mean capitulum, and referring to number of capitula of the species.

NEWSPECIES
During the review of herbarium specimens and collections of material two undescribed species of Lanugothamnus were discovery and are described below.
Etymology: The new species is named by the number of capitula.
Eponymy: I dedicate this species to Anabela Silveira de Oliveira-Deble, contemporary Brazilian synantherologist, who has worked with the genus Baccharis s.l. for Brazil.
Comments: Lanugothamnus Anabelae belongs to Lanugothamnus subg.Lanugothamnus, being closely related to L. phylicifolius, both species display pistillate flowers with pappus slightly elongated at cypsela maturity and cypselae with short twin-trichomes on ribs concentrate.
Conservation Status: The geographic distribution of Lanugothamnus Anabelae comprises lees than 1,000 km 2 , the individuaIs grow on bogs or bog soils, 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 Lanugothamnus Anabelae in the Endangered category of the IUCN Red List of Endangered plant species according to the following cri teria (lUCN, 2010)

.. filiform trichomes with deciduous terminal cell
Lanugothamnus montevldensls subsp.montevldensls -Leaves slightly discolorous, grayish-green or greenish brown ad.axially,.and grayish-green abaxially, with laxe to dense filiform tnchomes wlth perslstent The terminal cell displays equallength or longer than the all basal cells.(B) Flagellate trichomes with curved terminal cells, and the terminal cell displays equal length or shorter than the all basal cells.(C) Flagellate trichomes with branched or arbuscularly branched terminal cell.(D) Filiform trichome, wi th su bterminal cell distinctly larger than the more basal cells, or sub equal, and terminal cell distinctly longer and flexible, often winding.(E) Uniserite trichomes with tick-walled terminal cell, the terminal cell displays equallength or longer than the all basal cells.(F) Uniseriate trichomes with tick-walled and forked or branched terminal cell.(G) Uniseriate trichomes with oblong terminal cell or clavate (Figure IA-G).Trichomes biseriate: (H) Glandular, with terminal vesicular cell, and oil secretory, with the typically orange or dark lumen.(I) nonglandular, without terminal vesicular cell, and with vitreous lumen (Figure IH, I).Pedestal trichomes: (J) Trichomes with tick-walled cells, composed of several arched epidermal celIs and seemingly multiseriate basalIy and uniseriate in almost alI length, ending in a acute terminal cell (often curved).(K) Biseriate pedestal trichomes with a glandular apex (Figure lI, K).Twin-trichomes: (L) Twin-trichomes with short basal cells, and very longer terminal celIs.(M) Twin-trichomes with short basal cells, median cells more or less longer and terminal cells slight longer than the median cells and frequently divergent apically.In some group of species the twin-trichomes show a basal cell with orange lumen and longer terminal cells (Figure IL, M).Thfted trichomes: A complex of trichomes, composed by uniseriate trichomes (often types A, B, and D) and biseriate trichomes (often type I) with adjoining basal cells (Figure IA, B, D, I).
19. Leaves concolorous, both surfaces greenish brown, olive brown or dark brown, with I~.