A synopsis of the fern family Blechnaceae in Santa Catarina, Brazil: reviewing Sehnem’s

: We reviewed the fern family Blechnaceae in Santa Catarina, southern Brazil, in order to update the work done by Sehnem in Flora Ilustrada Catarinense. Ten genera and 21 species in the family have been recognized. In this work, descriptions and identification keys for the species are presented, as well as comments and a comparative list of Sehnem’s nomenclature and the current state-of-the- art in Blechnaceae nomenclature. Resumen Palabras


Introduction
The Blechnaceae family is nested within eupolypods II clade and contains 25 genera and more than 250 species (PPG 1 2016; Molino et al. 2018). Its main characteristics are the sori that borne on a commissural vein parallel to the midvein or costae, and young red fronds (Tryon & Tryon 1982;Gasper et al. 2016). The family is subcosmopolitan and more diversified in Neotropics and Oceania (Dittrich et al., 2007).
In Brazil, the first records of Blechnaceae were made by Fée (1869a, b). In these works, the author describes 17 species of Blechnum L. and eight of Loma-ria Willd. Nowadays, numerous regional works can be referred, e.g., Pietrobom & Rosário (2008), Dittrich et al. (2007Dittrich et al. ( , 2015Dittrich et al. ( , 2018, Salino et al. (2017) and, among them, the 'Flora Ilustrada Catarinense', published by Aloysio Sehnem. In his Blechnaceae treatment, Sehnem (1968) recognized three genera (Blechnum, Salpichlaena, and Stenochlaena) and described 29 taxa. However, one of the species identified by Sehnem (1968) as Stenochlaena erythrodes (Kunze) Underw. is, as a matter of fact, Lomariopsis marginata (Schrad.) Kuhn, a species belonging to the family Lomariopsidaceae -leaving 28 species of Blechnaceae in his treatment (most of which were synonymized or re-circumscribed since 1968). Given nomenclatural updates throughout these 50 years, changes in species circumscription, and a new record for Santa Catarina State, our work aims to review the taxonomic treatment of Blechnaceae for Santa Catarina State, Brazil.

Material and methods
We have consulted specimens from the following herbaria: B, BHCB, B, CRI, FLOR, FURB, HB, HBR, HUEFS, ICN, JOI, K, MB, MO, NYBG, PACA, R, RB, SJRP, SP, UPCB (herbarium abbreviations follow Thiers 2020). The terminology follows Lellinger (2002), with modifi cations. All species descriptions were elaborated based exclusively on examined specimens, and only a selection of them is presented. The synopsis is arranged in alphabetical order and, fi nally, we present a comparison between the nomenclature adopted by Sehnem (1968) and the most updated one.

Study area
The State of Santa Catarina, Brazil, covers an area of ≈96,000 km² and is located within the subtropical Atlantic Forest (Figure 1). The State has three dominant vegetation types (Atlantic rain and cloud forests, Araucaria forest, and semi-deciduous forest) and highland prairies (Oliveira-Filho et al. 2015). The climate type is Cfa and Cfb (Alvares et al. 2013), with average annual precipitation between 1,100-2,900 mm. The altitude ranges from 0 to 1800 m a.s.l.

Results and discussion
We recognized 21 species in 10 genera. The names applied by Sehnem (1968) and recognized here can be seen in Table 1. Comments: Similar to Austroblechnum organense, which has a smaller size and fewer pinnae (vestigial or not) than A. divergens. Dittrich et al. (2017) also mention the scales, which are lustrous in A. organense and opaque in A. divergens.

Austroblechnum lehmannii (Hieron.) Gasper & V.A.O.Dittrich
Rhizomes erect to decumbent; fronds dimorphic; stipes atropurpureous at the base and stramineous towards the apex; sterile blades pinnatisect, gradually reduced towards the apex and base, proximal pinnae reduced to semi-elliptical to semicircular lobes; rachises glabrous or clothed with ovate scales abaxially; sterile pinnae 15-19 pairs, fully adnate to the rachises, patent to slightly ascending, falcate; veins free, usually bifurcate, rarely simple close to the pinnae apices, sometimes 2x-bifurcate only at the pinnae bases, ending before the margin in a clavate apex. Comments: Similar to A. squamipes, from which it differs by its non-stoloniferous rhizome, stipe color (usually stramineous towards the apex), falcate pinnae, and pinnae apices obtuse. Furthermore, this species is found in forest formations whilst A. squamipes is found in grasslands.

Austroblechnum organense (Brade) Gasper & V.A.O.Dittrich
Rhizomes erect to ascending, sometimes forming a thin caudex; fronds dimorphic; stipes usually atropurpureous at the base and stramineous towards the apex; sterile blades pinnatisect, truncate at the base, with 1-3 pairs of vestigial pinnae; rachises glabrous; sterile pinnae 13-14 pairs, fully adnate to the rachises, ensiform; veins free, simple (the distal ones) or commonly bifurcate, ending before the margin in a clavate apex. Comments: A rare species in Santa Catarina State. It is similar to A. divergens, from which it differs by its smaller size and lustrous rhizome scales. This species was not recorded by Sehnem (1968).

Austroblechnum penna-marina (Poir.) Gasper & V.A.O.Dittrich
Rhizomes ascending to short-creeping, stoloniferous; fronds dimorphic; stipes usually atropurpureous, rare stramineous and nigrescent at the base; sterile blades pinnatisect, narrowly obtrullate to oblanceolate, gradually reduced at the apex and base, without vestigial pinnae; rachises glabrous or with brownish scales in both surfaces; sterile pinnae 25-45 pairs, fully adnate to the rachises, patent or the basal ones sometimes slightly reflexed, oblong; veins free, bi-furcate, sometimes simple, ending in a clavate apex before the margin.  -27.9816, -49.33083, A.L.Gasper 2988, 13/11/2011 Comments: In Santa Catarina State the species is recorded in high altitudes, and is commonly found in rocky, open environments. It differs from the other species of the genus by its long-creeping, stoloniferous rhizome, sometimes forming dense populations in grasslands and Araucaria forest fragment edges. Furthermore, the narrower blade width and fertile pinnae longer than sterile distinguishes this species from the others in Austroblechnum.

Austroblechnum squamipes (Hieron.) Gasper & V.A.O.Dittrich
Rhizomes erect to ascending, stoloniferous; fronds dimorphic; stipes atropurpureous throughout or stramineous at the base and atropurpureous towards the apex; sterile blades pinnatisect, narrowly oblanceolate, gradually reduced towards the apex and base; rachises adaxially glabrous, abaxially glabrous or with sparse scales; sterile pinnae 14-18 pairs, fully adnate to the rachises, fully patent or patent in the proximal region and ascendant in medial and distal region, triangular; veins free, bifurcate, ending in a clavate apex before the margin. Comments: see Austroblechnum lehmannii for comparison.

Blechnum austrobrasilianum de la Sota
Rhizomes erect to ascending; fronds monomorphic; stipes atropurpureous at the base, stramineous towards the apex, with narrowly triangular to lanceolate, light brownish to nigrescent scales at the base; blades pinnate at the base, pinnatisect towards the apex, the base truncate, deltoid to lanceolate, with pinnatifid apex, glabrous; rachises with catenate, whitish or brownish hairs abaxially, sometimes with brown scales; pinnae 16-36 pairs, the first pair basiscopically free, acroscopically expanded, slightly adnate, or auriculate; veins free, bifurcate or 2x bifurcate (rarely 3x bifurcate proximally), ending in a clavate apex before the margin. Comments: This species is similar to B. occidentale. Blechnum austrobrasilianum has a chartaceous blade consistency and basal pinnae partially or fully adnate to the rachises on the acroscopic side and free from the rachis on the basiscopic side (in B. occidentale both sides are free). In B. occidentale the basal pinnae are virtually perpendicular to the longitudinal rachis axis, whilst in B. austrobrasilianum the pinnae are parallel to the longitudinal rachis axis, a feature difficult to observe in herbaria. It is also similar to B. laevigatum, however its hairs are restricted to the rachis and rare in other parts of the plant. This species was described only in 1973 by de la Sota, without records for Santa Catarina (de la Sota 1973).

Blechnum gracile Kaulf.
Rhizomes erect to ascending; fronds monomorphic; stipes stramineous throughout or atropurpureous at the base and stramineous towards the apex, with concolorous scales; blades pinnate, ovate or deltoid, at the apex reduced to a conform pinna, glabrous; rachises with linear, brownish scales on both surfaces and catenate brownish hairs adaxially; pinnae 3-4 pairs, partially adnate, narrowly elliptic to linear, the apex acute to cuspidate; veins free, bifurcate or 2x bifurcate, ending in a clavate apex before the margin. Comments: the closest taxon is the hybrid Blechnum × caudatum. Blechnum gracile differs by its smaller size, fewer pinnae pairs (four pairs at most in B. gracile). Also, we can highlight the presence of auricles on the acroscopic side at basal pinnae in B. × caudatum, and the surcurrent and decurrent apical pinnae.

Blechnum laevigatum Cav.
Rhizomes erect to ascending; fronds monomorphic; stipes tan or atropurpureous at the base, stramineous towards the apex, bearing hyaline catenate hairs mainly distally; blades pinnate at the base, pinnatisect towards the apex, lanceolate, hairy, the hairs similar to those found on the stipes; rachises bearing hairs identical to the ones on the stipes and blades; pinnae 17 pairs, patent, fully adnate to the rachises except the basalmost two pinnae pairs (basiscopically excavate), oblong; veins free, 2x bifurcate, ending in a in a clavate apex before/or at the margin.
Comments: The few samples from Santa Catarina State are similar to B. occidentale and B. austrobrasilianum. They differ from both by its hairy stipes, rachises, blades, and veins.

Blechnum polypodioides Raddi
Rhizomes erect to ascending; fronds monomorphic; stipes stramineous, sometimes atropurpureous at the base, usually bearing hyaline, catenate hairs; blades pinnate at the base, pinnatisect towards the apex, elliptic-lanceolate, gradually to abruptly attenuate toward base and apex, glabrous; rachises hairy, bearing hyaline and catenate hairs on both surfaces; pinnae 13-30 pairs, fully adnate to the rachises, abaxially glabrous or bearing hyaline hairs, adaxially bearing similar hairs; veins free, simple or rarely bifurcate, ending in a slightly clavate apex at the margin.

Blechnum × caudatum Cav.
Rhizomes erect; fronds monomorphic; stipes stramineous throughout or atropurpureous at the base; blades pinnate at the base, pinnatisect towards the apex, truncate, deltoid or ovate, abruptly reduced to a conform or subconform terminal pinna, glabrous; rachises glabrous or bearing hyaline, catenate hairs on both surfaces, rarely scaly; pinnae 9-15 pairs, basal pinnae petiolulate with acroscopic auricles overlapping the rachis, the basiscopic side excavate, gradually adnate towards the apex, ensiform to falcate; veins free, usually simple or bifurcate, and then only proximally, ending before the margin in a clavate apex.

Cranfillia mucronata (Fée) V.A.O.Dittrich & Gasper
Rhizomes erect to ascending, bearing nigrescent, lustrous scales at the apex; fronds dimorphic; stipes nigrescent at the base, brownish towards the apex; sterile blades pinnatisect, rarely pinnatifid at the apex, lanceolate, truncate or slightly reduced at the base, glabrous; rachises glabrous or rarely bearing catenate hairs; sterile pinnae 14-23 pairs, some basal and medial pinnae reflexed or patent to slightly ascending, the first pair basiscopically excavate, the remaining pinnae fully adnate to the rachises; veins free, bifurcate or 2x bifurcate, ending in a slightly clavate apex before the margin. Comments: Similar to A. divergens, but differs from it by its nigrescent stipe at the base and brownish towards the apex, no vestigial pinnae, and by having the first pinnae pair basiscopically excavate.

Lomaria spannagelii (Rosenst.) Gasper & V.A.O.Dittrich
Rhizomes erect, forming a stout caudex; fronds dimorphic; stipes stramineous, atropurpureous or stramineous-brownish with an atropurpureous base; sterile blades pinnate about two thirds of the length, then pinnatisect, gradually reduced towards the apex and base, here to auriculiform pinnae; rachises scaly; sterile pinnae 36-53 pairs, fully adnate to the rachises, the abaxial surface bearing brownish, linear scales, the adaxial one glabrous or sometimes like the abaxial surface, albeit also bearing whitish, linear scales; veins free, bifurcate or 2x bifurcate (distally rarely simple), ending before the margin. Comments: The species is notably defined by its heavily sulcate rachises and discolorous surfaces when herborized. It is usually found near watercourses in Araucaria forest.

Lomaridium plumieri (Desv.) C.Presl
Rhizomes long-creeping, bearing denticulate scales; fronds dimorphic; stipes usually atropurpureous at the base and stramineous towards the apex; sterile blades pinnate at the base, pinnatisect towards the apex or pinnatisect throughout, slightly to abruptly reduced at the base, bearing (0) 1-5 pairs of vestigial pinnae, gradually reduced towards the apex to a terminal subconform pinna; rachises glabrous or bearing linear, brownish scales on the adaxial surface, sometimes also bearing hyaline, catenate hairs, abaxially glabrous; sterile pinnae 17-37 pairs, fully adnate to the rachis, sursumcurrent, linear-oblong, glabrous on both surfaces; veins free, bifurcate or not, ending before the margin in a clavate apex.  -26.3225, -49.30916, F.Bittencourt 51, 13/04/2014, FURB. Comments: This species differs from the others in the study region by its long-creeping rhizome and usually scandent habit, becoming fertile only after climbing a tree. Moreover, another dis-tinct feature is the marginally denticulate rhizome scales.

Lomariocycas schomburgkii (Klotzsch) Gasper & A.R.Sm.
Rhizomes erect, forming a stout caudex; fronds dimorphic; stipes usually stramineous with an atropurpureous base, sometime stramineous or brownish throughout; sterile blades pinnate at the basal and medial regions, distally pinnatisect, gradually reduced towards the apex and base (here to auricular projections), sometimes abruptly reduced at the base; rachises scaly on both surfaces; sterile pinnae 20-44 pairs (excluding auriculate pinnae), sessile, medial pinnae gradually adnate towards the apex, margin plane or slightly to strongly revolute; veins free, simple, ending in a clavate apex before the margin, hardly visible.

Parablechnum cordatum (Desv.) Gasper & Salino
Rhizomes erect to ascending, bearing concolorous scales; fronds dimorphic; sterile stipes usually atropurpureous (sometimes nigrescent) at the base or stramineous throughout with atropurpureous spots; sterile blades pinnate, truncate at the base, usually lanceolate, ending in a conform pinna; rachises scaly, the scales linear-lanceolate, brownish; aerophores present or not at pinnae bases, elliptical, discrete; sterile pinnae 6-26 pairs, the basal and medial petiolulate, apical pinnae decurrent, abaxially bearing brownish scales mostly on costae, sometimes in the photosynthetic tissue; veins free, simple or bifurcate, ending before the margin in a clavate apex or not. Comments: This is the only species in the study region that features aerophores. This species has a broad circumscription and distinguishes itself from P. usterianum by its erect rhizome and larger and bigger pinnae. Sehnem (1968) recognized several species of Parablechnum (as Blechnum), however, systematic studies are necessary to better delimit these taxa.

Salpichlaena volubilis (Kaulf.) J.Sm.
Rhizomes long-creeping; fronds monomorphic; stipes stramineous; petiolules similar to the stipes; blades bipinnate, deltoid, truncate or obtuse at the base, gradually reduced towards the apex, ending in a subconform pinna; rachises scandent with indeterminate growth, reaching easily more than 10 meters, bearing brownish, catenate hairs (rarely hyaline) in both surfaces, the scales similar to those on rhizome or absent; veins free, simple or bifurcate, ending before the margin in a collecting vein. Comments: This is the only species of the genus in Santa Catarina State. It can be distinguished by its lianescent habit and indeterminate growth of the fronds.

Telmatoblechnum serrulatum (Rich.) Perrie, D.J.Ohlsen & Brownsey
Rhizomes long-creeping; fronds monomorphic; stipes usually stramineous, rarely atropurpureous at the base; blades pinnate, truncate at the base, reduced at the apex to a conform pinna; rachises usually glabrous on both surfaces, sometimes scaly abaxially; pinnae 20-29 pairs, sessile, articulate to the rachises, the margin plane, rarely revolute, serrate; veins free, bifurcate, rarely 2x bifurcate, ending at the margin. Comments: The species differ from the others in the region by its articulate pinnae.  Sehnem's (1968) proposal. Author names are cited exactly as written in the original work, and we listed only species that Sehnem cited for Santa Catarina State. The names on the left column are not necessarily synonyms of the names on the right column. *: Lomariopsidaceae.