Fern flora of Viçosa, Minas Gerais State, Brazil: Dennstaedtiaceae, Lindsaeaceae and Saccolomataceae

ABSTRACT As part of an ongoing project treating the ferns and lycophytes from the region of Viçosa, Minas Gerais State, Brazil, we here present the taxonomic treatment of the early divergent lineages of the leptosporangiate ferns: the families Dennstaedtiaceae, Lindsaeaceae and Saccolomataceae. We have been sampling the remnant forest patches since 2012; we also fully reviewed the collection of herbarium VIC and other online collections: F, IAN, NY, PH, RB, U, UC, UPCB, US, and WTU. In the region of Viçosa, six taxa belonging to those families occur: Dennstaedtia cicutaria and Pteridium esculentum subsp. arachnoideum (Dennstaedtiaceae); Lindsaea lancea var. lancea, L. quadrangularis subsp. quadrangularis, and L. stricta var. stricta (Lindsaeaceae); and Saccoloma elegans (Saccolomataceae). Among these taxa, only L. quadrangularis subsp. quadrangularis and S. elegans are endemic to the Brazilian Atlantic Rainforest; the remaining are widespread in the Neotropics. We present keys, descriptions, illustrations, examined specimens, and comments.


Introduction
At the end of the era in which the plant Classification Systems were mostly based on morphological data, Dennstaedtiaceae was considered a big family, comprehending three subfamilies (or tribes) and about 17 genera (Tryon & Tryon 1982, Kramer 1990. With the advent of molecular data, those subfamilies were raised to family-level, some families were created, and now the earlydiverging leptosporangiate ferns are represented by Cystodiaceae (one genus), Dennstaedtiaceae with a stricter circumscription (11-12 genera), Lindsaeaceae (seven genera), Lonchitidaceae (one genus), Saccolomataceae (one or two genera), as well as the great Pteridaceae (+50 genera) (Smith et al. 2006, PPG I 2016, Shang et al. 2018.
Brazil is represented by Dennstaedtiaceae with eight genera and 26 species, Lindsaeaceae with one genus and 34 spp., Lonchitidaceae with one genus and one sp., and Saccolomataceae with one genus and nine spp., leaving Pteridaceae apart (which is subject to another paper) (Kramer 1957, Pena et al. 2020, Schwartsburd & Pena 2020. In general, these plants present characters considered plesiomorphic that are typical of the early-diverging lineages of Polypodiales, such as solesnotelic rhizomes clothed with hairs or primitive scales, large, highly dissected leaves, the sori that are truly marginal and protected by inner and outer indusia, and trilete spores (Tryon & Tryon 1982, Kramer 1990, PPG I 2016.
Pteridium is spread all across the globe (except for Antarctic) and may be the one most important to mankind by if directly affects the local human populations: it behaves as a pioneer weed invading croplands; it spreads its underground rhizomes making it hard to be removed; it intoxicates the cattle and horses; and it also intoxicates humans, when ingested -some studies also pointed out the transmission of its toxins (the psilatoquinis) via cow milk (e.g., Tryon 1941, Evans 1976, Page 1976, Marrs et al. 2000, Martini-Santos et al. 2010, Oliveira et al. 2018, Schwartsburd et al. 2018 SciELO Preprints -This document is a preprint and its current status is available at: https://doi. org/10.1590/2236-8906-15/2022

Material and methods
In the region of Viçosa, Minas Gerais State, Brazil, the remaining forest patches are classified as Semi-Deciduous Seasonal Forest (IBGE 2012). The local elevation ranges from 600 to 900 m.a.s.l.
We have been sampling the remnant forest patches since 2012. Specimens were collected and dried according to usual methods for fern collections (Windisch 1992) and then incorporated in herbarium VIC (acronyms following Thiers, continuously updated), with duplicates to be sent to other herbaria. We also fully reviewed the collection of herbarium VIC and collections of other herbaria online: F, IAN, NY, PH, RB, U, UC, UPCB, US, and WTU. Although the classification system adopted for the previous fascicles was based on an adaptation of Kenrick & Crane (1997) and Smith et al. (2006), we here adopt the system of PPG I (2016). Morphological terms are according to Lellinger (2002).

Dennstaedtiaceae
Rhizomes generaly long-creeping, solenostelic or rarely dictyostelic or polycyclic, bearing hairs or rarely with primitive scales. Leaves monomorphic; stipes often with epipetiolar buds, usually with a omega-shaped vascular strand; laminae 2-5-pinnate, rarely less dissected; veins free or rarely anastomosing and then without included veinlets; indument formed by hairs or glandular hairs, or absent.
Sori marginal or submarginal, linear or discrete, introrse or extrorse, protected by outer and/or inner indusia or rarely not protected; spores tetrahedral and trilete, or reniform and monolete (Smith et al. 2006).
Two species plus two species with hybrid origin are currently recognized (Thomson 2012, Zhou et al. 2014, Schwartsburd et al. 2018. In addition, a total of ca. 20 morpho-taxa are also recognized as infra-specific entities, such as subspecies, varieties, forms, or combinations of more than one rank (e.g., Tryon 1941, Page 1976, Thomson 2012, Schwartsburd et al. 2018  . The most common taxon in southeastern Brazil is P. esculentum subsp. arachnoideum, which invades crops and is toxic for cattle, horses, and human ingestion (Schwartsburd et al. 2018).