Abstract Detail

Floristics & Taxonomy

Souto, Flávio Sousa [1], Queiroz, Rubens Teixeira de [2], Agra, Maria de Fátima [3].

Senna pluribracteata (Leguminosae, Caesalpinioideae), a New Species from Atlantic Forest of Northeast Brazil, with Notes on its Leaf Anatomy.

The genus Senna Mill. (Leguminosae, Caesalpinioideae) comprises ca. 330 species, of which 280 occur in the Americas, and the rest are distributed in Australia, Africa and/or Madagascar. About 81 species are registered to Brazil, 30 of which are endemic. In this work, a new species, Senna pluribracteata F.S.Souto & R.T.Queiroz, from the Atlantic Forest Northeast of Brazil, is described and illustrated based on a field collection, and the analysis of Senna collections at RB and the main herbaria of Brazil (EAN, HST, IPA, JPB, MAC, PEUFR, RB, UFP, and UFRN). In addition, anatomical studies were carried out performed according to the usual methodologies for plant anatomy and analyzed using light microscopy. Morphologically, Senna pluribracteata is related to a group of four species of Senna sect. Chamaefistula ser. Bacillares: S. macranthera (DC. ex Collad.) H.S.Irwin & Barneby, S. pinheiroi H.S.Irwin & Barneby, S. rizzinii H.S.Irwin & Barneby, and S. rugosa (G.Don) H.S.Irwin & Barneby, although, S. pluribracteata has a set of distinctive morphological and anatomical characters that differentiate it: strigose branches, leaves with two extrafloral nectaries between pairs of leaflets (occasionally just above the first pair); large and conspicuous elliptic bracts 7.0–9.0 mm long, along the inflorescence peduncle; epidermis on the abaxial surface is conspicuously and compactly papillose; the rounded leaflet margins have palisade parenchyma near the apex; mesophyll dorsi-ventral with a single layer of palisade parenchyma, with isodiametric cells occupying approximately 60% of that structure; the petiole has a somewhat pentagonal shape, and is planar adaxially; the rachis is obdeltoid and planar adaxially. The specific epithet refers to the amount of bracts on inflorescence peduncle, which represent one of the main diagnostic characters of the new species. The plant morphology and the leaf anatomical characterization of S. pluribracteata are presented, as well as its affinities with allied taxa of Senna ser. Bacillares are discussed.

1 - Universidade Federal de Pernambuco, Departamento de Botânica, Recife, Pernambuco, Brazil
2 - Universidade Federal da Paraíba, Departamento de Sistemática e Ecologia, João Pessoa, Paraíba, Brazil
3 - Universidade Federal da Paraíba, Departamento de Biotecnologia, João Pessoa, Paraíba, Brazil

Keywords:
Atlantic Forest
Cassia
Fabaceae
Senna sect.  Chamaefistula
Senna ser. Bacillares.

Presentation Type: Poster
Session: P2, Floristics & Taxonomy Posters
Location: Virtual/Virtual
Date: Tuesday, July 20th, 2021
Time: 5:00 PM(EDT)
Number: P2FT012
Abstract ID:913
Candidate for Awards:None