Two new species of Janusia ( Malpighiaceae ) from Brazil

(Two new species of Janusia (Malpighiaceae) from Brazil). Two new Brazilian species of Janusia are described and illustrated: Janusia diminuta, restricted to the Restinga vegetation in Northern Rio de Janeiro State; and Janusia paraensis, which is known from the Amazonian savanna vegetation in Pará State. Their diagnostic features are pointed out and a discussion of their relations to other species of Janusia are provided herewith.


Introduction
Janusia A.Juss.comprises 15 species and is mostly a Brazilian genus, predominantly found in dry areas (Cerrado, Caatinga vegetation, Restinga vegetation, and rocky outcrops, Sebastiani 2010).Janusia is nested within the tribe Gaudichaudieae, along with Aspicarpa Rich., Camarea A.St.-Hil., Cottsia Dubard & Dop, and Gaudichaudia Kunth.Such tribe is characterized by the reduction of the androecium and gynoecium and the presence of cleistogamous flowers (Davis et al. 2002).Janusia is characterized by five or six fertile stamens and a 3-carpellate gynoecium with a single gynobasic style (Sebastiani 2010), but only J. guaranitica (A.St.-Hil.)A.Juss. and J. schwannioides W.R.Anderson present cleistogamous flowers.
According to phylogenetic analysis performed by Davis & Anderson (2010), the genus Janusia is not monophyletic, because Aspicarpa, Gaudichaudia and Janusia species appear mixed in a well supported clade.

Results and Discussion
Janusia diminuta is only known from the Restinga vegetation of Armação de Búzios, on the Northern coast of Rio de Janeiro State.Flowering and fruiting specimen was collected in May.
Janusia diminuta is characterized by the reduced dimensions of floral structures and the reduction of its inflorescence, which shows one or two sterile rachis above the corymb stalk and by its samara with one pair of lateral wings.Such features are shared with J. anisandra (A.Juss.)Griseb.and J. caudata (A.Juss.)Griseb.(table 1).Both species occur mainly in Caatinga vegetation, whereas J. anisandra occurs in the states of Ceará, Pernambuco, Alagoas, Paraíba, Bahia and Minas Gerais, J. caudata is common in the states of Pará, Maranhão and Piauí.Janusia diminuta is known only for the State of Rio de Janeiro.
The distribution of Janusia diminuta is related to J. hexandra, a species commonly found in the states of Rio de Janeiro, Espírito Santo and Bahia.Both species present sericeous hairs, fimbriate petals and anthers with sparse malpighiaceous hairs, but they differ in their inflorescence pattern, the size of their floral structures and the fruit morphology.While J. diminuta shows reduced floral structures and winged samara, J. hexandra has larger flowers and fruits lacking lateral wings, but presenting little extensions on the nut ribs.With regards to the floral dimensions, some structures are clearly smaller in J. diminuta than in J. hexandra, such as the sepal glands and the posterior petal (Sebastiani 2010).Another important feature to distinguish J. diminuta from J. hexandra is their habitat.Janusia diminuta was only found in Restinga vegetation and J. hexandra occurs within tropical forests (Matas higrófilas sul-baianas in Bahia State and Matas de tabuleiro in Espírito Santo State) as well as on borders of secondary vegetation (in Rio de Janeiro State).
The only collection analyzed for J. diminuta came from a sustainable protected area (Área de Proteção Ambiental do Pau-Brasil).This reserve was visited a few times, but no specimens were found.Throughout these visits, intense anthropic action was observed, which may represent a major threat to the flora and fauna in such area.
appendices in J. janusioides, absent in J. paraensis.However, both have a short peduncle, yellow fimbriate petals, posterior petals with a pubescent claw, connective exceeding the locules, and nuts without lateral wings.Janusia paraensis differs from J. prancei by the absence of stipules, stipitate glands on the lamina, a pubescent claw, and a connective not exceeding the locules.On the other hand, J. prancei has triangular stipules, orbicular glands on the lamina, not pubescent claw, and connective exceeding the locules.
However, none of the collections of J. paraensis analyzed was obtained in protected area, which may contribute to species endangerment.
other petals in the same flower.
others petals in the same flower.