On this French website the Staurogyne sp. from Rio Cristalino is thought to be
Staurogyne sylvatica:
http://www.aquaportail.com/fiche-pla...sylvatica.html
But that's apparently an error. There's a paper about new Staurogyne species from Brazil (Braz & Monteiro 2006):
http://www.scielo.br/pdf/rbb/v29n4/06.pdf
S. sylvatica is described there as a semi-shrub up to 1 m tall, with lilac flowers.