wide, ellipsoid, cupule 3 - 4.4 mm long, 3.2 - 4 mm wide, pedicel 2.0 - 5.5 mm long, 0.9 - 1.2 
mm wide, tepals wholly persistent, upper part usually marcescent. 
Flowers in January through May. Fruits April to June. Between 750 and 1850 m altitude, 
in rocky areas with iron ores. Vegetation type: campo cerrado, campo aberto, canga, campo 
rupestre. Although the species seems to be common, it is restricted to a rather small region in the 
area near Belo Horizonte (Minas Gerais) in Brazil. 
General appearance of C. gquadrangulum resembles C. amplexicaule from Mexico. The 
combination, however, of sharp angular twigs, almost sessile leaves with cordate bases, along 
with stamens of whorl III with a tendency to reduced or aborted upper sporangia, distinguish the 
former species from the latter one. The large disjunction itself, however, does not rule out 
necessarily the possibility of some relationship between the two species; as the cladistic analysis 
of relationships among the species suggests. 
Specimens examined. BRAZIL. Minas Gerais. In monte serra da Piedade, E. Warming 
693 (C); Retiro das pedras, aprox. 3 km ao S de Belo Horizonte, F. Lorea 5585 (FCME); Serra 
da Piedade, aprox. 6-7 km ao NE de Belo Horizonte, F. Lorea 5589 (FCME); Belo Horizonte, 
Serra do Curral, M. Magalhaes 1467 (MG); Entre Congonhas e Belo Horizonte km. 386, E. 
Pereira & Pabst 2408 (MG, RB (3 sheets)); Belo Horizonte, BR 3, a 15 km de Belo Horizonte, 
L. Roth 1724 (RB); Serra da Piedade, E. Pereira & Pabst 3537 (RB); Near BR-31, ca. 35 km E 
of Belo Horizonte, in upper shrub-covered slopes of Serra da Piedade, H.S. Irwin et al. 30400 
(MO, ENCB); Belo Horizonte, Serra do Taquaril, M. Barreto 7465 (F); without precise locality, 
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