Chamaecrista juruenensis (Hoehne) H.S.Irwin & Barneby

• Region

  South America

• Country

  Brazil

• State/Province

  Mato Grosso

• County/Municipio

  Barra do Garças Mun.

• Locality

  Serra do Roncador. 266 km along new road NNE of village of Xavantina (6.5 km due NNW of Royal Society-Royal Geographic Society Base Camp.) 6.2 km N along main road from turnoff to Base Camp

• Elevation

  Alt. 450 m. (1476 ft.)

• Coordinates

  -12.85, -51.75

• Distribution

  Map all specimens of this taxon

FLORA OF BRAZIL
STATE OF MATO GROSSO
SERRA DO RONCADOR
Caseta.
Municipio de Barra do Gar ras: 266 km along new road NNE of
village of XAVANTINA. (O«5 km due |0nl of Royal Society-
Royal Geographic Society Base Camp. Base Camp is at 12°51’S. 51°45’W.)
Ait. ca. 450 m. 6,2 km N along main road from
turnoff to Base Camp.	6 Sept 1968
(Area of 10 km' radius around Base Camp Is situated on crefet of the Serra do
Roncador, a gently-sloped divide between Xingu drainage (via Rio Suiá Migu)
to west and Araguáia drainage (via Rio das Mortes) to east. The yet undissected
few-km wide crest is flat or gently rolling with a few low lateritic scarps and
ridges. Brook valleys with very gentle to moderately steep slopes. Base Camp
area is exactly at climatic boundary between Amazonian forest region and central
Brazil “cerrado” region (savanna sens. lat.). North-western half of area is covered
with the outer edge of the continuous Amazonian forest, here a slightly semide-
ciduous dry mesophytic forest 15-18 m tall on the upland, taller along the
seasonally dry brooks. Southeastern half of area has, on the upland, xeromorphic
semideciduous cerrado, in the form of medium-tall open scrub or tree-and-scrub
woodland, with evergreen gallery forests 20-30 m tall along the permanent brooks.
Usually a band of seasonally marshy grassy campo, a few meters to a few tens
of meters wide, borders the gallery forests, separating them from the cerrado,
but where the campo is lacking, the cerrado grades directly into gallery forest
through a narrow band of its arboreal form, “cerradao". The campos usually
have scattered circular groves of cerrado scrub several meters in diameter on
slightly raised soil, each with a termite mound. On the upland the cerrado region
grades into the continuous dry forest region through a few-km wide ecotone of
cerradáo. Underlying rock is various kinds of sandstone, giving rise to slightly
clayey fine-sandy deep latosols, sterile and reddish or yellowish-tan with almost
no humus on upland under cerrado, and dark red with more clay under dry
forest. In restricted areas under cerrado, small laterite blocks or quartz pebbles
may form a thin permeable subsurface layer, or the upper soil layer may be
purely of laterite pebbles. Valley soils are deep light gray fine sand with little
or no clay, sterile on drier upper slopes, black with humus in upper layer on
moister or soaking lower slopes and floors. Shales underlie soils in a few valleys.
At this date the Base Camp region has not yet been settled; the forests are virgin;
the cerrado and campo are uncut and ungrazed, but have been subjected to ground
fires set by Indians every 3^5 years. In the cerrado, these infrequent fires
temporarily reduce density of the lower shrubs but otherwise have no effect
on the physiognomy.)	¿	.___,, _ .	» . •
Habitat of this n.°; secondary shrubbery at roadside
through dry mesophytic forest (Amazon forest
edge)« This nfi: shrub 1 m tall, with
spreading branches* Petals golden-yellow?
leg. George Eiten & Liene T. Eiten, n.° 8590
______(from planté)
nistrihifofl fry tviP Instituto de Botánica, S&o Paulo
00960474