Cassiinae pt 1 NY-Botanical_gardens_Vol. 35_1 - Copy.pdf - Antbase

1982] CASSIINAE—SENNA 175
±3.5-8.5 X 1.1-1.7 cm, abruptly contracted at both ends, the thin valves becom­
ing papery castaneous and ultimately blackish, at first thinly or remotely pilosulous,
then glabrate; seeds biseriate, compressed-obovoid, ±5.5-6 x 3.1-3.5
mm, the testa blackish-brown, briUiantly lustrous, crackled, exareolate.—Collections:
26.
Caatinga, disturbed semideciduous woodland and cerrado, sometimes on sta-
bUized dunes near the coast, from near sea-level n.-e.-ward but up to 1000 m in
Bahia, scattered over n.-e. BrazU from s. Ceara e. to interior e. Paraiba, s. to n.
and e.-centr. Bahia e. of Rio Sao Francisco (possibly adjacent Alagoas), on Chapada
Diamantina extending s. to Sa. Agua da Rega and the middle Paragua^ii
vaUey; apparently disjunct, in a possibly distinct, as yet poorly known form, on
coastal dunes of Ceara and Paraiba.—Fl. (XII-)I-VI.
Senna rizzinii closely resembles S. chrysocarpa, which see for differential com­
mentary. In general habit and details ofthe fohage it is also uncomfortably simUar
to partly sympatric S. macranthera var. pudibunda. The mature pedicels of var.
pudibunda are longer (2.5-5, not less than 2 cm), its petals when fully expanded
are longer (up to 22-30, not 14-19 mm), the dimorphism of its fertUe stamens is
more pronounced, and its relatively many-ovulate gynoecium ripens to a longer
pod. A feature common to both is a relatively long style (3-5 mm) and both are
adapted to a seasonally arid regimen. Collectively these two entities go far to
bridge the morphological gap between S. chrysocarpa and S. macranthera sens.
lat., species traditionally referred to different groups because of the androecial
differences. The technical characters of 5. rizzinii and S. macranthera var. pudi­
bunda need careful field-study in northern Bahia, flowers and fruits from the
same populations, up till now not available for comparative study, being especially
wanted.
In lieu of the holotypus we have taken as representative of Cassia granulata
specimens from the type-locality, between Alagoas and Paulo Afonso, A. P.
Duarte 14180, NY, RB, which correspond closely with the description.
38. Senna tapajozensis (Ducke) Irwin & Barneby, comb. nov. Cassia tapajozensis
Ducke, Archiv. Jard. Bot. Rio de Jan. 4: 57. 1925.—"Habitat in regione
fluminis Tapajoz medii loco Repartigao (Herb. Jard. Bot. Rio n.
16.990) et ad ejusdem flumen infra cataractas infimas prope Itaituba
(. . . n. 16.989) ... 1. A. Ducke, florif. maio et junio."—Lectoholo­
typus, R. 16990, R!
Cassia chrysocarpa var. (?) macrocarpa Bentham in Martius, Fl. Bras. 15(2): 101. 1870.—"in
silvis Capoeiras ad Manaos prov. do Alto Amazonas: Spruce n. 7775."—Holotypus, collected
in 1852 (fl, fr jun), K (hb. Benth.)!
Weak, softly woody shrubs, in open places diffusely ascending or traihng, in
brush or forest-savanna ecotone becoming sarmentose with drooping or pendu­
lous branchlets, at anthesis 1-3 m, strigulose-pUosulous throughout with fine incurved,
widely spreading or (on lvs) forwardly appressed hairs up to 0.1-0.25
mm, the angulately ribbed hornotinous stems commonly densely so, often sub-
velutinous, the thinly chartaceous lfts moderately lustrous dark green above, dull
but little paler beneath, puberulent on both faces, the always minutely pUosulous
inflorescence variable in form, usually thyrsiform and leafy-bracteate, sometimes
paniculate, the uppermost lvs sometimes much reduced and the distal fls then
becoming well exserted.
Stipules subulate or linear-setiform, straight or falcate, 2.5-7 mm, at base
0.3-0.6 mm wide, caducous and often lacking from flowering spms.