Monographs Details: Senna pendula var. paludicola H.S.Irwin & Barneby
Authors:Howard S. Irwin, Rupert C. Barneby
Authority: Irwin, Howard S. & Barneby, Rupert C. 1982. The American Cassiinae. A synoptical revision of Leguminosae tribe Cassieae subtrib Cassiinae in the New World. Mem. New York Bot. Gard. 35, part 1: 1-454.
Description:Variety Description - Cassia bicapsularis fma. pilosa Chodat & Hassler, Bull, Herb. Boissier II, 4: 691. 1904.— ". . .in sabulosis insulae Choco-y pr. Concepcion [Paraguay], Sept., n. 7361."—Holotypus, G! isotypus, NY!Shrubs 1.4-4 m, glabrous throughout or the stems remotely puberulent and the lfts barbellate dorsally in the further basal angle of midrib; petiolar gland between proximal pair of lfts only; lfts (3-)4(-5) pairs, the distal pair broadly or narrowly obovate (2-)2.5-4(-4.5) x (0.75)0.85-1.4(-l.9) cm, the secondary camptodrome veins 8-12 on each side of midrib, the tertiary venulation either sharply prominulous dorsally or subimmersed; innermost sepal 7.5-11 mm; longest petal (13-)15-20 mm; blade of staminodes oblong slightly dilated upward 3-4.3 x 1.1-1.8 mm; filaments of 2 long abaxial stamens 10-17 mm, their anther 6.2-8.5 x 1.52 mm, tapering into the truncate apex; ovary glabrous or thinly pilosulous; style 1.5-2.5 mm, abruptly hooked at apex; ovules 76-104; body of pod cylindric 1018 x 0.9-1.4 cm, the seeds biseriate.—Collections: 17. [Key: "Lfts obovate or oblanceolate, rarely elliptic-oblanceolate, broadest above (exceptionally near) the middle; range of the whole sp. Style at and after anthesis 1.5-5 mm and the 2 long abaxial filaments 6-11 mm. Plants of the Orinoco valley in Venezuela, of the Amazonia Hylaea, of the Paraguai basin, and of coastal s.-e. Brazil. Lfts penniveined on lower face, the raised tertiary venulation, if present, weak and erratic, not forming a close, sharply defined reticulum; allopatric; seeds 2-seriate. Style only 1.5-3 mm; Amazonia s.-ward. Sepals membraneous; blade of staminodes linear-oblong or -oblanceolate, 3-4.3 X 1-1.8 mm, 2-3 times as long as wide; 2 long anthers (6.2-)7-12 mm. Plants of Paraguai valley downstream from the Pantanal in w. Mato Grosso, Brazil to n.-e. Argentina; longest interior sepal 7.5-11 mm and petiolar gland at first pair of lfts only."]

Distribution and Ecology - Thickets, woodland margins, shores of temporary lakes or ponds, riverbanks and low swampy grasslands below 250 m, widespread and locally common in the Paraguay valley between 19° and 30°S, from the Pantanal in w. Mato Grosso, Brazil and the lower Pilcomayo valley in Paraguay s. to Corrientes and adjoining Santa Fe, Argentina, extending across Corrientes to the Uruguay River, therefore to be expected in w. Rio Grande do Sul, Brazil and possibly extreme n. Uruguay; one record from wet savanna on rio Yacuma near 14°S in Beni, Bolivia.—Fl. (XII-)II-VI.

Discussion:In our key to the varieties of S. pendula we have stressed a difference between intricately, sharply reticulate and penniveined but only weakly, indefinitely reticulate leaflets. As a general rule this criterion is practical and easily applied, but the tertiary and subsequent venulation in var. paludicola is variable and sometimes difficult to classify. In context of its dispersal, however, var. paludicola is instantly recognized by the short hooked style and proportionately short abaxial filaments, the immediately vicariant or narrowly overlapping vars. missionum and glabrata being conspicuously longistylous and different in outline of the staminodes. A close match for its androecium is found in the maritime allopatric var. ambigua, but this has the staminodes of var. glabrata and a relatively few- ovulate, laterally compressed pod with uniseriate seeds. The also closely related var. tenuifolia, distantly allopatric in the Hylaean forest, has almost the same androecial apparatus but differs in the thinly membranous foliage, an ampler calyx and an extraordinarily drawn out pod mostly 2-3 (not 1-2) dm long. The var. paludicola has been treated in Argentine literature as part of a polymorphic Cassia bicapsularis and referred by Lasseigne (in adnot.) to a broadly conceived C. pendula.
Distribution:Mato Grosso Brazil South America| Paraguay South America| Corrientes Argentina South America| Santa Fé Argentina South America| Rio Grande do Sul Brazil South America| Uruguay South America|