Cassia lundii Benth.

Authors

Howard S. Irwin, Rupert C. Barneby

Authority

Irwin, Howard S. & Barneby, Rupert C. 1978. Monographic studies in Cassia (Leguminosae, Caesalpinioideae). III. Sections Absus and Grimaldia. Mem. New York Bot. Gard. 30: 1-300.

Family

Caesalpiniaceae

Scientific Name

Cassia lundii Benth.

Type

Holotypus, dated X.1834 (fl.) Lund 188, C (3 sheets, 2 unnumbered)! one = F Neg. 21819 = NY Neg. 6735!

Description

Species Description - Lowly but sturdy subshrubs with few or up to ±20 stems 1-3 dm obliquely ascending from an ultimately massive knotty xylopodium, below the densely black-setulose, glutinous inflorescence either almost glabrous or except for always glabrous lfts both viscid-villosulous and livid-setulose, the simple stems often abruptly enlarged at base, few-lvd, the multifoliolate lvs stiffly divaricate, the leathery concolorous lfts turned edgewise to the meridian and not dorsoventrally differentiated, the inflorescence of 1-5 (when more than 1 fasciculate), vertically erect, many-fld racemes often nearly as long or longer than the leafy stem. Stipules erect, firm, linear-lanceolate or setiform, 4-10 mm, becoming dry and fragile, ciliolate or setulose, tardily deciduous. Lvs subhorizontally spreading, (0.7-)1-2.3 dm, shortly petioled; pulvinus seated on a pronounced corneous lf-spur, squatly ovoid, 1.5-2.5 mm, often slightly wider than long; petiole 2-3.5(-4) cm, at middle 0.9-1.7 mm diam, from middle upward obtusely bicarinate ventrally, shallowly narrowly grooved; rachis stiffly tapering, (5-)7-18 cm, strongly dilated at each pair of lfts; lfts (3-)5-9 (-1 0) pairs, spreading at right angles to the axis, on squatly dilated, when dry coarsely wrinkled pulvinules 0.6-1 mm, either subuniform in size or diminishing upward, in outline suborbicular or broadly deltate-ovate, at apex rounded, obscurely emarginate, or broadly deltate, muticous or minutely mucronulate, 1.7-4 x 1.6-3.6 cm, at base asymmetrically semi-cordate, the broadly rounded proximal basal angles of each pair imbricated across the ventral side of the rachis, their margins all entire, pallidly corneous but sharp-edged, the blades coriaceous, dull-olivaceous and commonly glaucescent both sides, not glutinous, the slender midrib and 4-6(-7) pairs of major secondary veins equally but not very sharply prominulous both sides, the connecting tertiary venation irregular or obscure, not forming a regular mesh. Racemes 1-5, commonly solitary from tip of the leafy stem or if more than one arising together from a condensed leafless axis to 1 cm, or from axils of 1-2 approximate distal lvs, mostly 20-45-fld, including the short peduncle (1.5-)2-4 dm, several successive flowers simultaneously expanded and these standing well below the unopened buds; bracts narrowly subulate, 2-5.5 m, persistent but becoming dry and fragile; pedicels ascending, 1-4 cm, usually progressively shorter upward along the raceme, the lowest mostly at least 2 cm, all bracteolate 1-6 mm below calyx; bracteoles resembling bracts but scarcely half as long, deciduous; buds plumply ovoid or red-tinged, oblong-elliptic obtuse (7-)7.5-11 x 2.8-5 mm, at anthesis widely expanded; petals yellow, the four plane ones patently ascending, little heteromorphic, broadly to narrowly flabellate-cuneate, to (14-)15-18.5 x 9-16 mm, the fifth oblanceolate, somewhat shorter, coiled; ovary densely black-setulose; ovules (4-)5-7(-8). Pod ascending, narrowly oblong, (2.5-)3.5-6 x 0.7-0.9 cm, the valves minutely villosulous and glutinously hispidulous with fine setules; seeds (1 seen) claviform-compressed, ±6x3 mm, the testa becoming lustrous black, obscurely lineolate. — Collections: 20.

Distribution and Ecology - Campo, cerrado, sometimes in fields, on red lateritic or sometimes calcareous soils, 950-1250 m, resistent to fire, locally plentiful on the headwaters of Rio Corumba in Distrito Federal and immediately adjoining Goias, extending thence n.-e. into s. Sa. Geral do Parana and s.-e. across Sa. da Tiririca to the drainage of Rios Urucula and Paracatu in w. Minas Gerais. — Fl. VI-XI. "Habitat in campis ad Rio S. Francisco: Lund."

Discussion

A lowly suffruticose cassia with up to twenty stems obliquely ascending from a knotty xylopodium, the smooth leathery glaucescent foliage contrasting with proportionately long simple, sweetly viscid and densely livid-setulose racemes of yellow flowers. The leaves are characteristic, the pulvinus and pulvinules, alike swollen but rigid, holding the leafstalk stiffly horizontal and the suborbicular or heart-shaped leaflets turned neatly edgewise to the noon sun. Both leaf and leaflets stand on a dilated nodelike swelling, from which they disjoint readily when dried. The terminal racemes which rise vertically, solitary or few together, from the apex of the simple stems, bear many flowers simultaneously expanded in an intense but brief period of bloom. The stage of maturity passes rapidly upward along the raceme-axis, the pods therefore coming to fruition all together.

Distribution

Minas Gerais Brazil South America| Distrito Federal Brazil South America| Goiás Brazil South America| Brazil South America|