Cassia tetraphylla var. colombiana H.S.Irwin

  • Authors

    Howard S. Irwin

  • Authority

    Irwin, Howard S. 1964. Monographic Studies in Cassia (Leguminosae-Caesalpinioideae). I. Section Xerocalyx. Mem. New York Bot. Gard. 12 (1): 1-114.

  • Family

    Caesalpiniaceae

  • Scientific Name

    Cassia tetraphylla var. colombiana H.S.Irwin

  • Type

    Holotype (NY) : Colombia, Santander, "18 km S of Socorro, in thicket, alt. 1200 m." H. St. John 20538. 28 June 1944. Isotypes (MICH, UC, US).

  • Description

    Species Description - Planta fruticosa aut suffruticosa, ad 1.5 m alt., ramis pubescentibus horizontalibus aut ascendentibus. Stipulae foliaceae adpressae persitentes aut raro cacluceae, late lanceolatae aut ovatae, apice acuto obtusove 0.8-1.6 cm long., 3.5-7.8 mm lat., glabrae interdum ciliolatae integrae. Petiolus 4.1-7.8 mm long., canaliculo adaxiali puberulente ad pubescentem aut raro glabrum, superficie abaxiali maxima ex parte pubescente; rachis 0.3-0.5 brevior quam petiolus, terminaliter aristata. Gians 1 scutellata, 0.7-1.2 mm lat., sessilis aut subsessilis. Foliola bijugata, paribus subaequis aut pari inferiore paululum maiore per pulvinulum parvum arcuatum atrum aut brunneum c. 1.0 mm long, sessilia, anguste oblonga aut oblanceolata ad abovata, quasi obliqua, recta aut paulum inflexa, glabra, interdum glauca, firme membranacea aut subcoriacea, 1.4-2.2 cm long., 3.7-9.2 mm lat.; margines integri, interdum distaliter ciliolata, apice rotundato aut raro inflexo-obtuso. Flores axillares plerumque singulares aut in racemis abbreviatis paucas flores habentibus raro occurrentes; pedicelli recti aut sursum arcuati, flavo-pubescentes aut -puberulentes, raro glabri, 2.5-3.8 cm long., c. 0.5 mm crass, dum florentes, usque ad 4.8 cm long., 0.9 mm crass, dum frugentiferes; bracteae 2, late ovatae, 2.0-3.5 mm long., 1.5-3.0 mm lat.; bracteolae suboppositae ovatae divergentes, 4.0-5.8 mm long., 2.4-2.8 mm lat.; sepala lanceolata glabra, 1.0-1.6 cm long., 3.8-5.4 mm lat.; petala flava, 1.8-2.4 cm long., 1.5-2.0 cm lat.; stamina flava; ovarium flavo- aut subcinereo-pilosum. Siliqua anguste oblonga, 3.4-4.8 cm long., 7.0-9.1 mm lat., superficies plana aut super semina non profunde cristata, flavo-hirsuta, secundum suturas copiose hirsuta. Semina levia brunnea aut atro-brunnea, interdum flavo-brunnea, paululum compressa, 4.7-5.3 mm long., 1.7-2.2 mm lat. Shrub or subshrub to 1.5 m, the pubescent branches horizontal or ascending. Stipules foliaceous, or rarely caducous, broadly lanceolate or ovate, apex acute or obtuse, 0.8-1.6 cm long, 3.5—7.8 mm broad, glabrous, sometimes ciliolate. Petiole 4.1-7.8 mm long, the adaxial groove puberulent to pubescent or rarely glabrate, the abaxial surface mostly pubescent; rachis 0.3-0.5 as long as petiole. Gland 1, scutellate, 0.7-1.2 mm broad, sessile or subsessile. Leaflets bijugate, the pairs subequal or the inferior pair slightly larger, joined to rachis by a small arcuate black or brown pulvinule ca. 1.0 mm long, narrowly oblong or oblanceolate to obovate, somewhat oblique, straight or very slightly in flexed, glabrous, sometimes glaucous, firmly membranaceous or subcoriaceous, 1.4-2.2 cm long, 3.7-9.2 mm broad; margins sometimes distally ciliolate, the apex rounded or rarely inflexed-obtuse. Flowers usually solitary or rarely in abbreviate few-flowered racemes; pedicels straight or arching upward, yellow-pubescent or -puberulent, rarely glabrous, 2.5-3.8 cm long and ca. 0.5 mm thick in flower, up to 4.8 cm long and 0.9 mm thick in fruit; bracts 2, broadly ovate, 2.0-3.4 mm long, 1.5-3.0 mm broad; bracteoles subopposite, ovate, divergent, 4.0-5.8 mm long, 2.4-2.8 mm broad; sepals lanceolate, glabrous, 1.0-1.6 cm long, 3.8-5.4 mm broad; petals 1.8-2.4 cm long, 1.5-2.0 cm broad; ovary yellow- or grayish-pilose. Pod narrowly oblong, 3.4-4.8 cm long, 7.0-9.1 mm broad, faces flat or shallowly sulcate between the seeds, yellow-hirsute, copiously so along the sutures. Seeds slightly compressed, 4.7-5.3 mm long, 1.7-2.2 mm broad. Chromosome number: not determined.

    Distribution and Ecology - Distribution: Western Colombia, Edos. Santander, Caldas, and Cundinamarca, east to Vaupés. Occurring mainly in mountain savannas and low open woods from 1000-5000 feet elevation.

  • Discussion

    This variety, similar to C. tetraphylla var. tetraphylla except for the large stipules and the yellow pubescence of floral structures, probably represents the full expression of what was approached by C. pulchra H. B. K. However, as is noted under C. tetraphylla var. tetraphylla, C. pulchra, as conceived by its authors, falls well within the range of variability of C. tetraphylla var. tetraphylla in northern South America, and therefore is reduced to synonymy under that variety. The present taxon, in addition to its morphological distinctness, is separated from the nearest known populations of C. tetraphylla var. tetraphylla by an east-west gap of about 400 miles across the Llanos of eastern Colombia. However, it is more or less contiguous with a small localized population of C. tetraphylla var. brevipes (Benth.) Irwin in Edos. Meta and Vaupés. Intergradation between these taxa is evidently slight for no intermediate variants have been seen, and each retains its own peculiarities in areas of sympatry.

    The only significant variation observed in C. tetraphylla var. colombiana concerns stipule persistence; specimens from Vaupés show stipule loss before leaflet expansion and internodal elongation have been completed. This may be the result of gene exchange with C. gracilis Kunth, a species of the upper Orinoco drainage which frequently also has caducous stipules, but as yet there is no clear morphological evidence to support this suggestion.

  • Distribution

    Colombia South America| Santander Colombia South America| Caldas Colombia South America| Cundinamarca Colombia South America| Vaupés Colombia South America|