Chamaecrista nictitans subsp. disadena (Steud.) 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 2: 455-918.

• Family

  Caesalpiniaceae

• Scientific Name

  Chamaecrista nictitans subsp. disadena (Steud.) H.S.Irwin & Barneby

• Type

  Cassia disadena Steudel, Flora (Regensb.) 26: 760. 1843.—Typus infra sub. var. disadena citatur.

• Synonyms

  Cassia disadena Steud., Cassia stenocarpa Vogel, Chamaecrista stenocarpa (Vogel) Standl.

• Description

  Species Description - Pedicels in fruit up to 6—14(—21) mm, potentially but not always actually longer than in other subspp. of Ch. nictitans, the corolla either subrotate or strongly asymmetric, the long abaxial petal up to (5.5—)6—15 mm; style either linear and 3-5.5 mm or dilated upward and only 1.4-3.3 mm; androecium 10-merous; petiolar gland stipitate, in profile tack-, trumpet-, urn-shaped or broadly claviform, taller than diam of the head.—S. Mexico to s.-e. Brazil and Paraguay.

• Discussion

  Of all our sometimes arbitrarily delimited infraspecific taxa in Ch. nictitans, the present subspecies is the most difficult to define or to defend from criticism. It accommodates those monocarpic chamaecristas with emphatically stipitate petiolar glands which differ from subsp. nictitans in the longer pedicels and larger, or if scarcely larger then more regular, subrotate corolla. It is approximately equivalent to C. stenocarpa Vog. as understood by Bentham and many subsequent writers, although when large-flowered and represented by severed stems unaccompanied by data on duration, partly equated by Bentham with C. glandulosa. The subspecies stands in a critical relation to the whole complex of Neotropical Chamaecristae Mimosoideae in the sense that the monocarpic duration of Ch. nictitans sens. lat. is here combined with the flower of Ch. glandulosa, confirming Otto Kuntze’s doubtless biologically real while taxonomically monstrous concept of a huge multiracial species within which no substantial discontinuities have yet developed. We divide subsp. disadena into two intergradient and largely sympatric varieties, a longistyled presumably outcrossing var. disadena which is sometimes almost impossible to disentangle from shrubby or at least strongly perennial Ch. glandulosa, and a brachystyled, presumably autogamous var. pilosa which in Central America fades imperceptibly into subsp. nictitans var. jaliscensis.

• Distribution

  Brazil South America| Mexico North America| Paraguay South America|