Declieuxia dusenii Standl.

  • Authority

    Kirkbride, Joseph H., Jr. 1976. A revision of the genus Declieuxia (Rubiaceae). Mem. New York Bot. Gard. 28 (4): 1-87.

  • Family

    Rubiaceae

  • Scientific Name

    Declieuxia dusenii Standl.

  • Description

    Species Description - Subshrub or perennial herb 10-75(-100) cm tall with several erect stems, the stems terete, glabrous or glabrate to puberulous, the internodes (0.4-)1-8(-9.5) cm long, with branchlets bearing 1 or 2 pairs of small leaves in some leaf axils. Stipules unidentate, linear-subulate with the apex terminating in a conical gland or foliar, the foliar stipules narrowly elliptic to linear, acute at apex, cuneate at base, glabrous, the linear-subulate stipules glabrous or glabrate to sparsely scabrous or to puberulous, 1.3-27 x 0.1-3 mm, usually decurrent. Leaves opposite, petiolate, the petiole winged, 1-15 mm long, glabrous or glabrate to scabrous; blade chartaceous, narrowly elliptic to occasionally elliptic or ovate, acute at apex, attenuate to shortly attenuate at base, 0.8-6 x 0.3-2 cm, 1.4-4(-4.7) times longer than wide, venation pinnate with 3-6 arcuate lateral veins on each side, the prominulous midrib and faintly prominulous lateral veins scabrous above, the upper intercostal areas scabrous or very rarely glabrous to glabrate, the prominent midrib and prominulous lateral veins glabrous to sparsely scabrous beneath, the lower intercostal areas glabrous, the tertiary venation closed reticulate or obscure. Inflorescences terminal and axillary modified cymes, pedunculate, 0.7-7.5(-9) x 0.4-3 cm, with 10-225(-250) flowers, with 2-12(-22) axes, the axes terete, (0.1-)0.4-1.9 cm long, glabrous or glabrate to puberulous or rarely villous; peduncle terete, 0.2-4.5(-5.5) cm long, glabrous or glabrate to puberulous or rarely villous, with 2 dichasial or 2 larger bracts at the apex, the enlarged bracts narrowly oblong or narrowly elliptic, acute at apex, straight or cuneate at base, (0.4-)2-10 x 0.4-1.2 mm, glabrous or glabrate or rarely with the adaxial surface scabrous. Flowers subpedicellate with the pedicels terete, 0.1-0.3 mm long, glabrous to glabrate or very rarely with 2 or 3 long curly hairs, dichasial bracts narrowly oblong to linear or linear-sublate to triangular or narrowly elliptic, acute at apex, 0.7-1.6 x 0.12-0.5 mm, glabrous; hypanthium transverse to rarely transversely broadly elliptic or very broadly ovate in outline, 0.4-0.6 x 0.6-0.9 mm, glabrous or glabrate or with puberulous patches or rarely a few long curly hairs; calyx lobes narrowly oblong to oblong or narrowly triangular to triangular, acute to broadly acute or rarely subobtuse at apex, 0.2-0.7 x 0.1-0.3 mm, glabrous or rarely with a few long curly hairs; corolla blue, salverform, the tube 1.7-4.8 mm long, orifice 0.8-1.8 mm in diam, 0.3-0.8 mm at base, exterior glabrous, interior with a sericeous, moniliform band ca 2/5 as long as the tube and ca 2/5 from the base in flowers with only anthers exserted or lower 3/8-7/16 glabrous and upper 9/16-5/8 sericeous, moniliform in flowers with only the stigma exserted or both anthers and stigma exserted, the lobes ovate or oblong or triangular, acute or broadly acute at apex, 0.8-2.1 x 0.5-1.2 mm, glabrous outside; stamens with the filaments 0.1-1.3 mm long, glabrous or sometimes minutely puberulent, the anthers 0.3-1.2 mm long, glabrous; style 1-6.5 mm long, glabrous or sometimes sparsely and minutely puberulent. Fruit with the emargination 0.2-0.3 mm, subpedicellate with the pedicels 0.2-0.3 mm long, glabrous, the mericarps broadly elliptic or rarely elliptic in outline, 1-1.6 x 0.7-1.3 mm, 0.5-0.6 mm thick, glabrous or puberulous or with a few scattered long curly hairs.

  • Discussion

    23. Declieuxia dusenii Standley, Publ. Field Columbian Mus., Bot. Ser. 8(5): 369, 1931. Type: Brazil, Paraná, Serrinha, 7 Dec 1908, Dusén 7301 (holotype S; isotypes F, G, GH, LE, MO, NY). It is difficult to determine the possible breeding system of Declieuxia dusenii from the herbarium specimens. There are three observable flower types: 1) with both the anthers and stigma exserted, 2) with only the anthers exserted, and 3) with only the stigma exserted. The flowers with both anthers and stigma exserted seem to have shorter corolla tubes, while those with only the anthers exserted have a different interior pubescence of the corolla tube, with a centrally located sericeous, moniliform band rather than the upper half of the tube sericeous, moniliform as in flowers with only the stigma or both the anthers and the stigma exserted. Some characters of D. dusenii are correlated with its north-south distribution. Those specimens from Paraná and São Paulo have fewer pairs of lateral veins, less pubescence, and more of the enlarged stipules than those from Santa Catarina. Two specimens from Santa Catarina, Reitz 5415 and 5499, have the immature portions of the inflorescence villous. As the inflorescences mature and enlarge, this condition results in the distribution of very scattered long curly hairs on the various parts of the inflorescence. Declieuxia dusenii is related to both D. tenuiflora and D. diantheroides (refer to the discussion of D. diantheroides). It differs from D. tenuiflora by greater regularity of internode length, smaller inflorescences, and normally larger flowers with nonpapillate hypanthia, and apparently occupies an intermediate position between D. diantheroides and D. tenuiflora.

  • Distribution

    Distribution. Known from northeastern Santa Catarina, eastern Paraná, and Campos do Jordão in São Paulo. Map 17.

    Brazil South America|