Monographs Details: Declieuxia tenuiflora (Willd. ex Roem. & Schult.) Steyerm. & J.H.Kirkbr.
Authority: Kirkbride, Joseph H., Jr. 1976. A revision of the genus Declieuxia (Rubiaceae). Mem. New York Bot. Gard. 28 (4): 1-87.
Description:Species Description - Shrub 12-75 cm tall with several erect to spreading branched stems, the stems terete and glabrous to sparsely puberulous, the internodes 0.4-9(-11) cm long, basally short, increasing in length apically to very long. Stipules unidentate or rarely unequally bidentate or tridentate, the lobes linear-subulate with a triangular base, terminating in a conical gland, glabrous to puberulous, with 1-3 glands on each side of the stipule, the longest lobe 1 -5(-5.3) mm long, the laterals when present 2-4 times shorter than the longer lobe, very rarely the basal stipules foliar, 5-13 X 0.5 mm, narrowly elliptic, acute at apex, decurrent. Leaves opposite, often with smaller axial leaves, petiolate, the petiole winged, 1.5-11(-15) mm long and puberulous or rarely glabrous to glabrate; blade chartaceous, narrowly elliptic to rarely elliptic or rarely ovate to narrowly ovate, acute to narrowly acute or sometimes subacuminate at apex, attenuate at base, (0.8-) 1.1-4.4(-7) x (0.1-)0.4-1.5(-2.6) cm, (2.5-)2.9-3.5 or very rarely 11-23 times longer than wide, venation pinnate with 3-8(-10) arcuate anastomosing lateral veins on each side, the prominulous midrib, faintly prominulous lateral veins, and intercostal areas above glabrous to puberulous, the prominent midrib, prominulous lateral veins, and intercostal areas beneath glabrous to puberulous, the tertiary venation closed reticulate. Inflorescences numerous axillary and terminal modified cymes, pedunculate, 2.5-15 x (0.5-)2-20 cm, with 15-200 flowers, dichotomously or umbellately branched into 2-8 axes or rarely unbranched, the axes terete, 1-14 cm long, glabrous to sparsely puberulous; peduncle terete, 0.3-6.5 cm long, glabrous or glabrate to sparsely puberulous, with 2 bracts at apex resembling dichasial bracts or larger, the enlarged bracts narrowly elliptic or linear, acute at apex, cuneate at base, (2.2-)3.5-8.5 x 0.3-1.5 mm, glabrous or sparsely puberulous and occasionally ciliate. Flowers possibly protandrous, sessile to subpedicellate with the pedicels terete, 0.1-0.5 mm long, glabrous or sparsely puberulous, dichasial bracts narrowly oblong to linear-subulate, acute to broadly acute at apex, 0.7-2 x 0.1-0.5 mm, glabrous; hypanthium transversely broadly to transversely elliptic in outline, 0.4-0.8 x 0.4-0.9 mm, minutely and densely papillate; calyx lobes oblong or triangular or elliptic, acute to broadly acute or obtuse at apex, 0.2-0.4 x 0.1-0.3 mm, glabrous; corolla blue or white, funnelform, the tube 1.5-2.5 mm long, orifice 0.9-1.4 mm in diam, 0.3-0.5 mm at base, exterior glabrous, interior with a moderately sericeous, moniliform band ca 2/5 as long as the tube ca 2/5 from the base, the lobes oblong to ovate or broadly elliptic, broadly acute at apex, 0.7-1.3 X 0.5-0.9 mm, glabrous outside; stamens with the filaments 0.1-0.8 mm long, glabrous, the anthers 0.4-0.9 mm long, glabrous; style 1-3 mm long, glabrous. Fruit with the emargination 0.2-0.6 mm, sessile to subpedicellate, the pedicels 0.1-0.5 mm long, glabrous or sparsely puberulous, the mericarps broadly elliptic to circular in outline, 0.9-2.3 X 1.4-2.1 mm, 0.2-1.1 mm thick, moderately papillate.
Discussion:24. Declieuxia tenuiflora (Willdenow ex Roemer 8c Schultes) Steyermark & Kirkbride, Mem. New York Bot. Gard. 23: 399. 1972.
Toumefortia tenuiflora Willdenow ex Roemer 8c Schultes, Syst. 4: 540, 1819.
Knoxia brasiliensis Sprengel, Syst. 1: 406, 1824.
Declieuxia herbácea Chamisso 8c Schlechtendal, Linnaea 4(1): 11, 1829.
Declieuxia brasiliensis (Sprengel) Müller Argoviensis, Flora 59(28): 434, 1876. Type. Brasilia (fide Müller Argoviensis, 1881, prope Rio de Janeiro), Sello 1267 (lectotype COI, isotype COI).
Type: Venezuela, Sucre, Cumaná, Humboldt sn (holotype B).
Declieuxia tenuiflora is a cohesive species with the exception of one collection, Glaziou 13968. In this gathering, the leaves are very narrow so that the ratio of length to width is very high. In all other aspects, it falls within the normal range of variation for the species.
In the herbarium collections, the flowers seem to fall into three categories: 1) both anthers and stigma included, 2) only the anthers exserted, and 3) both the anthers and stigma exserted. This would seem to point to the possibility of protandry in this species, assuming that the maturity of these organs is indicated by the degree to which they are exserted.
This species exhibits a long disjunction, ca 2000 km, in its distribution which is very unusual in Declieuxia. There seem to be no character correlations which coincide with the distributional pattern. The same type of variation, that is in leaf size, amount of pubescence, and other characters, occurs in both areas of distribution of this species.
In the vicinity of Rio de Janeiro, D. tenuiflora inhabits a distinctive vegetational zone, restinga, on the recent sandy alluvial plain behind the beach, and appears to be a normal constituent of this vegetation type. On Cerro Altamira, it is an adventitive occurring on the edges of recent mining operations which removed all vegetative cover. The extensive savannas at the base of the mountain apparently do not support D. tenuiflora. Field observations would indicate that it is a faculatative ruderal under some circumstances.
Declieuxia tenuiflora is related to D. dusenii from which it can be distinguished by gradually increasing length of the internodes, that is from basally short to apically long, larger inflorescences, and smaller flowers with papillate hypanthia.
Distribution:Brazil South America
| Venezuela South America