Dyckia mirandiana Leme & Z. J. G. Miranda, sp. nov. Type: Goias, Alto Paraiso de Goias, ca. 20 km from the city toward Teresina de Goias, km 197 road GO 118, way to Poco Encantado, ca. 1,400 m elev., 24 July 2004, Z. J. G. Miranda s. n., fl. cult. E. Leme 6380. Holotype, HB.
Inter generis species valde singularis, a speciebus omnibus foliis
distichis vel fere, laminis foliorum utrinque distincte nervatis,
marginibus sparse spinosis, inflorescentia curvata, breviore,
floribus manifeste odoratis, sepalis atrovinoso-purpureis, petalis
flavidis, apice obtusis apiculatisque vel subacutis, antheris basi
connatis et apice petalorum aequantibus differt.
Plant terrestrial, flowering 20-25 cm high. Leaves 10-15, distichously arranged or nearly so, coriaceous; sheaths distinctly broader than the blades, the older ones forming a subglobose base, 3.4- x 4-5 cm, suborbicular-ovate, dark castaneous, lepidote; blades sublinear-attenuate, distinctly U-canaliculate, suberect-arcuate, 25-40 cm long, ca. 1 cm wide near the base, green to reddish toward apex, opaque, inconspicuously white-lepidote abaxially with trichomes disposed along the intercostal zones and not obscuring the color of the blades, adaxially glabrescent toward the apex, distinctly nerved on both sides, apex long acuminate-caudate, pungent, margins glabrous, sparsely spinose, spines 0.5-1 mm long, ca. 15 mm apart from each other, uncinate, retrorse to antrorse, castaneous, glabrous. Scape lateral, erect except for the curved apex, ca. 8 cm long, 0.4-0.5 cm in diameter, glabrous, sulcate, dark purplish-wine to blackish; scape bracts erect, dark purplish wine, distinctly nerved, bearing a central protruded longitudinal nerve but not at all carinate, sparsely to densely white-lepidote toward the apex, narrowly triangular, long acuminate-caudate, 12-18 x 6-8 mm, exceeding to equaling the internodes, margins microscopically and densely denticulate. Inflorescence strongly curved, ca. 6.5 cm long, laxly (at base) to subdensely (at apex) flowered, rachis straight, margins angular, dark purplish-wine to blackish, glabrous, 2-2.5 mm in diameter; floral bracts subtriangular, acuminate, bearing a protruded central nerve but not at all carinate, nerved, dark purplish-wine, sparsely white-lepidote, membranaceous, 7-10 x 5-6 mm, suberect with the flowers, exceeding (basal ones) to slightly shorter than the sepals, margins inconspicuously denticulate to entire. Flowers ca. 9 in number, ca. 12 mm long with extended petals, suberect anthesis, producing a strong sweet fragrance, pedicels inconspicuous, stout, ca. 1.5 mm long, ca. 3 mm in diameter at apex; sepals symmetric, acuminate, convex, ecarinate but bearing a protruded central nerve mainly toward the apex, 6-6.5 x 3.5-4 mm, dark purplish-wine, glabrous, entire, bearing a protruded central nerve toward the apex but not at all carinate; petals symmetric, broadly obovate-spatulate from a narrower base, apex obtuse and apiculate to subacute, connate at base for ca. 1.5 mm in a common tube with the filaments, ca. 10 x 7.5mm, ecarinate, yellow, erect anthesis and forming a tubular corolla ca. 3 mm in diameter at apex; stamens about equaling the petals but distinctly exposed at the apex of the corolla at anthesis; filaments complanate, yellow, connate at base for 1.5-3 mm and free above, but arranged closely together and forming a cylindrical tube ca. 8 mm long; anthers narrowly subtriangular, ca. 2 mm long, base distinctly sagittate, apex acute, strongly recurved toward the apex, fixed at base, adnate to each other at base and free toward the apex, forming a stellate structure well visible at the apex of corolla, ca. 2.5 mm in diameter, bearing a central entrance-hole ca. 0.5 mm in diameter; pistil ca. 6 mm long, completely hidden by the filaments tube; stigma conduplicate-spiral, blades subentire, yellow; style ca. 1 mm long, yellowish; ovary ovate, ca. 4 mm long, ca. 2 mm in diameter, greenish. Capsules unknown.
Paratype: Goias, Alto Paraiso de Goias, km 196 road GO 118, toward Teresina de Goias, 13[degrees]55'41.4"S 47[degrees]25'59.4"W, 1,473 m elev., Z. J. G. Miranda s. n.. (CEN).
This new species can be distinguished from all known taxa due to an unusual combination of morphological features, like the distichous arranged leaves, leaf blades distinctly nerved on both sides with margins sparsely spinose, inflorescence curved and short, flowers strongly fragrant, sepals acuminate and dark purplish-wine, petals yellow with an obtuse and apiculate to subacute apex, forming a tubular corolla, and by the anthers basaly connate and equaling the petals.
The distichous leaf arrangement of Dyckia mirandiana resembles the rosette structure of D. estevesii Rauh (D. mirandiana never forms large clumps whereas D. estevesii does). However, because of completely distinct flower morphologies, these two species are not closely related. Conversly, whilst the leaf rosettes of D. mirandiana and D. horridula are not alike, these two species do have some common floristic characters such as the strong sweet fragrance and the yellow petals. Also, their filaments form a tubular structure, despite their being completely connate in D. horridula, that has a campanulate corolla, but only connate at base in D. mirandiana that shows in contrast a tubular corolla. Finally, they share the anthers basally connate to each other, forming a stellate structure in a top view, and bearing a small central entrance-hole to the internal chamber formed by the filaments, which hides the female organs. That stellate structure formed by the anthers obstructs almost completely the entrance of the tubular corolla of D. mirandiana and is well visible above it.
Dyckia mirandiana was found growing terrestrially, as a heliophyte, on an almost flat or slightly inclined terrain, with the sub-globose basal portion of the plants completely sunk in sandy soil accumulated among quartzitic outcrops in Campos Rupestres vegetation. The specimens were observed growing isolated or in small groups of about five or more individuals, with populations severely affected by the annual fires. In field conditions, the strong sweet fragrance produced by its flowers was more intensively perceived between 10:00 to 12:00 am.
The name chosen for this new species honors the bromeliad collector and writer Antonio Miranda from the University of Brasilia, DF, who is an enthusiast of the bromeliad study and conservation in the Cerrado ecosystem of the Brazilian Central Plateau.
Literature cited
Forzza, R. C. and B. R. Silva (2004). "A new species of Dyckia (Bromeliaceae from Rio de Janeiro State, Brazil." Novon 14(2): 168-170.
Leme, E. M. C. and J. A. Siqueira-Filho (2007). Taxonomy of the bromeliads of the Atlantic Forest fragments of Pernambuco and Alagoas. Fragments of the Atlantic Forest of Northeast Brazil, Biodiversity, Conservation and the Bromeliads. Siqueira-Filho and E. M. C. Leme. Rio de Janeiro, Andrea Jakobsson Estudio: 191-381.
Luther, H. (2006). An alphabetical list of bromeliad binomials 10th edition. Sarasota, FL, Bromeliad Society International.
Strehl, T. (1994). "Bromelias que passam parte do ano submersas." Bromelia 1(3): 19-21.
--(2005). "Novas especies de Bromeliaceae do Rio Grande do Sul, Brasil." VidAlia 2(2): 26-36.
Authors
E.M.C. Leme: Herbarium Bradeanum, Rio de Janeiro, Brazil. e-mail: leme@tj.rj.gov.br
J.G. Miranda: Embrapa Cerrados, BR 020, km 18, Planaltina, DF, Brazil, CP 08223, 73310-970. e-mail: zenilton@cpac.embrapa.br
Fonte: http://www.antoniomiranda.com.br/ensaios/dyckia_mirandiana.html
No comments:
Post a Comment