Jacaranda orinocensis Sandwith
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Authority
Maguire, Bassett & Wurdack, John J. 1958. The botany of the Guayana Highland--Part III. Mem. New York Bot. Gard. 10: 1-156.
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Family
Bignoniaceae
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Scientific Name
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Description
Latin Diagnosis - Sect. Monolobos DC, J. hesperiae Dugand atque J. caucanae Pittier ob calycem corollamque affinis ab ambabus habitu humili, foliorum pinnis necnon foliolis paucioribus, iiiflorescentia ramulos hornotinos terminante, ovario glabro differt. Frutex vel arbor parva, 3 mm altus; ramuli hornotini lenticellis cremeis notati, parce minute lepidoti, pilis perpaucis hyalinis minutis apice glanduliferis praediti, ceterum glaberrimi. Folia ramulorum inflorescentias gerentium imparibipinnata (rarius simpliciter imparipinnata, foliolis distincte petiolulatis), internodiis rhacheos 2-5 cm longis supra canaliculato-marginatis exalatis fere glabris, pinnis 3-9-jugis; foliola imparipinnatim 3-6-juga vel in pinnis imis suminisque 1-2-juga vel etiam solitaria, rhombeo-oblonga vel obovato-oblonga vel obovata, lateralia apice acuta vel obtusa usque rotundata cuspidatula basi cuneatim attenuata obliqua inaequilatera subsessilia vel plus minusve distincte (ad 5 mm)petiolulata, 0.5-3.5 cm longa, 0.3-1.6 cm lata, terminalia vulgo majora elliptica vel nonnunquam suborbiculari-elliptica utrinque acuta vel apice breviter acute acuminata vel rotundata, ad 3.5 cm longa, ad 2.5 cm lata, omnia chartacea, infra pallida glaucescentia, fere glabra sed supra secus nervos minute puberula atque subtus basin costae versus saepe pilosula, nervis venulisque supra planis vel impressis subtus prominulis. Folia ramulorum sterilium maxima, fere glabra, 40-45 cm longa, 30-40 cm lata, paribipinnata, internodiis rhacheos 4-6.5 cm longis subteretibus exalatis supra peranguste vix obvie nee profunde canaliculatis, pinnis 6-jugis; foliola imparipinnatim 3-9-juga, lateralia trapezoideooblonga apice acuta mucronata basi acuta cuneatim attenuata, subsessilia vel distincte ad 3 mm petiolulata, 2-4 cm longa, 1-1.8 cm lata, terminalia lanceolatoelliptica apice conspicue acuminata basi longe attenuata ad 5.5 cm longa ac ad 2 cm lata, ceterum iis sub inflorescentiis dispositis similia sed rigidiora. Inflorrscentia apice ramulorum hornotinorum terminalis, in exemplis visis 5-12 cm longa, 6-9 lata, velut ramuli minute parcissime lepidota ceterum glabra; bracteae primariae foliaceae anguste elliptico-lanceolatae vel lineari-spathulatae petiolatae, ad 1.3 cm longae, 1.5-3 mm latae, superiores gradatim breviores; pedicelli ad 5 mm longi, saepe cernui. Calyx saltern ad medium vulgo ultra medium divisus, extra parce inaequaliter lepidotus ceterum glaber; lobi oblongi, spathulato-oblongi vel triangulari-lanceolati, apiee acuti vel obtusi, 3.5-5 mm longi, 1.5-2 mm lati, nonnunquam breviores deltoideo-triangulares acuti 1-1.5 mm tantum longi. Corolla purpurea, ad 3.5 cm longa, saepius curvata; tubus basi more generis circa ovarium inflatus, turn breviter anguste cylindricus ac extra pilis crebris papilliformibus rectis hyalinis apice glanduliferis praeditus, turn campanulato-infundibuliformis ac apice circiter 1.5 cm latus extra glabrescens ac oeulo nudo glaber, intus zona lata pilorum sub staminum insertione excepta glaber; limbus expansus circiter 2.3 cm diametro, lobis circiter ad 8 mm longis et 1.2 cm latis longe conspicue ciliatis. Stamina circiter 8 mm supra tubi basin inserta, longiora 1.3-2 cm breviora .1.1-1.7 cm longa; filamenta basin versus pilis brevibus rectis hyalinis glanduliferis iis zonae sub insertione staminum similibus praedita; antherarum theca fertilis 2-2.2 mm longa, sterilis ad 0.75 mm longa; staminodium 2.7-3 cm longum, inferne glabrum, prope medium et apicem claviformem versus pilis longis flexuosis apice glanduliferis barbato-villosum, dimidio superiore glabrescens sed linea glandularum sessilium vel subsessilium praeditum. Discus pulvinaris, ad 1.2 mm altus, ovario multo latior. Ovarium ovoideum, glabrum, vix 1.5 mm diametro; stylus glaber, stigmatibus inclusis ad 2.5 cm longus. Fructus valde immaturus tantum visus, apice rotundatus.
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Discussion
Type: VENEZUELA: Estado Bolivar, Rio Pargueni, Rio Orinoco, frequent at river edges 1-10 km above mouth, alt. 90 m, tree 3 m, fls. purple, Dec 10, 1955. J. J. Wurdaek and J. V. Monachino 39769 (holotype NY, isotype K).
The large leaves of sterile shoots, which I have described above and which, it is interesting to note, retain the small number of pinnae, were taken from a single example of the "population" from which the flowering specimens of no. 39769 were collected. Dr. Wurdaek writes that "the plants of 39769 were very abundant along- the Pargueni, but were flowering sporadically, so the collection number probably represents at least 6 different plants."
The two collections are not uniform, no. 41365 showing leaves with more numerous pinnae and shorter calyx lobes than those of 39769, but I am confident that they represent a single entity which is of interest because of its apparent relationship in floral characters with two species, J. hesperia and J. caucana, and especially the former, with a very different distribution in Colombia (see Dugand, Mutisia 23: 1-11. 1954). The other somewhat similar species of sect. Monolobos, J. obtusifolia II. & B. which, with its vars. obtusifolia and rhombifolia, is well known in the Orinoco basin, is at once distinguished from J. orinocensis by the numerous leaflets of the usually more numerous pinnae, by the inflorescence arising from old wood, the shortly deltoid teeth of the calyx, and the absence of glandular hairs on the outside of the corolla tube towards its base.