Monographs Details: Henriquezia nitida var. oblonga (Spruce ex Benth.) Steyerm.
Authority: Maguire, Bassett & Wurdack, John J. 1964. The botany of the Guayana Highland--Part V. Mem. New York Bot. Gard. 10: 1-278.
Family:Rubiaceae
Description:Latin Diagnosis - Arbor 4-5 m alta; foliis 3-4-natiin verticillatis anguste oblongis vel apiculatis, laminis 9-17.5 cm longis 2.5-5.5 cm latis subtus pallidioribus, supra nervis lateralibus impressis subtus vix prominulis vel subobsoletis utroque latere 12-15; petiolis 9-30 mm longis glabris vel minute parce puberulentibus; petioli duobus glandulis orbicularibus vel ovalibus 0.7-1 mm altis 0.7 mm latis ventraliter insertis; stipulis lanceolatis vel lanceolato-linearibus acuminatis 12-17 mm longis 1.2-2.5 mm latis dense tomentellis; inflorescentiis 9-15-floris 4.5-9 cm longis (altis) 6.5-15 cm latis, ramis lateralibus 1.5-2.2 cm longis, pedicellis 4-12 mm longis velutino-tomentosis pilis fulvis dense vestitis; calyce 15-22 mm longo, lobis 4 inaequalibus ovatis vel elliptico-ovatis acutis vel acuminatis duobus majoribus latioribus magis acuminatis 12-17 mm longis 4.5-8 mm latis usque ad ovarium divisis; calycis tubo 3-4 mm longo 5 mm lato; corollis 40-55 mm longis late infundibuliformibus basi tubo 3.5-8 mm longo 4-5 mm lato extus dense sericeovelutinis intus infra zonam barbatam 4r-8 mm glabro vel papillato, supra tubum angustum subito ampliatis, limbo 21-30 mm longo superne 18-30 mm lato extus mollissime tomentuloso, lobis 5 late ovatis apice rotundatis 12-18 mm longis 10-19 mm latis extus tomentulosis intus glabris uno lobo basi puberulo excepto; staminibus inaequalibus duobus brevioribus, antheris 5-7 mm longis, filamentis 11-16 mm longis.

Distribution and Ecology - Distribution. Southwestern Venezuela, Territorio Federal Amazonas, along the Rio Atabapo and Cano Catua and tributaries. VENEZUELA. Amazonas: frequent on the Rio Atabapo, an affluent of the Orinoco near the mouth of the Casiquiare; small tree of about 18 ft in height, with spreading branches; Jun 1854, Spruce 3702 (photo NY); along Cano Catua at northwestern base of Cerro Yapacana; occasional; small or medium riverine tree; leaves 4 per node; buds pink; sepals pale tinged pink; corolla flushed pink with orange-red spots and median line within; alt. 125 m; 19 Nov 1953, Maguire, Wurdack, & Bunting 36557 (NY); Atabapo, cerca de la desembocadura del Rio Atacavi; 4 Sep 1960, Foldats 3706 (VEN).

Discussion:

Henriquezia oblonga Spruce ex Benth. Trans. Linn. Soc. 22: 297. 1859.

As the original description of H. oblonga was inadequately drawn from fruiting material, a more complete emended description, supplemented by flowering material, has been given above.

The Maguire, Wurdack, dc Bunting 36557 collection differs in several details from that of Foldats 3706 in having 4-verticillate leaves with much longer, more puberulent petioles 15-30 m m long, no apparent petiolar glands, larger corollas 48-55 mm long instead of 40-42 mm, and anthers 5 instead of 7 mm long. The larger corolla appears to be due to harder pressing. The longer, more puberulent petioles m ay prove at a future time to have taxonomic significance, but, at present writing, are being interpreted as within the limits of variability manifested by this taxon.

All the specimens examined of H. nitida show predominantly large oblong leaf-blades broadly rounded or subtruncate to broadly obtuse at apex, often retuse or mucronulate, and with the lateral nerves on the lower leaf-surface prominent or manifest. When Spruce described H. oblonga (loc. cit. 297), based on his number 3702 from the Rio Atabapo of southwestern Venezuela, he stated that it differed from H. nitida in having smaller leaf-blades with relatively longer petioles, and less shining leaf-blades, paler below and with the lateral nerves scarcely evident. He admitted, however, that his H. oblonga, collected only in the fruiting stage, might prove to be possibly a variety only of H. nitida, which he collected in the flowering state. Two recent collections, both in anthesis, which I have judged to be conspecific with H. oblonga, are Foldats 3706 from near the type locality of the Rio Atabapo station and Maguire, Wurdack, & Bunting 36557. Both collections show the smaller leaf-blades, paler beneath with the lateral nerves of the lower leaf surface scarcely developed and not obvious, and match the characters given in the original description as well as the photograph of the holotype from Kew Herbarium deposited in The New York Botanical Garden Herbarium. The leaves of the Foldats 3706 collection are 3-verticillate, those of the Maguire, Wurdack, & Bunting 36557 collection 4-verticillate. Apparently, 3-verticillate leaves are represented by the holotype specimen photographed at K.

Although it might appear that these smaller-leaved trees with the lateral nerves scarcely evident on the lower surface of the leaves represent a distinct species, intergradation occurs in leaf size between H. nitida and II. oblonga. No floral distinctions can be found between these two taxa, and they are, therefore, considered only as varieties differing in vegetative characters.