Monographs Details: Henriquezia nitida var. macrophylla (Ducke) 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:Distribution and Ecology - Distribution. State of Amazonas, Brazil, along tributaries (Igana, Curicuriary, and Vaupes) of the Rio Negro. BRAZIL. Amazonas: ad ripas fluminis Curicuriary affluentes Rio Negro superioris; 28 Nov 1929, A. Ducke 22815 (holotype Rio, isotype US); Rio Curicuriary acima das cachoerias, margem; arvore pequefia; flores roses; 29 Nov 1936, Ducke 293 ( N Y ) ; Rio Igana, Masarico; arvore de 15-20 mts.; madeira dura; flores roseo-avermelhadas; 22 Oct 1947, J. Murca Pires 699 (2 sheets, NY); Rio Issana, Tunui; common along rocky banks; Oct 1947, Schidtes d; Pires 8967 (2 sheets, F); Igarape Piaiauara, Rio Curicuriari; tree about 40 ft high; bark shaggy, grey; wood relatively hard, white; 26-27 Apr 1948, Schultes & Lopez 9857 (F); Igarape da Chuva, Taracua, Rio Vaupes, between Ipanore and confluence with Rio Negro, 12 Nov 1947, Schultes & Pires 9061 (US).

Discussion:

Henriquezia macropTiylla Ducke, Notiz. Bot. Gart. Berl. 11: 475. 1932; Arch. Jard. Bot. Rio de Janeiro 6: 92. 1933.

The isotype of Henriquezia macrophylla Ducke (Ducke 22815) has the leaves rounded and only slightly mueronate at the apex, and matches in size and shape some of the larger ones encountered in H . nitida var. nitida, such as in the collection of Maguire, Wurdack, d; Bunting 36640. However, the lateral nerves of the leaf-blades of the isotype specimen are fewer and more widely separated. A topotype of H. macrophylla (Ducke 293), identified by Ducke as H . macrophylla, shows the leaf-blades more acutely obtuse or acutish, as do the other collections (except Schultes & Pires 9061). The isotype material may be interpreted as the less common variant of H . macrophylla having a more rounded apex of the leaf-blade.

When Ducke described H. macrophylla, its affinities were stated to be with H. obovata Spruce ex Benth. and H . verticillata Spruce ex Benth. Judging, however, by the persistent stipules, leaf shape, and nervation, as well as prominent, imbricate calyx-lobes divided all the way to their base, i.e., to the summit of the ovary, it is apparent that the true affinities of this taxon lie with H . nitida Spruce ex Benth. var. nitida. The main points of variance shown from H. nitida var. nitida by H. macrophylla are the generally acutish or acutely pointed leaf-blades (although rounded to broadly obtuse in the type collection of H. macrophylla), generally fewer pairs of lateral nerves more widely spaced, and generally a solitary petiolar gland.

The lateral nerves on the lower surface are of the slightly elevated type encountered in H. nitida var. nitida rather than of the prominently elevated type present in H. verticillata. Those on the upper surface of H. verticillata are prominently sulcate, whereas in H. nitida var. nitida and H. macrophylla they are merely impressed or even slightly elevated. Although the apex of the leafblades in H. nitida var. nitida are chiefly rounded or subtruncate, some of them occasionally are somewhat acutely obtuse, thereby exhibiting a transition to the generally acutish or acutely obtuse type characteristic of H. macrophylla. In most of the collections examined of H . nitida var. nitida, generally two petiolar glands are present, whereas only one is usually present in H. macrophylla. However, only one may be found in some specimens of H . nitida var. nitida, as in Maguire, Wurdack, & Bunting 36640, again indicating some variability in this character between the two taxa. In Pires 699 the calyx-lobes are more conspicuously caudate or long-acuminate with tips 3-4 mm long instead of 1-2.5 mm long and less slender as in Ducke 293.

In view of the variations indicated above and intergradation of the various characters used for separation of the taxa, H . macrophylla is here considered as a variety within the H . nitida complex rather than as a distinct species.

Distribution:Brazil South America|