Syngonanthus cuyabensis (Bong.) Giul., Hensold & L.R. Parra, 2012

Giulietti, Ana Maria, Hensold, Nancy, Parra, Lara Regina, Andrade, Maria José Gomes De, Berg, Cassio Van Den & Harley, Raymond Mervyn, 2012, The synonymization of Philodice with Syngonanthus (Eriocaulaceae), Phytotaxa 60 (1), pp. 50-56 : 53-55

Syngonanthus cuyabensis (Bong.) Giul., Hensold & L.R. Parra , comb. nov.

Basionym: Eriocaulon cuyabense Bongard (1831: 634 , t. 10). Paepalanthus cuyabensis (Bong.) Kunth (1841: 520) . Philodice cuyabensis (Bong.) Koernicke (1863: 305) . Type:— Brazil. Mato Grosso: Cuiabá, April, Riedel 946 (holotype LE, isotypes B!, OXF!).

Synonyms:— Philodice hoffmannseggii Martius (1834: 26 , 29), syn. nov. TYPE:— Brazil. Pará : Sieber s.n. (holotype BR!, isotype B!) .

Philodice hoffmannseggii var. compacta Koernicke (1863: 306) , syn. nov. TYPE:— Brazil. Piauí: Oeiras, July 1839, Gardner 2749 bis (lectotype HAL! here selected, isolectotypes BM!, K! [2 exs.]). Koernicke (1863:303) reported that he saw the Gardner collections at W (now mostly destroyed) and in the herbarium Schlechtendal (now at HAL). So we choose to lectotypify P. var. compactus with the duplicate at HAL , which is visible online and was annotated by Koernicke.

Note:—Martius' description of Philodice and its solitary species, P. hoffmannseggii , were first published in the context of a condensed French translation of his more complete (1835) paper. Although Martius’ complete publication (1835) provided a full species description and illustration, the description of the monotypic genus in 1834, together with citation of a species name and type, suffices for valid publication of the species (ICBN [Vienna Code], Article 42, McNeill et al. 2006).

Koernicke (1863) distinguished the two species principally by the involucral bracts linear-lanceolate, green with white hyaline margins, slightly puberulous, rigid, and surpassing the flowers in P. hoffmannseggii , versus ovate or oblong-lanceolate, white-hyaline throughout, glabrous, membranous, and equalling the flowers in P. cuyabensis . He also noted a difference in shape of the staminate corolla lobes, with those of P. hoffmannseggii being acuminate, and those of P. cuyabensis being " obtusissimas retusas apiculatas." In addition, P. hoffmannseggii was described as having a more lax habit with flaccid leaves, and P. hoffmannseggii var. compacta and P. cuyabensis as being smaller, more erect plants with ascending leaves, and scapes barely surpassing the leaves. This treatment was accepted by Ruhland (1903).

Study of available material showed the following variation in characters:

1. Plant height varying from 12 to 15 cm [Sieber s.n. (OXF), Spruce 964 (K)] down to much smaller plants from 2 to 3.5cm [Riedel 946 (B, OXF), Huber 64 (NY, K), Ule 7666 (K), Giulietti 2483 (HUEFS)];

2. Leaves glabrous to slightly pubescent;

3. Scapes varying in length from 3 cm [Sieber s.n. (OXF)] to 0.3 cm [Riedel 946 (OXF)]. In several examples, scape length was observed to vary even in the same specimen, in Ule 7666 (K) from 0.3 to 0.8 cm; Spruce 964 (K) from 0.5 to 2.5 cm, and in Gardner 5243 (K) from 1 to 1.5 cm ( Fig. 1 A, I );

4. The involucral bracts vary from white-hyaline to green or castaneous with the margin sometimes paler or hyaline;

5. The involucral bracts usually display two series, with the outer smaller, varying from 1.5–1.8 mm in Riedel 946 to 3.5–4 mm long in Maas & Westra 4105 (K), either slightly smaller to equalling the length of the flowers in Riedel 946 and Gardner 2749 (K) or up to slightly longer to much longer than the flowers to 1.5 mm in Maas & Westra 4105 ( Fig. 1B . JK);

6. The capitula measure between 0.5 and 0.6 mm in diameter, bearing 6–10 staminate flowers and 7–11 pistillate flowers, about 1 mm long. The pistillate flowers are arranged, mixed with staminate flowers, on the periphery of the capitulum, with only staminate flowers in the centre;

7. The staminate flowers are long-pedicellate, with 3 sepals joined at the base; the corolla has three fused petals, ± fleshy, urceolate to infundibuliform, lobes acute to acuminate, usually with one lobe larger than the others; stamens 2, free from the corolla, stamen filament cylindrical, anther linear-oblong, more or less basifixed, bithecous, tetra- to bi-sporangiate, pistillode very small ( Fig. 1 C–E; L–N ).

- Stützel & Gansser (1995) mention that Philodice often has normal bithecous-tetrasporangiate anthers, but these sometimes become irregularly monothecous-bisporangiate due to lateral reduction.

- Examination of the staminate flower found in material of Ule 7666 (K) showed that the corolla has a very delicate zone between the petals in the basal region, but not in the median region, a character also found in the corolla of the pistillate flower ( Fig. 1 M–N ). According to Koernicke (1863: 289), in both Philodice and Paepalanthus subg. Carphocephalus (= Syngonanthus sect. Carphocephalus ) the petals of the staminate flower tend to separate into rhomboidal segments with age.

8. The pistillate flowers are shortly pedicellate, with 3 free sepals, concave, acute to acuminate; petals 3, fused in the mid-portion and free at the base and apex, acute to acuminate, usually one lobe larger than the others ( Fig.1F–H, O–P ).

In spite of the observed variation in some characters among the material examined, intermediate stages can always be found, justifying the recognition of only a single taxon.

Habitat:—The plants are annuals of low wet sandy open places, riverbanks, and often in standing water on disturbed ground. The lax habit described for P. hoffmannseggii versus the more compact habits of its variety and of P. cuyabensis probably correlate with soil moisture differences.

Distribution: —Currently, the species is known to occur in Northern South America ( Colombia, Venezuela, Guyana and Suriname) and in Brazil from Pará southward to Piauí, Ceará, Bahia, Minas Gerais, Goiás and Mato Grosso and extending to Bolivia ( Giulietti & Hensold 1990, Hensold 1999, Giulietti et al. 2009).

Figures

FIGURE 1. Syngonanthus cujabensis. A: Habit; B: Involucral bract from the inner series; C–E: Staminate flower; C: Pedicel, calyx and stamens exserted; D: Calyx opened to show the corolla and stamens; E: Corolla, front view, showing the stamens and pistillode; F–H: Pistillate flower; F: Sepals and apices of the petals; G: Calyx opened to show the corolla united in the median region and free at the base and apex; H: Gynoecium (A–H from Riedel 946); I: Detail of the inflorescence with the cauline leaves removed; J–K: Involucral bracts; J: Outer series; K: Inner series; L–N: Staminate flower; L: Complete flower with bract, calyx and corolla; (I–L from Maas & Westra 4105); M: Calyx opened to show the corolla with a more delicate zone; N. Calyx opened to show the areas of separation between the petals (M–N from Ule 7666); O–P: Pistillate flower; O: Complete flower with bract, calyx and corolla (from Maas & Westra 4105); P: Calyx with one of the sepals removed to show the corolla united in the median part and free at the base and apex (from A.C. Smith 2284). Drawn by Ana Maria Giulietti & Carla Lima.