Paepalanthus scleranthus Ruhland, 1903

Andrade, Maria José Gomes De, Trovó, Marcelo, Rocha, Lamarck & Giulietti, Ana Maria, 2022, Paepalanthus (Eriocaulaceae) without scapes and spathes, a survey with the description of a new species, Phytotaxa 560 (2), pp. 135-152 : 147

4. Paepalanthus scleranthus Ruhland in Engler, Pflanzenr. IV.30 (Heft 13): 200. tab. 28, 1903.

Lectotype (here designated):— BRAZIL. Minas Gerais: Perpetua près Diamantina , entre les rochers, 11 April 1892, A.F.M. Glaziou 19990 ( B [10_0247678]! , isolectotypes BR [0000008619495]!, C [10011014]!, G [00192125]!, K [000640072]!, LE [00001220]!, P [00716724]!, P [00716725]!) .

( Figures 2F , 3 , 4 Q-S, 6I-N).

Ruhland (1903) described Paepalanthus scleranthus based on the specimens Schwacke 11987, Ule 2714, Ule 2717 and Glaziou 19990, collected in Minas Gerais and distributed throughout many herbaria. According to the ICN ( Turland et al. 2018) and the type clarifications provided by McNeill (2014), a lectotype must be selected. Moldenke (1976a) argued that the specimen Glaziou 19990 deposited in B was the most relevant specimen used for the species description but referred all specimens as cotypes. We agree with Moldenke’s (1976a) interpretation, as among the original material, the specimen Glaziou 19990 at B perfectly matches the original description and plate and contains the original handwriting and line drawings provided by Willy Ruhland himself. It is therefore designated here as the lectotype.

Paepalanthus scleranthus ( Figure 2F ) is restricted to the sandy soils of the campo rupestre from the Espinhaço Range in Bahia and Minas Gerais, and it is sympatric in some areas with P. leucocephalus ( Figure 3 ). According to Ruhland (1903), it is mainly differentiated from P. leucocephalus by the blackish capitula (vs. whitish), besides a few floral variations explored in Table 2 and Figures 6 A–N . Although in some specimens the capitulum colour is clearly distinctive, in field observations and some herbarium specimens (e.g., the lectotype housed at C) the difference may be misleading. Moldenke (1976a) had previously expressed doubts on maintaining these two taxa segregated, especially regarding the type specimens, gathered in the same area.

Based on our field observation and herbarium analysis, we decided to keep Paepalanthus scleranthus and P. leucocephalus as distinct units as detailed in the Table 2 and Figures 2 , 4 , 6 . The difficult in differentiating both species is mainly regarding the populations from the Diamantina Plateau (where the types came from), and a few other localities where both species are frequently found growing together. The capitulum colour variation may represent a phenological and/or ecological condition, but yet no individual presenting capitula with intermediate color or with both capitula colors was recorded. Herbarium specimens with some individuals presenting whitish capitula and other presenting blackish capitula may represent problematic field collections (a common situation in small Eriocaulaceae ), but not necessarily reflect the species delimitation. We also may keep in mind that hybrids in Eriocaulaceae may be more frequent than we expected, as exemplified in Hensold (1988). Paepalanthus being a group of recent diversification ( Vasconcelos et al. 2020) and with the relevance of the capitulum color to the reproductive biology of Eriocaulaceae ( Martins Junior et al. 2022) , further investigations along the entire species distribution, including population genetics, reproductive biology, and morphology would be of benefit to precisely establish the species circumscription.

Additional selected material examined:— BRAZIL. Bahia: Rio de Contas, Serra Marsalina , 6 October 2006, R. M . Harley et al. 55538a ( HUEFS); Rio de Contas, Serra Marsalina , 6 October 2006, R. M . Harley et al. 55538b ( HUEFS) . Minas Gerais: Catas Altas, Serra do Caraça, Ule 2717 ( B, HBG, NY); Diamantina, Biribiri , 25 March 1984, A. M . Giulietti et al. CFCR 4290 ; Ouro Preto, Ule 2714 ( B, HBG, R); Serra das Camarinhas, Schwacke 11987 ( B, BHCB); Tiradentes , Serra de São José , 21°05’S, 44°10’W, s.d., R . Alves 4015 ( RB) .

Figures

FIGURE 2. Life-forms and inflorescences in Paepalanthus species without scape. A–B. Paepalanthus leucocephalus growing in the Chapada Diamantina, BA. C–E. P. paganuccii. C. Population growing in Tocantins (Harley 56669) on sandy soil. D. Rupiculous individual growing on sandstone. E. Detail of the capitulum. F. P. scleranthus, growing in Diamantina, MG, showing the black capitula. G. P. sessiliflorus growing in campo rupestre in Pico das Almas, BA. Scale bar: 5 mm. (photo credits: A–B. C.N. Fraga, C–E, G. R.M. Harley, F. M. Trovó).

FIGURE 3. Geographical distribution of Paepalanthus species without scape. Red-orange symbols = Paepalanthus ser. Leptocephali; Blue-green symbols = P. subg. Thelxinoë.

FIGURE 6. SEM micrographs. A–H: Paepalanthus leucocephalus. A. leaf with two types of trichomes: filamentous and malpighiaceous (2 armed) trichomes. B. staminate flower showing bract, calyx, anthophore, corolla and anther. C. pistillate flower showing bract, calyx with two concave sepals and one petal and part of ovary. D. pistillate flower showing one sepal, one petal and gynoecium with style with stigmate branch, lacking nectariferous branch. E. pistillate flower showing detail of the petal and gynoecium.F. detail of the external ovary surface. G. mature seed, seed coat with a reticulate pattern. H. detail of the seed coat showing the cells 4-5 walled. I–N: Paepalanthus scleranthus. I. leaf with two types of trichomes: filamentous and malpighiaceous (2 armed) trichomes. J. adaxial leaf surface showing detail of the filamentous and malpighiaceous trichomes. K. pistillate flower showing bract, one sepal, one petal and gynoecium. L. staminate flower showing calyx, anthophore, corolla and anther. M. pistillate open flower showing two sepals bigger than the two petals and gynoecium with stigmatic branch, lacking nectariferous branches. N. pistillate closed flower showing two concave sepals involving the corolla. (A–C. Andrade 589, D–F. Andrade 625, G–H: Andrade 620, I–J, M. Harley 55538a, K–L, N. Harley 55538b).

FIGURE4.MorphologyofplantandflowersinPaepalanthuswithoutscape.A–K:Paepalanthuspaganuccii.A.habit.B.leaf.C.capitulum. D. involucral bract of the outer series. E. involucral bract of the inner series. F. open staminate flower showing calyx, anthophore, corolla, androecium and floral bract. G. closed staminate flower showing pedicel, calyx and corolla trichomes. H. open pistillate flower showing calyx, corolla, gynoecium and floral bract. I. sepal. J. petal. K. developing fruit with two petals. L–M: Paepalanthus sessiliflorus var. sessiliflorus. L. open staminate flower showing calyx, anthophore, corolla, androecium and floral bract. M. open pistillate flower showing calyx, corolla, gynoecium and floral bract. N–P: Paepalanthus leucocephalus. N. open staminate flower showing calyx, anthophore, corolla, androecium and floral bract. O. closed pistillate flower showing calyx, corolla and floral bract apex. P. open pistillate flower showing calyx, corolla and gynoecium. Q–S: Paepalanthus scleranthus. Q. open staminate flower showing calyx, anthophore, corolla, androecium and floral bract. R. closed pistillate flower showing calyx, corolla and floral bract apex. S. open pistillate flower showing calyx, corolla and gynoecium [A–K. Queiroz 10917, holotype of P. paganuccii (HUEFS), L–M. Andrade 623 (HUEFS), N–P. Andrade 549 (HUEFS), Q–S. Alves 4015 (RB), drawings by AMG inked in by Carla Lima].