Actinocephalus giuliettiae Sano, 2011

Echternacht, Livia, Trovó, Marcelo & Sano, Paulo Takeo, 2011, Two new species of Actinocephalus (Eriocaulaceae) from Minas Gerais, Brazil, Phytotaxa 27, pp. 26-36 : 31-35

Actinocephalus giuliettiae Sano , sp. nov. ( Figs. 4 , 5 )

Ab Actinocephalo stereophyllo foliis rosulae majoribus (usque ad 10.0 cm × 5.5 cm) et cum apicibus acutis (non mucronulatis), ramus elongatis pluribus (usque ad 15 × 5), spathis apicibus obliquus (non truncatis) et apicibus bractearum involucralium obtusis (non acutis nec apiculatis) differt.

Type: — BRAZIL. Minas Gerais: Itabirito, Serra de Capanema , Mina de Capanema , no alto da serra, 1726 m, 20 o 13’09”S, 43 o 34’41”W, 12 March 2009, L . Echternacht , F. F . do Carmo & I. C . de Campos 1944 (holotype SPF, isotypes BHCB, P) .

Perennial herbs, 40–80 cm tall. Rhizome 1–3 cm long. Rosette bearing several axillary elongated branches, which bears the paraclades. Leaves rosulate, flat, patent, glaucescent, linear to lanceolate, 3–10 × 0.2–0.5 cm, glabrescent on both surfaces, slightly ciliated with short (ca. 0.5 mm) and long (ca. 3.5 mm) simple trichomes, apex acute, bearded in the young leaves, then glabrescent. Elongated branches indeterminate, 3–15 per rhizome, erect to patent, unramified, except for the paraclades, 35–60 × 0.3–0.6 cm, with bracts deciduous at the base and persistent at the middle and at the apex; elongate branch leaves densely spirally inserted, flat, patent, lanceolate, 2–5 × 0.2–0.5 cm, glabrescent on both surfaces, densely ciliated, especially at the base, with short and long simple trichomes, base semiamplexicaul, apex acute. Paraclades axillary, sub-opposite, unramified, 2.0–4.0 × 0.2 cm, pubescent; paracladial bracts distributed along the paraclade, subtending the umbel of capitules and also inside the umbel, delimitating groups of scapes, flat, patent, lanceolate, 1.3–2.0 × 0.3– 0.2 cm, adaxial surface glabrescent, abaxial surface pubescent to glabrescent, base semiamplexicaul, apex acute, ciliated with short and long simple trichomes. Spathes 0.8–1.3 cm long, pubescent to glabrescent, apex acute, ciliated and membranaceous. Scapes 40–50 per paraclade, 2.5–4.0 cm long, pubescent with patent trichomes, glabrescent when senescent; capitula 2.5–5.5 mm diam., hemispheric; involucral bracts brown, broadly ovate to elliptic, 1.0–2.0 mm long, pubescent abaxially, glabrous adaxially, apex obtuse, ciliated; receptacle hemispheric, pubescent. Flowers 3-merous, ca. 30 per capitula, half staminates, half pistilates; floral bracts castaneous, oblong, concave, ca. 2 mm long, pilose abaxially near the apex, apex obtuse and ciliate. Staminate flowers ca. 2 mm; pedicel ca. 0.3 mm long, with long trichomes; sepals castaneous to brown, fused at the base, broadly obovate, concave, ca. 1.5 mm long, pilose abaxially near the apex, apex round to mucronate, ciliate; corolla tubular, fleshy at the base, membranaceous and hyaline at the apex, ca. 1.5 mm long, 3-lobed, pilose adaxially at both apex sides, apex acute, glabrate; stamens ca. 2 mm long; pistillodes 3, papillose and pigmented. Pistillate flowers ca. 2.5 mm, sessile; sepals castaneous, obovate, concave, ca. 2.5 mm, pilose abaxially near the apex, apex obtuse to cuspidate, ciliate; petals lightly pigmented at the base, cream toward the apex, oblong, ca. 2.5 mm long, glabrous, apex obtuse, membranaceous and hyaline, ciliated at both sides but glabrous at the apex; gynoecium ca. 2.5 mm long, stigmatic branches completely fused, twice as long as the nectariferous branches; staminodes 3, scale-like. Fruit a loculicidal capsule.

Distribution and ecology: — Actinocephalus giuliettiae is terrestrial and occurs in open areas, growing over rocky quartzitic to ferruginous soils in the southern Espinhaço Range, in a mountain complex known as ‘Quadrilátero Ferrífero’ (Ferriferous Quadrangle), in the state of Minas Gerais, Brazil ( Fig. 3 ). The species is known exclusively from the Serra do Capanema, in the Itabirito municipality, with one single population composed of less than 20 individuals.

IUCN Red List category:—The single population known for Actinocephalus giuliettiae occurs on a mining property predicted to be exploited in the near future. Therefore, according to the IUCN (2008) criteria B2a and C2ai, this species should be classified as critically endangered (CE).

Etymology:—This species is dedicated to Dr. Ana Maria Giulietti Harley. Her passionate work produced numerous branches and countless fruits, as she guided tens of Brazilian taxonomists. She is a pioneer in the studies of Eriocaulaceae systematics in Brazil and inspired all of us with her contributions to the knowledge of the family.

Notes:— Actinocephalus giuliettiae possesses a rhizome that gives rise to rosettes and lateral elongated branches ramifying into paraclades. In Actinocephalus , only two other species share a similar architectural pattern, A. falcifolius (Koern.) Sano (2004: 102) and A. stereophyllus (Ruhland) Sano (2004: 105) , and which is described by Oriani et al. (2008) as pattern III. Actinocephalus giuliettiae differs from A. stereophyllus and A. falcifolius by its more numerous elongated branches per rosette, with bracts persistent at the middle and apex, longer scapes, with patent trichomes in youth, and petals of the pistillate flowers with glabrous apex. The presence of paracladial bracts inside the umbel of capitula has never been described for Actinocephalus , and might also be considered a diagnostic character for A. giuliettiae . There should be further investigation, however, to confirm whether A. stereophyllus , A. falcifolius or other species in the genus do not possess this character as well.

Actinocephalus stereophyllus is the species most similar to A. giuliettiae . Both have elongated branches similar in size, leaves of elongated branches are similar in shape and size, paraclades similar in size and in number of scapes, and spathes similar in size. In addition, the paraclades of A. stereophyllus usually are alternate, but they may be sub-opposite, as in A. giuliettiae . Actinocephalus giuliettiae differs from A. stereophyllus by its rosette leaves (up to 10.0 cm vs. 5.5 cm) with acute apices (vs. mucronulate), spathe apices oblique (vs. truncate) and involucral bracts with obtuse apices (vs. acute to apiculate). Actinocephalus stereophyllus occurs in campos rupestres on the Diamantina Plateau (Minas Gerais), in Diamantina municipality ( Sano 2004), so that both species occur allopatrically.

Actinocephalus falcifolius is also very similar to A. giuliettiae . Both species have rosette leaves of equal size and pilosity and elongated branches of similar size. However, A. giuliettiae possesses erect rosette leaves (vs. falciform), elongated non ramified (vs. ramified) branches, sub-opposite (vs. alternate) paraclades, erect to ascendant (vs. sinuate to arched), longer branch leaves (2.0–5.0 cm vs. 1.5–2.5 cm) and erect (vs. falciform), erect paraclades (vs. arched), paracladial bracts ciliated all along the margin with long trichomes (vs. ciliated only at the base) and longer scapes (up to 4.0 cm vs. 2.5 cm). Actinocephalus falciformis also occurs in the Iron Quadrangle and several populations are known to occur in the municipalities of Ouro Preto, Lavras Novas and Itabirito ( Sano 1999). It was not found in the Serra de Capanema and both species are thus currently occurring allopatrically.

Figures

FIGURE 3. Distribution map of Actinocephalus delicatus (black squares) and Actinocephalus giuliettiae (black stars).

FIGURE 4. Actinocephalus giuliettiae. A. Habit. B. Capitulum. C. Involucral bract abaxially. D. Floral bract of the staminate flower abaxially. E. Staminate flower. F. Staminate flower with all sepals one petal and one stamen removed. G. Pistillate flower. H. Petal of the pistillate flower showing the membranaceous, hyaline and glabrous apex I. Gynoecium. (Drawn from the holotype).

FIGURE 5. Photographs of Actinocephalus giuliettiae. A. Habit. B, C. Elongated branches, inflorescences and capitula. D. Rosette and elongated branches. E. Details of the inflorescence and capitula. F. Habitat in the Serra do Capanema. (Photos: Livia Echternacht).