Cyathea praecincta (Kunze) Domin, 1929

Cyathea praecincta (Kunze) Domin View in CoL

Cyathea praecincta (Kunze) Domin ( Domin 1929a: 263) View in CoL . – Alsophila praecincta Kunze ( Kunze 1839: 53) . – Alsophila submarginalis Domin ( Domin 1929c: 217) , nom. superfl. – Cyathea submarginalis (Domin) Domin ( Domin 1930: 163) View in CoL . – Trichipteris submarginalis (Domin) R.M.Tryon ( Tryon 1970: 46) View in CoL . – Trichipteris praecincta (Kunze) R.M.Tryon ( Tryon 1970: 46) View in CoL .

– Type: BRAZIL • Bahia; Ilheos; ca 14°10′ S, 53°05′ W; 1817–1820; C.F.P. Martius 391; lectotype: B [ B 20 0000200 ]!, chosen by Barrington 1978; GoogleMaps isolectotypes: B [ B 20 0000198 , B 20 0000199 , B 20 0000201 ]!, BR [ BR0000006987541 , labelled “ Ilheos, Luschnatt ”] image!, HAL [ HAL-0086574 ]!, K [ K000589886 ]!, L [ L.1284712 , L.1284714 ]!, LE [ LE00008123 ] image!, M!, MO [ MO-255859 ]!, NY [ 00148753 , fragment of B, 00148755, 00148756] image!, P [ P00631777 , P00631778 , P00631779 ]!. GoogleMaps

Etymology

The specific epithet translates as ʻwell girdledʼ, which may either refer to the tight, string-like arrangement of the sori or the many deep sinuses along each side of a pinnule.

Selected material studied

BRAZIL – Alagoas • Poço DʼAnta , ca 16–19 km NNW of Muricí by road, Mata de Muricí ; 9°14′ S, 35°53′ W; 550–600 m a.s.l.; 14 May 2001; W.W. Thomas 12419; MO, NY GoogleMaps . – Bahia • Arataca, Serra do Peito-de-Moça ; 15°12′10″ S, 39°24′29″ W; 900 m a.s.l.; 12 Aug. 2009; P.L.R. de Moraes, H. van der Werff, L. Daneu & R. Perdiz 2737; HUEFS, RB GoogleMaps • Camacã, RPPN Serra Bonita ; 28 Nov. 2014; P.L.R. de Moraes, H. van der Werff & L. Daneu 4254; HRCB • Almadina, Serra do Corcovado ; 13 Dec. 2014; P.L.R. de Moraes, H. van der Werff & L. Daneu 4553; HRCB • Belmonte, Fazenda Taquara ; 16 Feb. 2015; P.L.R. de Moraes, H. van der Werff & L. Daneu 4810; HRCB • Una Reserva Biologica de Una, near Rio Maruim ; 14 Nov. 2000; I. Fernades, S.C. Sant ʼ Ana & M. Caravallo 1498; NY • Barro Preto, ca 13.5 km on street from Barro Preto to the access to Serra da Pedra Lascada ; 14°46′22″ S, 39°32′16″ W; 960 m a.s.l.; 13 Aug. 2003; P. Fiaschi, A.M. Amorim, S. C. Sant ʼ Ana & J.L. Paixão 1574; NY GoogleMaps .

Description

Trunks 0.7–1.5 m tall, ca 8–10 cm diam., with old petiole bases, straight to decumbent; without adventitious buds. Petioles ca 35–50 cm long, inermous to sparsely muricate, brown to dark purpureous, matte; scurf absent. Petiole scales lanceolate, 14.0–20.0 × 4.0– 4.5 mm, their tips straight, concolorous yellowish to white, sometimes with dark central stipe, auburn to dark brown. Leaves to 230 cm long; patent and distally arching. Blades to ca 180 × 90–120 cm, bipinnate-pinnatifid, firm herbaceous to chartaceous; dark shiny green adaxially, often blackish when dried, pale olive green abaxially; apices abruptly reduced to a non-conform section. Pinnae to 35–65 cm long, number of pairs per leaf ca 8–10, stalked 1.0– 2.5 cm, patent to ascending, basal pinnae ca ⅔ the length of longest pinnae, patent to weakly reflexed; pinnae distally green alate; distal pinnules free, the pinnatifid terminal segments shortly decurrent into the costae. Leaf axes brown to carnose on both sides, the costules abaxially often blackish; with whitish to brown, antrorsely curved hairs to 0.8 mm long adaxially, abaxially glabrescent with scattered, appressed, tan to brown trichomidia; abaxially with auburn to orange-brown squamules with entire margins and white tips, bullate or flat, 0.4–1.0 mm long; costae inermous, 1.5–3.0 mm wide; insertions of costae into rachises not or only abaxially weakly swollen, without clearly developed pneumathodes, usually blackened in dried specimens. Pinnules to 7.0–11.5 × 1.5–2.0 cm, short stalked to 3 mm, alternate, 1.5–3.0 cm between the stalks; linear-oblong, bases truncate to weakly cordate, long attenuate tips, and with finely serrate margins; incised to ½ or more of their width, with acute sinuses to 2 mm wide, weakly dimorphic, sterile part of pinnae and pinnules wider with narrower, often occluded sinuses; the carnose to brown stalks inarticulate, with a black ring at their bases (abscission layer?), without pneumathodes; segments oblong to deltate, patent to ascending, with subentire to finely crenulate margins, in the latter case weakly revolute; tips straight to weakly falcate, rounded to obtuse; basal segments opposite to alternate, the lowest ones not remote from each other. Veins planar, carnose to dark brown abaxially and adaxially, ending shortly before the segment margins, becoming wider and reddish adaxially; glabrous adaxially, abaxially with appressed, tan trichomidia and thin, hyaline, twisted hairs to 1 mm long, with auburn to orange-brown bullate squamules with entire margins, sometimes larger, flattish squamules to 2 × 1 mm proximally on midveins and on costules; no hairs between veins; sterile simple, fertile veins forked, rarely simple. Sori 0.8(–1.0) mm diam., inframarginal to marginal, parallel to the margins, usually in the forks of veins, indusia absent; receptacles globose to ellipsoid, 0.3–0.4 mm diam., without subtending scales; paraphyses few, hyaline, tan to reddish brown, shorter than the sporangia (0.2 mm). Spores with smooth exospore, finely pitted (Gastony 1979).

Distribution and ecology

Northeastern Brazil at elevations of 550–960 m a.s.l., in the understory of Mata Atlântica.

Remarks

Cyathea praecincta has been often misidentified as C. pungens when petiole scales are missing (mostly concolorous white in C. praecincta vs strongly bicolorous with white margins in C. pungens ), but the whole appearance and coloration of its specimens differs strongly from true C. pungens . Dried specimens have the blades bicolorous, with blackish adaxial side and olive to grayish green abaxial side (vs ± the same color in C. pungens , varying from pale green to brown depending on preservation) and the axes are a homogenous reddish brown to atropurpureus (vs yellowish to pale brown in C. pungens ). Cyathea praecincta has many fertile veins forked while they are generally simple in C. pungens . According to our data, both species have clearly separated dstributions ( Figs 1–2 View Fig View Fig ).

From Alagoas, we have seen only images of specimens without petiole (W.W. Thomas 12419, MO, NY), which may be C. macrocarpa (C. Presl) Domin. The specimens have the lowest segments slightly smaller than the following in the pinnules, and the margins slightly dentate, which matches more C. macrocarpa than C. praecincta . Cyathea macrocarpa is scatteredly distributed from northeastern Brazil to the Guayana shield ( Lehnert 2011). Both species occur together, have submarginal sori and very pale petiole scales, and they are often not distinguishable from photos alone (https://www.inaturalist.org/observations/103467779). A closer look at the sori allows a clear separation as C. praecincta has no indusium, which is easily discernable due to the sparse paraphyses, whereas C. macrocarpa has a dense mass of long persisting paraphyses that hide a well developed hemitelioid indusium.