Saxofridericia brasiliensis P.E.Berry & Krahl, 2017

Berry, Paul E. & Krahl, Amauri Herbert, 2017, A new species of Saxofridericia subgenus Acrotheca (Rapateaceae) from Amazonas State, Brazil, Phytotaxa 326 (4), pp. 284-288 : 285-288

Saxofridericia brasiliensis P.E.Berry & Krahl , sp. nov.

Type:— BRAZIL. Amazonas: on white sandstone, km 140 of Manaus-Caracaraí Road, 27 September 1973, C. C. Berg, F. A. Bisby, W. C. Steward & J. F. Ramos P 18164 (holotype NY!, isotypes INPA!, MG!, US!). Figs. 1 , 2 .

Diagnosis: Saxofridericia brasiliensis is most similar to Saxofridericia aculeata Körnicke , but differs in the entire to finely spinulose margins of the leaf blades, petioles and upper leaf sheaths (vs. spinose petioles and spinulose leaf margins), narrower leaf blade (2.5–4.5 cm vs. 4–10 cm), and lack of finely reticulating tertiary leaf veins (vs. transversely reticulate tertiaries).

Terrestrial herbs (0.8–)1.0– 1.5 m tall, sheaths equitant, flattened, 9–20 cm long, 1.5–2.5 cm wide at the center, entire-margined or finely spinulose. Petioles (5–)25–70(–85) cm long, 3–5 mm wide, usually 1–2 times as long as the blade, with a prominent midvein, entire to finely spinulose. Leaf blades 25–65 cm long, (2.5–) 3–4.5 cm wide, firm, smooth except for the protruding midrib on ventral side, the midrib off-centered at the base, the base abrupt, inequilateral, one side 0.2–1.5 cm shorter than the other, the basal lobes usually scarious-spinulose along the margins, the rest of the margins entire or spinulose near the base, tertiary leaf veins inconspicuous. Peduncles erect, 13–40 cm tall, generally 1–3 per plant, 5–10 mm wide and slightly flattened to triquetrous below the head; inflorescence subglobose, 2.2–3(–3.5) cm diam., tightly covered by brownish-tan, attenuate-acuminate bracts 3–5.5 cm long, extending 1–2(–3) cm beyond the head and remaining connate to the tip but rupturing longitudinally, the lower portion perforated by the spikelets at anthesis; spikelets 40–80, bracteoles (18–)20–22, 7–8 mm long, ca. 1 mm wide, broadly oblanceolate, shortly subulate-lanceolate, subequal, becoming sharply convolute toward the acuminate tip; sepals 3, 6–10 mm long, lanceolate, free to base, becoming involute with an apiculate tip; petals 3, basally united into a tube, then with free, imbricate, yellow, obovate blades 6–8 × 3.5–4.5 mm, patent at anthesis, with an apiculate tip. Stamens 6, anthers 4- lobed, 4.5–5 mm long, 0.7 mm wide basally, whitish, rugulose, the anterior lobes opening into 2 subterminal pores, posterior lobes projected as an acute, lanceolate appendage 1.0– 1.2 mm long. Style subulate-trigonous, ca. 6 mm long, pale yellow-white, the stigma terminal and minute; ovary trilocular, 2–4 ovules per locule. Capsule oblong-obovoid, basally membranaceous, distally indurated, loculicidal; a single seed developing, reniform, transversely rugose, 3–4 mm long.

Ecology and distribution: — Saxofridericia brasiliensis grows in colonies in seasonally swampy understorey and streamsides of white-sand campina scrub forests at elevations of 120– 180 m. It is currently known from Amazonas State, Brazil, in two main areas north of Manaus, the first along a side road off of Km 21 of BR-174 (the Manaus-Caracaraí highway) in the Ramal Vale do Novo Amanhecer, and the other between Km 130 and 202 of BR- 174 in the general area of Presidente Figueiredo.

Pollination: —During field observations at Vale do Novo Amanhecer, we observed buzz pollination (vibration of the anthers to collect pollen) primarily by female Euglossa bees and secondarily by Augochloropsis bees.

Additional specimens examined (paratypes): — BRAZIL. Amazonas : Manaus-Caracaraí road, Km 140, 13 November 1973, Berg, Lleras, Holley & Monteiro P19498 ( INPA, MG, MO, NY, P, R, US) ; Manaus-Caracaraí road, Km 130, [Igarapé Lages], 1 December 1974, Gentry 12948 ( INPA, MG, MO, NY), ibid. loc., 9 May 1974, Prance, Nelson, Monteiro & Lima 21040 ( INPA, NY), 31 August 1974, Prance, Pennington & Conceição 21695 ( INPA, NY, US), 10 December 1976, Silva, Coelho & Ribamar 1998 ( INPA), 10 December 1973, Steward & Ramos P20092 ( INPA, NY) ; Km 202, Manaus-Itacoatiara, near Rio Urubu, 19 December 1966, Prance, Pena, Ramos & Monteiro 3744 ( INPA, NY, US) ; Comunidade Vale do Novo Amanhecer , Ramal Vale do Novo Amanhecer , próximo ao lote 6—“Toca da onça”, entrada pelo Km 21— Ramal do Pau Rosa , 14 July 2011, Krahl , Zidko , Correa, Melo, Araújo & Webber 250 ( INPA), ibid. loc., 14 July 2011, Krahl, Zidko, Correa, Melo, Araújo & Webber 251 ( INPA), ibid. loc., 14 July 2012, Krahl 409 ( INPA) .

Conservation assessment: —Although this species appears to be quite restricted in its distribution, it is locally common, and there are other areas with similar habitats that have not been sampled. We designate its conservation status as Data Deficient ( IUCN 2012) until further assessments can be carried out.

Notes: —Of the other four described species in Saxofridericia subgenus Acrotheca , three are restricted to the upper Rio Negro in southwestern Venezuela, southeastern Colombia, and northernmost Amazonian Brazil; these species ( S. colombiana , S. inermis , and S. petiolata ) tend to have smaller heads that are less spherical and more laterally compressed, with the base of the inflorescence sheath persistent on the head. The remaining species, S. aculeata , is the most similar to S. brasiliensis , but is usually more robust, with wider leaves (4–10 cm vs. 2–4.5 cm) and with much more spinose margins of the dorsal spine of the leaf sheaths, petioles, and base of the leaf margins ( Fig. 3 ). A key to the species of Saxofridericia subgenus Acrotheca is provided below.

Saxofridericia aculeata is the most widespread species in the genus, occurring in Suriname, French Guiana, Guyana, Venezuela, Colombia, and Brazil. In Brazil, it is known from Amapá, Pará, and Amazonas States, with the nearest localities to S. brasiliensis close to Vale do Novo Amanhecer in the Reserva Ducke and then north of Presidente Figueiredo at the Rio Urubu.

Among the specimens of Saxofridericia brasiliensis cited, two (Prance et al. 21695 and Silva et al. 1998) have very short petioles (5–10 cm long) compared to the other specimens. We observed the same phenomenon in the field at Lajes near Presidente Figueiredo, and this may be due to younger plants in which the petioles have not fully extended.

Figures

FIGURE 1. Saxofridericia brasiliensis. A. Habitat—campina forest along stream over sandstone outcrop in Reserva Ecológica Lajes near Presidente Figueiredo, Amazonas State, Brazil. B. Two adjacent heads in anthesis. C. Habit showing long-petiolate, lanceolate leaves. D. Two heads post-anthesis showing persistent, perfoliate bracts. Note also the long petioles and unequal leaf bases. Photo credits: A, D: P. Berry; B: A. Krahl; C: B. van Ee.

FIGURE 2. Saxofridericia brasiliensis. A. Habit. B-C. Inflorescence. D. Flower in side view. E. Flower in front view (A.H. Krahl et al. 250). Drawn by M.M. Corrêa.

FIGURE 3. Comparison of the leaf bases and venation of Saxofridericia aculeata (A) and S. brasiliensis (B).A: J.F. Pruski 3216 (INPA), B: C.C. Berg et al. P19498 (INPA).