Arrojadoa flava Gonzaga & Engels 2023, sp. nov.
Creators: name: Gonzaga, Diego Rafael
name: Liebsch, Dieter
name: Engels, Mathias Erich
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Caryophyllales
Cactaceae
Arrojadoa
Arrojadoa flava

description: Arrojadoa flava Gonzaga & Engels sp. nov. (Figures 1–3).
Type:— BRAZIL. Bahia: Ibitiara, Cadeia do Espinhaço, Chapada Diamantina, 07 September 2022, fl. and fr., Engels & Liebsch. 9.900 (holotype RB840645!, isotype UPCB!).
Diagnosis:— Arrojadoa flava resembles A. bahiensis (Braun & Esteves Pereira 1993: 16) Taylor & Eggli (1993: 98) from which differs by the stems mostly unbranched vs. branched only at the base; cephalium apical present vs. undifferentiated distal flowering region, yellow flowers (external part) vs. pink flowers, size of flowers (1.9–2.5 × 0.5– 0.8 vs. 2.9–3.9 × 0.8–1.1 cm), style length (10–12 vs. 25–28 mm long) and white mature fruit vs. pink mature fruit.
Description:—Terricolous to rupicolous, simple root system with fibrous roots, subglobose to globose plants, 14 cm to 1 meter hight, unbranched at base, lonely, branched only at the apex when cuts, erect or lightly inclined, green cladodes, 8.5–9.5 cm diameter., ribs 14–17, in-depth 8.5–11.0 mm; areoles 2.5–3.9 mm diameter, spaced 1–4 mm apart; flowering regions at apex differentiated in cephalium c. 25 mm., broken spines, slightly flexible, grayish to the base and yellowish the medium/apex spines, central 1–2, 15–25 mm long., radials 3–10 mm long., up to 17 per areole. Yellow floral buds, naked. Flowers externally yellow, internally white, 1.9–2.5 × 0.5–0.8 cm, flower-tube with yellow scales, ca. 1 × 1, triangular, acuminate apex, ciliated, pericarpel naked, triangular, ca. 2 × 4 mm, nectarchamber present, ca. 4 × 4 mm, perianth-segments 27–34, the external 2–3 × 1.5–2.0 mm, fleshy, triangular to elliptical, papillose, ciliated, acuminate apex, the internal 3–4 × 1.8–2.5 mm., delicated, lanceolate, narrowed base and widened apex, stamens 191–206, in a continuous series, filaments 3–4 mm long, style 10–12 × 0.7–1.0 mm, stigma-lobes 5, lobes 1–2 mm long. Fruit 13–20 × 10–14 mm, ovoid to piriform, yellow immature, white mature, perianth-segments persistent, funicular pulp white and translucent, reminiscent base of the deepened flower. Seeds cochleariform, black, 1.23–1.36 × 0.79–0.96 mm, 0.55–0.64 thickness, bright.
Etymology: —The specific epithet refers to the yellow color of the flowers.
Phenology and ecology: —Flowering time in September. The flowers present diurnal anthesis and observed open about 7 a.m., and around 4 p. m. are already fully open. A punctually observed record of the hummingbird of the species Chlorostilbon lucidus (Shaw 1812: 312) as a visitor in the flowers of Arrojadoa flava.
Distribution and habitat: — Arrojadoa flava is represented by a single population with a large number of individuals, distributed along approximately 5 km of a white rock mountain range (sandstone with quartz clasts), at elevation of 1200–1250 m a.s.l. in Ibitiara municipality, Bahia state, Chapada Diamantina in in the northern portion of Espinhaço Range. The vegetation that occurs in this place is “Campo Rupestre”, Caatinga Domain. This population is sympatric with other cactus species such as Melocactus concinnus Buining & Brederoo (1972: 23), Micranthocereus purpureus (Ģrke 1908: 86) Ritter (1968: 157), Pilosocereus pachycladus subsp. pernambucoensis (Ritter 1979: 65) Zappi (1994: 109), Stephanocereus luetzelburgii (Vaupel 1923: 57) N.P.Taylor & Eggli (in Hunt & Taylor 1991: 91), Tacinga inamoena (Schumann 1890: 306) N.P.Taylor & Stuppy (in Taylor et al. 2002: 119), and not being found Arrojadoa bahiensis in this area, with no overlap of occurrence. Additionally, Arrojadoa rhodantha (Ģrke 1908: 70) Britton & Rose (1920: 170) was found in the Ibitiara municipality, however not occurring in sympatry with the new species.
Conservation status:— According to the IUCN criteria (2017), Arrojadoa flava is here assessed as Data Deficient (DD). Known only from two collections from a single population, it needs more sampling focus, which may result in the finding of more populations in different localities, increasing knowledge of the actual conservation status of this new species. The area where individuals were found suffers from habitat loss, mainly due to the creation of roads.
Additional material examined:— BRAZIL. Bahia, Ibitiara, Cadeia do Espinhaço, Chapada Diamantina 06 September 2022, fl. and fr., Engels & Liebsch 10.000 (paratypes: RB840.646! [3 sheets], UPCB! [2 sheets]).
description: Published as part of Gonzaga, Diego Rafael, Liebsch, Dieter & Engels, Mathias Erich, 2023, Arrojadoa flava (Cactaceae, Cactoideae), a new yellow flowered species from the Brazilian flora, pp. 73-79 in Phytotaxa 597 (1) on pages 74-78, DOI: 10.11646/phytotaxa.597.1.8, http://zenodo.org/record/7918830