Amorimia tumida R. F. Almeida & A. C. Marques 2017, sp. nov.
Creators: name: Almeida, Rafael Felipe De
name: Mello, Ana Caroline Marques Pereira
name: Oliveira, Denise Maria Trombert
name: Amorim, André Marcio Araújo
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Malpighiales
Malpighiaceae
Amorimia
Amorimia tumida

description: Amorimia tumida R.F.Almeida & A.C.Marques, sp. nov. (Figs. 1–5)   
 Type:— BRAZIL. Rio de Janeiro: Mun. Cardoso Moreira, Serra da Bandeira, 17 December 2013, fr., M. N. Coelho & I. G. Costa 2794 (Holotype: RB!; isotypes: CEPEC!, HUEFS!).   
 Differs from Amorimia andersonii by its elliptic leaf blades, eglandular base, fewer secondary veins, secondary veins joining the primary vein in an acute angle, more obtuse in the apex; fewer flowers in the inflorescence; pedicel tumid in fruits; filaments entirely sericeous; styles entirely sericeous; samaras sericeous and metallic coloured.   
 Woody vine; stem sparsely sericeous to glabrous at age; stipules 0.5–0.6 mm long, triangular, epipetiolar, persistent to deciduous. Leaves opposite, reduced to bracts in the inflorescences; petioles 4.3–6.6 mm long, sparsely sericeous to glabrous, eglandular at apex; blades 4.0–9.5 × 2.1–5.1 cm, plane, elliptic, base obtuse, margin slightly revolute in sicco, apex acuminate, adaxially glabrous, abaxially sparsely sericeous to glabrescent at age, eglandular; midvein adaxially prominent, abaxially prominent, 8–9 pairs of secondary veins, arching 48–55°, opposite to subopposite, both sides impressed, reticulum impressed and conspicuous on both sides. Thyrses (pseudoracemes) axillary; main axis 8.45–9.75 cm long, cylindrical, striated, sericeous; cincinni 1-flowered, 6–8-cincinni, decussate; bracts 1.3–3.3 × 1.0– 1.6 mm, lanceolate, petiolate, conduplicate, deflexed, 1 pair of marginal glands near base, both sides sericeous; peduncle 11–20 × 0.7–1.0 mm, laterally flattened, sericeous; bracteoles 1.1–1.8 × 0.5–0.6 mm, oblong, sessile, conduplicate, inserted 2.5–4.0 mm below the apex of peduncles, subopposite, deflexed, eglandular, both sides sericeous. Flowers unknown; floral buds (fragments) 5.5–8.0 × 5.0–6.0 mm; pedicels (in fruits) 6.0–8.0 × 1.0– 1.5 mm, sericeous to glabrescent, tumid. Sepals (in fruit) 3.5–4.0 × 2.5–3.0 mm, narrowly oblong, apex obtuse to rounded, revolute at anthesis, both sides sericeous; glands 3.0–3.1 × 1.3–1.5 mm, greenish turning brown at age. Petals unknown. Stamens (persistent in young fruits) 10; filaments 1.8–2.0 × 0.5–0.7 mm, connate 1.0– 1.5 mm long at base, entirely sericeous on both sides; anthers unknown. Ovary unknown (probably sericeous); styles 3, cylindrical at base, cylindrical at apex, parallel at base and middle, apex apiculate, entirely sericeous; anterior style 2.0– 2.1 mm long; posterior styles 2.5–2.8 mm long; stigma lateral, crateriform. Samaras metallic green in vivo and metallic ocher in sicco; dorsal wing 10–15 × 5.0–6.0 mm, depressed ovate, margin entire, sericeous on both sides; lateral wings 1.6–2.3 × 1.8–3.0 cm, flabelliform, margin entire to sinuate, upper angle 15° and lower angle 55° from the nut, sericeous on both sides; nut narrowly ovoid, sericeous; areole 8.6–10.0 × 2.6–3.5 mm, narrowly ovoid. Seeds 6.1–9.0 × 3.5–6.5 mm, testa rugose with lateral crests; embryo ovoid, cotyledons folded.   
 Distribution, habitat and phenology: — Amorimia tumida is known only from semi-deciduous forests in northern Rio de Janeiro state (Fig. 5), fruiting in December.   
 Conservation status: —Despite recent efforts, we were unable to find A. tumida in its type locality on Northern state of Rio de Janeiro again. The collector of the type specimen did not record geographic coordinates for the specimen, and little was written in the specimen’s label regarding habitat and locality. Unfortunately, this species remains known by a single collection from semi-deciduous forests associated to rocky outcrops within the Atlantic Forest of Serra da Bandeira, northern Rio de Janeiro state. Thus, based on our findings this species should be regarded as Data Deficient (DD).   
 Etymology: —The epithet makes reference to the species thickened fruiting pedicels, a unique feature in the genus.   
 Leaf anatomy: — Amorimia tumida and A. andersonii are quite similar in their leaf anatomy (compare Fig. 3a–b with Fig. 3c–d). In the distal third, the petioles of both species show thin-walled cells in the epidermis of both sides (Fig. 3e, g). In A. tumida, a sub-epidermal layer similar to the epidermis is observed in the entire petiole, but cells here are larger than in the epidermis (Fig. 3e); the sub-epidermal layer is undifferentiated in A. andersonii (Fig. 3g). A slightly thickened collenchyma occurs adjacent to the epidermis and throughout the petiole (Fig. 3a, e and Fig. 3c, g). This is more evident in A. andersonii. In transversal section, the main vascular unit shows secondary growth and forms an open arch with non-convoluted extremities arranged collaterally (Fig. 3a, c, f, h). Two accessory vascular bundles are arranged adaxially at each side of the main vascular unit (Fig. 3a, c).   
 The leaf blade of both species is hypostomatic (Fig. 3i, l) with paracytic stomata (Fig. 3j, m) occurring at the same level of the ordinary epidermal cells (Fig. 3i, l). The cuticle is thin and cuticular flanges (Fig. 3k, n) can be seen throughout the leaf blade extension. The epidermis is single-layered and shows thin cell walls. In transverse section, the epidermal cells are larger on the adaxial face than on the abaxial one (Fig. 3i, l). Furthermore, the cells are larger on the semi-blade and smaller on the primary vein on both sides (Fig. 3b, d). At the blade margin in A. andersonii, it is also possible to notice a subepidermal layer similar to the epidermis (Fig. 3o, p). The leaf blade possesses collenchyma adaxially and abaxially in the midrib (Fig. 3b, d) and has a dorsiventral mesophyll (Fig. 3i, l, o, p), with a single-layered palisade parenchyma that extends all the way to the margin, in A. tumida (Fig. 3o); and ending before the margin in A. andersonii (Fig. 3p). Idioblasts containing druses occur in the palisade parenchyma (Fig. 3i, l) of both species. The margin is revolute in A. andersonii, showing a fiber block near the epidermis, separated by few layers of subepidermal parenchyma (compare Fig. 3o and Fig. 3p). The spongy parenchyma is composed of braciform cells and idioblasts containing druses (Fig. 3q, s). The midvein shows a secondary growth and with the same collateral disposition observed in the petiole (Fig. 3b–d). Fibers contour the primary vein with more layers of fiber occurring abaxially (Fig. 3b, d). Glands are present on the abaxial face of leaf blades for both species. The epidermis of these glands is composed by palisade cells and the subglandular parenchyma is different of the adjacent tissues, showing smaller, denser and juxtaposed cells (Fig. 3r, t).   
 Leaf architecture: —In A. tumida the leaf blade shows a camptodromous-brochidodromous venation pattern, with a straight and non-ramified primary vein (Fig. 4a), as we can also see in A. andersonii (Fig. 4b). Secondary veins are of moderate caliber and non-ramified (Fig. 4a, b). In the median region of the leaf blade, the angle of divergence between the secondary veins and the primary vein is acute in A. tumida (Fig. 4a), and straight in A. andersonii (Fig. 4b). This angle is more obtuse in distal secondary veins than in proximal ones in A. tumida (Fig. 4a), while A. andersonii divergence angles are uniform (Fig. 4b). The course of the secondary veins is uniformly curved, and join the superadjacent secondary vein in a right angle in A. tumida (Fig. 4a), and abruptly curves joining the superadjacent secondary veins in acute angle in A. andersonii (Fig. 4b). The last marginal veins form arches on both species (Fig. 4c, d). Areoles are imperfect in shape, randomly arranged, and predominantly quadrangular in both species (Fig. 4c, g). Veinlets vary from simple and linear to branched (Fig. 4d, h) in both species.
description: Published as part of Almeida, Rafael Felipe De, Mello, Ana Caroline Marques Pereira, Oliveira, Denise Maria Trombert & Amorim, André Marcio Araújo, 2017, Leaf anatomy and macro-morphology uncover a new species of Amorimia (Malpighiaceae) from Southeastern Brazil, pp. 179-190 in Phytotaxa 305 (3) on pages 180-185, DOI: 10.11646/phytotaxa.305.3.5, http://zenodo.org/record/13694905