Glandonia prancei W.R. Anderson, Mem.

Guesdon, Isabel Reis, Amorim, André Márcio & Meira, Renata Maria Strozi Alves, 2018, The hydrochorous Amazonian genus Glandonia (Malpighiaceae): new records, morphoanatomy updates and taxonomic contributions, Phytotaxa 345 (1), pp. 13-25 : 21

2. Glandonia prancei W.R. Anderson, Mem. New York Bot. Gard. 32: 147. 1981.

Type:— BRAZIL. Amazonas : Humaitá , Rio Madeira, Rio Ipixuna, 26 November 1966, Prance, Pena & Ramos 3363 (holotype INPA!, isotypes GH, K, MICH, MO, NY!, S, VEN). ( Figures 1D ; 2D ; 3B, C, E, J ; 4B, G, J, L ; 5 D-F)

Description —Trees, ca. 18 m tall; branches glabrous. Leaf entire, lamina 9–21 × 4–6 cm long, elliptical or rarely slightly obovate, base cuneate, apex acuminate, margin flat or slightly revolute, papyraceous, adaxial and abaxial surfaces sparsely sericeous to glabrescent, abaxial surface with (0)2 basilaminar white glands, laterally positioned at the midrib, ca. 0.5 mm diameter, inconspicuous glands randomly distributed throughout the blade, 0.2–0.3 mm diameter; petiole 7–25 mm, glabrous; stipules 12–24 mm long, glabrous. Inflorescence a raceme of cincinni, 5–11 cm long, appressed-tomentose, cincinni with 3–5 flowers; bracts and bracteoles ovate, apex slightly acute, concave, abaxially sericeous; bracts 2–4 mm long, eglandular; bracteoles 1–3 mm long, bracteole gland white, with discoid-flat secretory surface. Floriferous peduncle 2–4.8 mm long. Pedicel 6–8.3 mm long, appressed-tomentose, joint distinct. Sepals 1.5–2 mm beyond sepal glands, apex rounded, abaxially sericeous, sepal glands 2–3 mm long, white. Petals glabrous, outermost petal helmet-shaped, white, limb ca. 6 × 4.5 mm, denticulate, claw ca. 5 mm long, reflexed; lateral petals white, limb ca. 6 × 6 mm, sagittate, eglandular, margin entire, claw ca. 3.5 mm long, reflexed; posterior petal yellow, limb 3.6–4 × ca. 4 mm, reflexed, base sagittate, with ca. 12 marginal glands on the proximal portion, ca. 0.3 × 0.3 mm, claw 3.5–4 mm long, erect. Filaments ca. 1 mm long, densely hirsute just above of the insertion of the anther; anthers 3–4.5 mm long. Ovary ca. 1.3 mm long, pyramidal, glabrous; styles three, 4.5–5.5 mm long, subequal, glabrous, ca. 1 mm bent at apex toward the center of flower. Fruits 1.6–3.3 × 0.6–1.9 cm, cylindrical, becoming truncate-conoid, with 16–18 longitudinal grooves, forming rounded projections at the base, styles persistent.

Specimens examined— BRAZIL. AMAZONAS: Beruri, RDS Piagaçú-Purus, 22 January 2011 (bud), B. G. Luize 282, 304 ( INPA) ; ibid., 28 February 2015 (bud, fl), Silva -Guesdon et al. 298, 299 ( VIC) ; Humaitá, Banks of Rio Ipixuna , 26 November 1966 (fl) ; Lábrea, Lago Preto, norte de Lábrea, 29 October 1968 (bud), Prance 8058 ( NY!, P) ; Careiro, Igapó-Açú, BR 319 , 15 March 1974 (fr), G. T. Prance et al. 20557 ( INPA, MG, NY!) .

Notes on morpho-anatomy— This species resembles Glandonia macrocarpa because of the inconspicuous laminar leaf glands ( Fig. 4J ) and slightly sinuous outline of the anticlinal epidermal cell walls of the leaf ( Fig. 4B ); however, it differs by its elliptical or rarely slightly obovate leaf. The posterior petal is yellow ( Fig. 5D ), as in G. macrocarpa , while the basilaminar leaf glands ( Fig. 3E ) and bracteole glands ( Fig. 3J ) in G. prancei are exclusively white. The pattern of the vascular system differs from G. macrocarpa because it is a curved arc with invaginated ends ( Fig. 4G ). Other important features that distinguish G. prancei from G. macrocarpa are the distinct pedicel joint ( Fig. 3I, J ), the truncate surface of the bracteole glands ( Fig. 4L ) and the smallers petal glands ( Fig. 5E, F ).

Etymology —The specific epithet honors the botanist Ghillean Tolmie Prance.

Distribution, habitat and conservation —This is the rarest species of Glandonia , which is only known from four localities in the Rio Purus and Madeira ( Fig. 1A ). A specimen of Glandonia prancei was recently discovered, but misidentified as G. macrocarpa . It was collected in 2011 (Luize 282, 304) at the lower Rio Purus, and is the first record of the species since 1974 (Prance et al. 20557). This new record is strong evidence of poor sampling in Amazonia, and reinforces the need to conduct more fieldwork to clarify the distribution range of the species.

Based on its EOO = 49,090.842 km 2, Glandonia prancei is categorized as Least Concern (LC). This species has been poorly sampled and although the small AOO value (16.000 km 2), population size and restricted distribution (D1 + D2 sub-criteria) suggest an endangered status, there are many similar habitats along the Purus and Madeira rivers this species could occupy. However, fieldwork at the type locality has failed to find any new populations. This species has only been recently collected at a single locality, fortunately, this is within a conservation area.

Phenology — Glandonia prancei has been collected in flower from October to February and in fruit at March.

Figures

FIGURE 1. A. Map showing the distribution of Glandonia macrocarpa (black triangles), G. prancei (black circles) and G. williamsii (black squares). B. Glandonia macrocarpa specimen (arrow) in terra firme forest. C. Glandonia williamsii specimen (arrow) in igapó. D. Hydrochorous fruit of G. prancei.

FIGURE 2. General view of Glandonia species: A and B Glandonia macrocarpa: A. Flowering branch, B. lateral and frontal view of fruit. C. Fruiting branch of G. williamsii. D. Fruiting branch of G. prancei. Drawing A from Guesdon 16 (INPA), B from Ducke 793 (INPA), C from Fróes 28782 (MG) and D from Prance et al. 20557 (INPA).

FIGURE 3. Vegetative and reproductive characters of Glandonia species: A. keel-shaped leaves of G. williamsii, B. and C. general view of leaves and inflorescence of G. prancei. Basilaminar leaf glands: D. Glandonia macrocarpa, E. Glandonia prancei and F. Glandonia williamsii. Laminar leaf glands: G. Glandonia williamsii and H. Glandonia macrocarpa. Floral glands: I. bracteole gland (BG) of G. macrocarpa, J. bracteole and sepal glands of G. prancei (BG and SG, respectively), black arrow: pedicel joint. K. Posterior petal in bud of G. macrocarpa, note the petal glands (arrow) L. Helmet-shaped petal (HP) and reflexed limb of posterior petal (PP) in G. macrocarpa.

FIGURE 4. Anatomical characters of Glandonia species. A. Adaxial surface of G. macrocarpa showing indument scars (black arrow). B. Abaxial surface of G. prancei showing a stoma (black arrow) and sinuous outline of the anticlinal epidermal wall. Abaxial surface of G. williamsii C. papillae covering a stoma (black arrow), D. papillose surface (SEM image), a stoma (white arrow). E. Transversal section of leaf of G. williamsii, papillae (white arrow), F. Sclereids in midrib of G. macrocarpa (black arrow). Diagrammatic schemas of petiolar vascular systems G. a curved arc with invaginated ends in G. prancei and H. a concentric arc delimiting a central pith in G. macrocarpa, dot-filled areas: phloem, striped areas: xylem. Leaf blade cleared I. in G. williamsii and J. in G. prancei, note the laminar gland (arrow). Transversal view of bracteole gland K. convex surface in G. macrocarpa, L. truncate surface in G. prancei. M–O. Sclereids on posterior petal of G. williamsii, N. Macrosclereids, O. Brachysclereids.

FIGURE 5. Morphoanatomical floral characters of Glandonia species. A–C: Glandonia macrocarpa: A. General view of the flowers, B. Posterior petal margin (SEM image) and C. Posterior petal cleared. D–F: Glandonia prancei: D. General view of the flowers, E. Posterior petal margin (SEM image) and F. Posterior petal cleared; G–I: Glandonia williamsii: G. General view of the flowers H. Posterior petal margin (SEM image) and I. Posterior petal cleared. PP: Posterior petal. SG: Sepal glands. BG: Bracteole gland.