Grias densiflora Cornejo, 2025

Cornejo, Xavier & Prance, Ghillean T., 2025, Three new species of Grias (Lecythidaceae) from Colombia and Ecuador, Phytotaxa 684 (2), pp. 289-297 : 294-296

3. Grias densiflora Cornejo , sp. nov. ( Fig. 3 )

New species of Grias , similar to G. haugthii R. Knuth (1939: 31) , but G. densiflora differs by the stiffly coriaceous leaf blades (vs. coriaceous), irregular raceme rachises with dense protruding pedicel scars throughout (vs. smooth, with loose pedicel scars), shorter pedicels (10–13 mm vs. 15–25 m long), calyx glandular dark punctate, shorter sepals (5–6 vs. 7–9 mm), and ovary longitudinally costate at apex (vs. ovary smooth at apex).

Type: — ECUADOR. Antioquia : Río La Miel, hacienda “La Rica” un poco más abajo de la desembocadura del río Samaná, ca. 5°40′N 74°46′W, 8 Aug 1965 (fl), A. Fernández-Pérez & R. Jaramillo M. 7100 (holotype, 2 parts: NY-00809973 ! (infl.), NY-00809972 ! (leaf blade); isotypes COL!, NY-00809971 ! (leaf blade).

Pachycaulous, understory trees, ca. 10 m tall, the trunk cylindrical, not buttressed. Bark rough, grayish and brown. Stems unknown. Leaves clustered at apices of trunk or stout branches of stems; petioles lacking to 50 × 15–20 mm, semicircular in cross section, glabrous; blades oblanceolate or spathulate, ca. 160–170 × 30–42 cm, stiffly coriaceous, glabrous, punctate abaxially, the base tapering, revolute, the margins dentate, the apices acuminate; venation brochidodromous, the secondary veins ca. 40–45 pairs, those in middle of lamina 2.5–5 cm apart in mature leaves, the tertiary veins weakly percurrent, the higher order venation difficult to see ad- and abaxially. Inflorescences cauline, racemose, flowering in succession up to 40 flowers per rachis but up to 5 flowers at time, the rachises irregular with very densely arranged protruding pedicel scars throughout, up to 60 mm × 2–5 mm; pedicels 10–13 mm long, subtended by a single, triangular bract, 1–2.5 × 1–1.5 mm. Flower buds globose; mature flowers ca. 3 cm in diam.; hypanthium glabrous; calyx glandular dark punctate, enclosing bud, splitting into 2–4 irregular lobes at anthesis, the lobes 5–6 × 3–5 mm, hemiorbicular to deltoid; petals ovoid to elliptic, ca. 20 × 8 mm, yellow, spreading at anthesis, with inconspicuous dark brown marginal glands (observable in fresh material); androecium obloid, the staminal tube ca. 1.5 mm high, arching from base to apex, divided into 2 chambers, with 80–100 stamens, the filaments bent inward and tapering at apex, the outermost ca. 7 mm long, yellow, the connectives absent, the anthers suborbicular, 0.6–0.8 mm long, with lateral dehiscence; ovary 4-locular, with 1–2 ovules per locule, glabrous, the apex umbonate, longitudinally costate, a nectary disk absent, the style less than 0.5 mm long. Fruiting pedicel, fruit, and endocarp not seen.

Discussion: —Among congenerics, Grias densiflora is unique in having stiffly coriaceous leaf blades, cauline racemes projecting rachises crowded with very densely arranged protruding pedicel scars throughout, and top of ovary thinly costate. The acropetous racemes densely produce up to 40 flowers in succession (judging by the scars) on a rachis 60 mm long, suggesting a particular floral behavior that deserves further field research. In the revision of Grias (Mori in Prance and Mori 1979), the type collection of G. densiflora (Fernández-Pérez & Jaramillo 7100) was cited as Grias haughtii , a name originally used by the same collector for identification, as it is typewritten on the label. However, the characters discussed in the diagnosis do not fit the type collection of the latter species. Furthermore, based on fieldwork observing Grias for 30 years on both sides of Andes, there is no other species with racemose inflorescences with such a dense and a high number of flowers on a relatively short rachis. Thus, it deserves taxonomic recognition.

Etymology: —The epithet densiflora refers to the racemose inflorescences with characteristic rachises with dense pedicel scars suggesting a crowded flower arrangement.

Common names: —Unknown.

Habitat and distribution: —An understory to medium-sized tree known only from the type locality, in the lowlands of the department of Antioquia, Colombia.

Phenology: — Flowering specimens have been collected in August.

Conservation status: — Grias densiflora is known only from the type locality. As the area of occupancy of the species is less than 100 km 2, and because no other specimen of this species has been gathered or found in herbaria since the type was collected in 1965, it is suggested that this new species be assigned the Critically Endangered (CR) status following the IUCN criterion B1 ( IUCN 2022).

Figures

FIGURE 3. Grias densiflora. A. Cauline racemose inflorescences attached to and detached from pieces of bark and rough bark, note the irregular rachises with very densely arranged protruding pedicel scars throughout; B. Close up of filaments and anthers; C. Close up of pistil, note the umbonate costate top of ovary and inconspicuous style crowned by a 4-lobed stigma; D. Hypanthium and calyx, lateral view; E. A dry herbarium folded leaf blade, adaxial and abaxial view, note the dentate margin, the very narrowly and elongate decurrent leaf base, abaxially channeled petiole, and very prominent midvein. (A–E, based on Fernández-Pérez & Jaramillo 7100, the type). Photos by Xavier Cornejo.