Ipomoea buriliae Belo

Ipomoea buriliae Belo , sp. nov.

Figs. 2 View Fig , 3 View Fig

Ipomoea buriliae is similar to I. parasitica in having spiny projections along the stem, petiole, and peduncle, as well as cordate leaves, and prominent veins on the abaxial surface.However, I. buriliae can be distinguished by its leaves with pubescent indumentum with caudate apex ( vs. sericeous with apex acute), the outer sepals orbicular with apex retuse, and the inner sepals reniform with the apex obcordate, glabrous ( vs. elliptic with apex obtuse and mucronate – the outer sepals, and apex rounded and minutely mucronulate – the inner sepals, puberulent to glabrescent), white campanulate corolla ( vs. blue funnelform), filaments with tector trichomes at the base and along the structure ( vs. tector trichomes only at the base) (see Table 2 View Table 2 ).

Type: BRAZIL, Paraíba, Areia, campus da Universidade Federal da Paraíba, 6°58’10”S, 35°42’50”W, 550 m, 20.07.2024, D. Belo & E. Barbier 740 ( holo PEUFR!; GoogleMaps iso CSTR!, EAN!, UFP!). GoogleMaps

Climbing plants; branches glabrous, striated with spiny projections; internodes 5.5–12.3 cm long. Leaves ovate, 8.5–15 × 6.1–13 cm, base cordate, margins entire, apex caudate, adaxial surface pubescent with tector and sessile peltate glandular trichomes, abaxial surface pubescent to glabrescent with tector and sessile peltate glandular trichomes, peninervea venation, simple brochidodromous type, with eight to ten pairs of secondary veins; petioles 7.2–16 cm long, glabrous to glabrescent with tector and sessile peltate glandular trichomes, striate. Inflorescence cymose, 3–8-flowered; peduncles 9.4–31 cm long, glabrescent, glabrous; bracteoles linear, 0.3–1 cm long, base rounded, apex acute, glabrous; pedicels 1–2 cm long, glabrous, striate. Sepals 5, unequal, the 2 outer ones orbicular, 6.4–6.5 × 5.8–6.2 mm, base oblique, apex retuse, glabrous, the intermediate one reniform, c. 11 × c. 10 mm, the base oblique, the 2 inner ones reniform, 11.2–12.5 × 11.2–12.6 mm, base cordate, apex obcordate. Corolla campanulate, 5.8–6.2 cm long, white, glabrous, yellow abaxial mesopetal region. Stamens 5; filaments 9.5–17.35 mm long, tector trichomes at the base and along the structure; anthers 5.8–6.9 mm long, oblong, glabrous, pollen grains monads, apolar, very large size, spheroidal, pantoporate. Ovary conical, 1.4–1.5 × 2–2.2 mm, 4-locular; style entire, 30–34.5 mm long, stigmatic lobes 2, 1.4–1.8 mm long, 2-capitate with the surface verrucose. Capsules globose, 1–2 cm long. Seeds 0.6–1 cm long, pubescent.

Flowering & fruiting: Flowering from June to August and fruiting from July to September.

Habitat: The new species occurs in a humid forest enclave in Paraíba state, north of the São Francisco River, Brazil, at an elevation of about 550 m.

Distribution: The known distribution of I. buriliae is restricted to the type locality.

Etymology: The specific epithet is named in honor of Dr. Maria Teresa Buril, acknowledging her outstanding contributions to the study of the systematics and taxonomy of Convolvulaceae , as well as to the field of botany. Beyond being a notable researcher, Dr. Buril is an exceptional mentor, committed to fostering the development of new Brazilian scientists.

Additional specimens examined ( Paratypes): BRAZIL, Paraíba, Areia, campus da Universidade Federal da Paraíba, 6°58’02”S, 35°42’56”W, 563 m, 21.07.2024, D. Belo & E. Barbier 741 ( PEUFR!); GoogleMaps Ibid.,, 6°58’03”S, 35°42’52”W, 570 m, 24.07.2024, D. Belo & E. Barbier 742 ( PEUFR!); GoogleMaps Ibid., 550 m, 27.08.2024, R. Silva et al. 10 ( EAN!). GoogleMaps

Conservation status: According to IUCN criteria, despite occurring in an anthropic area, we consider the conservation status of I. buriliae as Data Deficient (DD) since it is known only from the type locality.

Taxonomic notes: Ipomoea buriliae resembles several species found in northeastern Brazil, such as I. alba L. and I. marcellia Meisn. , which share characteristics like a white corolla, prominent veins on the leaf blade, and indumentum on the stem, leaves, petiole, and peduncle. However, reproductive characters play a significant role in distinguishing these taxa, particularly corolla shape, the color of the abaxial mesopetal region, and sepal shape (see Table 2 View Table 2 ).

Anatomical notes: In the paradermic section and the frontal view, the epidermis of I. buriliae presents cells with straight anticlinal walls on the adaxial surface ( Fig. 4a View Fig ), and sinuous on the abaxial surface ( Fig. 4b View Fig ), with druses restricted to the adaxial surface ( Fig. 4a View Fig ). The distribution of stomata is amphihypostomatic, with paracytic and anisocytic stomata and stomatal grouping ( Fig. 4c View Fig ). Tector and glandular trichomes occur on both epidermal surfaces ( Fig. 4a & b View Fig ). In cross-section, the epidermis is uniseriate ( Fig. 4d View Fig ), with oval to rectangular cells and external periclinal walls covered by a smooth cuticle. The leaf blade has an asymmetric dorsiventral mesophyll ( Fig. 4d View Fig ), presenting biseriate palisade parenchyma and spongy parenchyma 1-3 stratum seriate. Also in the mesophyll, idioblasts containing druses ( Fig. 4e View Fig ), laticiferous canals ( Fig. 4f View Fig ), and prismatic crystals in the palisade parenchyma were observed ( Fig. 4f View Fig ). The main midrib, in cross-section, exhibits a biconvex contour ( Fig. 4g View Fig ), prominently wider on the abaxial surface. The epidermis is uniseriate, with tector trichomes. Underlying the epidermis is the lacunar collenchyma ( Fig. 4h View Fig ). Further internally, the fundamental parenchyma consists of isodiametric circular cells with laticiferous canals ( Fig. 4h View Fig ). The vascular system is bicollateral, consisting of a single U-shaped central bundle ( Fig. 4g & i View Fig ). The petiole in cross-section presents a concave-convex contour ( Fig. 4j View Fig ). The epidermis is unstratified with nectar trichomes and sessile peltate glandular trichomes. Adjacent to the epidermis, the cortical region consists of layers of angular collenchyma with druses ( Fig. 4k View Fig ), followed by the fundamental parenchyma with laticiferous canals. The vascular system is bicollateral, composed of five bundles – three central ones forming an arch and two adaxial accessories( Fig.4j View Fig ). Druses occur abundantly in the internal and external regions of the phloem ( Fig. 4l View Fig ). The leaf anatomy of I. buriliae was compared with I. parasitica , which is morphologically similar. Both species exhibit distinct vegetative morphoanatomical characters that are crucial for their delimitation. These include differences in the sinuosity of the anticlinal walls on the epidermal surface of the leaf blade, stomatal types, the number of palisade parenchyma layers in the mesophyll, the type of collenchyma in the midrib, and the shape and number of vascular bundles in the petiole ( Fig. 5 View Fig , Table 3 View Table 3 ).

SEM images of the leaves reveal a diverse array of surface structures. The images of the leaf blade and petiole highlight the abundant presence of tector trichomes ( Fig. 4m & n View Fig ), which appear as thin, elongated projections. Sessile peltate glandular trichomes are distributed across the leaf blade, petiole, and stem ( Fig. 4o–q View Fig ). Spiny projections were observed on the stem ( Fig. 4r View Fig ), characterized by a robust, pointed structure with a broad base that tapers to a sharp tip. SEM images also show the presence of cuticular waxes on the adaxial surface of the leaf blade, appearing as granules ( Fig. 4m View Fig ) and membranous platelets ( Fig. 4r View Fig ).

Palynological notes: The pollen grains of I. buriliae are monads, apolar and very large (x = 110.8 × 109.6 μm), with a spheroidal shape. They are pantoporate containing approximately 90 circular pores (x = 7.1 μm), and lack an annulus. The exine is tectate, echinate, and perforate featuring bulbous spines (x = 15 μm), numbering around 165. These spines have a rounded apex, with a wide, polygonal base. The nexine is thicker than the sexine, and the exine is thin (total exine x = 7.2 μm; sexine x = 3.3 μm; nexine x = 3.95 μm) ( Fig. 6 View Fig , Table 2 View Table 2 ).

Cytogenetic notes: Ipomoea buriliae has a chromosome number of 2n = 30. Distinct GC-rich heterochromatic regions are observed on different chromosomes, forming 14 terminal CMA + /DAPI - bands ( Fig. 7 View Fig ).