Sisällysluettelo: :: Library Catalog

Tallennettuna:

Bibliografiset tiedot
Päätekijät:	Meyer, Fabrício Schmitz, Yamamoto, Manuella Aparecida Cosmo Galan, Goldenberg, Renato
Aineistotyyppi:	Recurso digital
Kieli:
Julkaistu:	Zenodo 2025
Aiheet:	Biodiversity Taxonomy Animalia Porifera Demospongiae Tetractinellida Pleromidae Pleroma Pleroma venosum
Linkit:	https://doi.org/10.5281/zenodo.18987630
Tagit:	Lisää tagi Ei tageja, Lisää ensimmäinen tagi!

Sisällysluettelo:

Pleroma × venosum F.S.Mey. & M.A.Yamam. nothosp. nov. (Figures 1, 2, and 4G–I).Type: — BRAZIL. Rio de Janeiro: Paraty, Parque Nacional Serra da Bocaina, Pedra da Macela, 23° 08’ 22” S, 44° 48’ 49” W, 1,800 m, 24 March 2022, M.A. Yamamoto 94 (holotype: UPCB!; isotypes: CTBS!, RB!, SP!).Diagnosis:— Pleroma × venosum shows intermediate characters between Pleroma sellowianum and Pleroma echinatum. It differs from P. sellowianum mainly by the leaves with 5 veins (vs. 3 veins in P. sellowianum), inflorescences with groups of 3–5(–7) flowers (vs. solitary flowers), petals with a permanently lilac color at the beginning of anthesis (vs. white changing to pink at anthesis), and appendages of the pedoconnective in both stamen whorls yellow in flowers at anthesis (vs. white or cream). It differs from P. echinatum mainly by having a larger hypanthium (6–7 × 4.5–6 mm vs. 5–6.5 × 4–4.5 mm in P. echinatum), and sericeous (vs. setose), besides antesepalous anthers with thecae cream, speckled with light purple during anthesis (vs. entirely purple; see Figures 4C and 4I).Description:— Erect shrubs 0.6–1.5 m tall, with sympodial growth, strongly branched.Younger branches subcylindrical to quadrangular, moderately strigose, trichomes 0.3–0.6 mm long, unbranched, eglandular, appressed, the base linear, superficial, unforked; the older branches basally decorticating, brownish; nodes slender. Leaves chartaceous, petioles 3.5–7 mm long; blades 2.5–5 × 1.2–2.2 cm, slightly discolorous, narrowly ovate or elliptic, base obtuse, apex acute, margins slightly crenulate, moderately strigose, trichomes 0.6–1 mm long, unbranched, eglandular, appressed, the base linear, superficial, unforked, 5 acrodromous veins, basal, domatia absent, reticulation formed by the secondary and tertiary veins conspicuous on the abaxial surface; abaxial surface flat, pale-green on fresh specimens and brownish on dry specimens, moderately short-strigose on surface and secondary veins, trichomes 0.2–0.4 mm long, unbranched, eglandular, appressed, the base linear, superficial, unforked, moderately strigose on primary veins, trichomes 0.4–0.8 mm long, unbranched, eglandular, appressed, the base linear, superficial, unforked, adaxial surface flat, rugose, dark green in both fresh and dry specimens, moderately scabrous, trichomes 0.2–0.8 mm long, unbranched, eglandular, appressed, the base wide, superficial, unforked, followed by a sequence of white dots. Simple or compound dichasium, 2–4 × 2–3.5 cm, terminal, 3–5(–7) flowers, axis quadrangular, with the same indumentum as the branches; bracts in pairs, chartaceous, petioles 0.8–2 mm long, leafy, blades 1.2–2.8 × 0.4–1.2 cm, slightly discolorous, ovate or elliptic, base obtuse, apex acute, margins slightly crenulate, 5 acrodromous veins, with the same indumentum as the leaves on both surfaces; bracteoles in pairs, green to reddish-green on living specimens, brown on dehydrated specimens, early deciduous, 8.5–10 × 6.5–7.5 mm, oblong, apex obtuse or retuse, becoming emarginate with the growth of the flower bud, slightly covering the apex of the flower bud, margins slightly crenulate, moderately pilose, trichomes 0.2–0.5 mm long, unbranched, eglandular, erect, the base linear, superficial, unforked; abaxial surface moderately strigose, indumentum restricted to the central portion of the surface, glabrous at the margin and near it, larger trichomes in its central portion, decreasing in size towards the margin, trichomes 0.2–1 mm long, unbranched, eglandular, appressed, the base linear, superficial, unforked, adaxial surface glabrous. Flowers 5(–6)-merous, pedicels 0.6–1 mm long; hypanthium, 6–7 × 4.5–6 mm, obovate, ecostate, densely sericeous, trichomes 0.5–1.8 mm long, unbranched, eglandular or rarely mixed with glandular trichomes, appressed, the base linear, superficial, unforked; sepals early deciduous, 6.5–7.5 × 3.5–4 mm, obovate, apex rounded or truncate, margins moderately pilose, trichomes 0.5–1 mm long, unbranched, eglandular, appressed, the base linear, superficial, unforked; abaxial surface with the same indumentum as the hypanthium, with trichomes restricted to the central portion of the surface, glabrous at the margins and near it, larger trichomes in its central portion, adaxial surface glabrous; petals 29.5–32.5 × 21.5–25.5 mm, obovate, apex obtuse, apiculate, becoming retuse or slightly emarginated near senescence, lilac during anthesis or lilac with a red base on senescent flowers, with venation that is more intensely colored than the blade, glabrous in both surfaces, margin moderately pubescent, trichomes 0.1–0.3 mm long, unbranched, eglandular or glandular (often mixed), erect, the base linear, superficial, unforked; stamens 10(–12), dimorphic, antesepalous with white filaments on the basal two-thirds and lilac on the upper third during anthesis, turning completely dark pink in senescent flowers, 8.5–10 mm long, sparsely pilose on its middle third, trichomes 0.7–1.2 mm long, unbranched, glandular, curved, the base slightly broadened, pedoconnective cream to slightly light purple during anthesis, turning completely dark pink in senescent flowers, prolonged 3–4 mm below the thecae, glabrous, ventral appendages bilobed, yellow, patent, apex obtuse, ca. 0.7 mm long, glabrous, thecae cream, speckled with light purple during anthesis, brownish on senescent flowers, 9.5–10 × 0.8–1 mm, falcate, antepetalous with white filaments on the basal two-thirds and lilac on the upper third during anthesis, turning completely dark pink on senescent flowers, 6.5–7 mm long, sparsely pilose on its middle third, trichomes 0.5–1 mm long, unbranched, glandular, curved, the base slightly broadened, pedoconnective yellow during anthesis, turning brownish in senescent flowers, 0.8–1 mm prolonged below the thecae, glabrous, ventral appendages bilobed, yellow, patent, apex obtuse, ca. 0.5 mm long, glabrous, thecae yellow during anthesis, brownish on senescent flowers, 7–7.5 × 0.8 mm falcate; ovary 5.8–6 × 3.8–4.2 mm, 5(–6)-locular, apex densely sericeous, trichomes 0.3–1 mm long, unbranched, eglandular or glandular (seldom mixed), erect or curved, the base linear, superficial, unforked; style lilac on its basal three-quarters and white on its apical quarter during anthesis, turning completely dark pink on senescent flowers, 12.5–15 mm long, apex curved, glabrous, stigma truncate. Capsular fruits 8.5–10 × 7.5–8.2 mm, cupuliform, sepals early deciduous, epicarp undivided when mature, ecostate. Seeds ca. 0.8 × 0.2 mm, cochleate, with a tuberculate testa.Paratypes:— BRAZIL. Rio de Janeiro: Paraty, Parque Nacional da Serra da Bocaina, 23° 08' 22” S, 44° 48' 49” W, 10 March 2023, M.A. Yamamoto 142 (UPCB!); ibidem, 23° 08' 22''S, 44° 48' 49'' W, 10 March 2023, M.A. Yamamoto 143 (CTBS!); cume da Pedra da Macela, 23° 08' 23” S, 44° 48’ 50” W, 30 March 2024, F.S. Meyer & M.L. Brotto 2792 (MBM!, RB!, SP!, UPCB!).Distribution and habitat:— Pleroma × venosum is known from a single locality, at the highest point of Pedra da Macela, near the “Mirante Norte,” in the municipality of Paraty, state of Rio de Janeiro (Figure 3). The collection site is a small area with High-Altitude Grasslands (“campos de altitude” according to the classification by IBGE 2012), restricted to the highest part of the mountain (Figure 2L). There are few mountains in this part of the range with rocky outcrops and similar environments. However, one nearby peak, “Pico dos Dois Frades” seems to have areas like those where we found P. × venosum. Due to the difficulty of accessing the site, as there are no trails, we were unable to search it for potential populations of the hybrid in the surrounding area. This area warrants further exploration for insights into the distribution and habitat preferences of P. × venosum.Phenology:—Flowers and fruits were observed only in March. Pleroma × venosum occurs sympatrically and flowers synchronously with both P. sellowianum (4D–F), which forms large populations in the highest areas of Pedra da Macela, and with P. echinatum (4A–C), which is also quite common, although less abundant than the former.Conservation status:— Pleroma × venosum is known from only two living plants, which were collected on different dates, and resulted in four herbarium samples. The samples Yamamoto 94 (collected in 2022), Yamamoto 143 (2023), and Meyer & Brotto 2792 (2024) all derive from a single individual. Another specimen, Yamamoto 142, was collected in 2023 from a second individual found nearby.It was not possible to estimate its Area of Occupancy or Extent of Occurrence and apply Criterion B in the risk assessment for this taxon, as there are only two known distribution points, making it impossible to define the necessary polygon for the calculation. Based on Criterion D, which is the most applicable due to its small and highly reduced populations, P. × venosum, with fewer than 50 mature individuals, can be classified as Critically Endangered [CR: D] according to IUCN (2022).It occurs inside the Parque Nacional da Serra da Bocaina, a fully protected conservation area with several restrictions to human activities. Despite this, the sites where we found specimens are near trails accessed by visitors, who may trample them—or even their seedlings—or start fires, especially during dry periods, as the area is also frequently used as a camping spot.Etymology:—The epithet “ venosum ” was chosen to highlight a striking characteristic of this taxon: the welldefined venation of the petals. The term “ venosum ” comes from the Latin word “ venosus ”, meaning veined or having veins (Stearn 1985).Notes:— Pleroma × venosum occurs sympatrically with five other species of the genus at Pedra da Macela. However, it appears to have closer morphological affinities with two of them, which are likely its parent species. Pleroma × venosum is interpreted here as a hybrid between P. sellowianum and P. echinatum, showing clear intermediate vegetative and floral characters between these species (Figure 4). Both P. sellowianum and P. echinatum, as well as P. × venosum share the same habitat and flower synchronously at Pedra da Macela.Morphologically, P. × venosum shares with P. sellowianum, the elliptical leaves, although P. × venosum may have narrowly ovate ones. The petioles are conspicuous, 3.5–7 mm in P. × venosum and 3.5–6 mm in P. sellowianum. Additionally, both species have strigose abaxial leaf surfaces. The hybrid also resembles P. sellowianum in its bracteoles (bracts in P. sellowianum, as its flowers are solitary); in both species these structures are brownish, and the indumentum is restricted to the central portion of the bracteole’s abaxial surface. Finally, both species also share a sericeous hypanthium and sepals (Figures 4E and 4H), pilose filaments in the median third (in both stamen whorls), a glabrous style, and petals with venation that is more intensely colored than the blade (Figures 4D, 4G). Despite these similarities, P. × venosum differs from P. sellowianum by the diagnostic characters mentioned above and by having only two bracteoles protecting the flower bud (vs. six in P. sellowianum), as well as slightly larger petals, 29.5–32.5 × 21.5–25.5 mm (vs. 23.5–28 × 17.5–20.5 mm).Pleroma × venosum shares with P. echinatum the narrowly ovate leaves (although in P. × venosum they may also be elliptical) with five veins, a moderately scabrous adaxial surface (although in P. echinatum the trichomes have a wider base than those in P. × venosum), an evident reticulation formed by the secondary and tertiary veins on the abaxial surface, and conspicuous petioles, 3.5–7 mm in P. × venosum and 4–8 mm in P. echinatum. Additionally, in both species, the venation of the petals is more intensely colored than the blade (Figures 4A and 4G), and the appendages of the pedoconnective in both stamen cycles are yellow in flowers at anthesis (Figures 4C and 4I). Pleroma × venosum differs from P. echinatum by the diagnostic characters mentioned above and by the rugose adaxial surface of its leaves, covered by trichomes 0.2–0.8 mm long (vs. bullate leaves covered by trichomes 0.6–1.4 mm in P. echinatum), as well as larger petals, 29.5–32.5 × 21.5–25.5 mm (vs. 13.5–15.5 × 11–12 mm).Finally, it resembles Pleroma curucutuense Meyer & Goldenberg (2023: 91), a species that does not occur near Pedra da Macela but shares several traits with P. × venosum. These include elliptical leaves (although they may also be narrowly oval in P. × venosum), dichasial inflorescences with a reduced number of flowers 3–5(–7) in P. × venosum and 3–7(–9) in P. curucutuense —and two bracteoles with the apices slightly covering the floral bud. Both species also have sericeous hypanthium and sepals, and they inhabit high-elevation grasslands. They differ from each other in that P. × venosum has 5-veined leaves (vs. 3-veined leaves in P. curucutuense), petals lilac in flowers at anthesis (vs. purple), the filaments of the antesepalous stamens are sparsely pilose along the middle third (vs. glabrous or sparsely pilose in the basal portion), and the appendages of the connective in both cycles are yellow (vs. light purple).We provide below an identification key for the taxa of Pleroma that occur at Pedra da Macela to facilitate the recognition of P. × venosum.

Samankaltaisia teoksia