Harpalyce greuteri (Leguminosae: Brongniartieae), a new species from eastern Cuba, with a synopsis of and key to the Cuban species of the genus

Abstract: Harpalyce greuteri is described as a new species from the serpentine outcrops of Holguín in eastern Cuba. It differs from other Cuban species of the genus by having leaflets alternate along the rachis, an elliptic, rounded or slightly acuminate standard petal, mostly black keel petals and broadly linear wing petals. An illustration and a distribution map of the new species are presented, as well as a synopsis of and an identification key to all 14 recognized species of H. sect. Cubenses. Lectotypes are designated for nine species names in Harpalyce. Citation: Rankin Rodríguez R. & González Gutiérrez P. A. 2021: Harpalyce greuteri (Leguminosae: Brongniartieae), a new species from eastern Cuba, with a synopsis of and key to the Cuban species of the genus [Novitiae florae cubensis No. 55]. – Willdenowia 51: 209–219. Version of record first published online on 28 June 2021 ahead of inclusion in August 2021 issue.

Phylogenetic studies (e.g. Queiroz & al. 2010Queiroz & al. , 2017 place the monophyletic Harpalyce as the sister group to Tabaroa L. P. Queiroz & al. plus Amphiodon Huber in Brongniartieae, a geographically disjunct tribe comprising a group of tropical American genera along with a group of Australian genera (Ross & Crisp 2005) and the African Haplormosia (Cardoso & al. 2017). The number of Harpalyce species has increased substantially since Arroyo's (1976) monograph, which recognized 20 species. Field work and herbarium studies have added newly described species. Currently there are 210 Rankin Rodríguez & González Gutiérrez: Harpalyce in Cuba eight species recognized in Mexico and Mesoamerica (São-Mateus & al. 2018b), 12 in Brazil (São-Mateus & al. 2016, 2018a, 2019 and 14 in Cuba (Borhidi & Muñiz 1977, updated here), so that the total number of Harpalyce species is now 34. Arroyo (1976) recognized three sections in Harpa lyce: H. sect. Harpalyce (Mexico and Mesoamerica), H. sect. Brasilianae Rydb. (Brazil) and H. sect. Cubenses Rydb. (Cuba). She commented that the Cuban representatives, i.e. H. sect. Cubenses, are characterized by minute, thick bracteoles that are inserted on the pedicel at least 1 mm beneath the calyx, while the flowers exhibit an extraordinary variation in shape, size and texture. The Cuban species show a great diversity in petal colour ( Fig. 1). Arroyo (1976) recorded seven species from Cuba. Borhidi & Muñiz (1977), who did not refer to the work of Arroyo (1976), recognized 17 Cuban species. The Cuban Harpalyce grow in all three Cuban phytogeographic subprovinces: western, central and eastern Cuba (Borhidi 1991(Borhidi , 1996, but most of them are endemic to serpentine outcrops (or rarely to limestone) of what we here consider as northeastern Cuba, extending from Sierra de Nipe (Holguín Province) to Baracoa (Guantánamo Province), and typically growing in the formations known as "cuabales" and "charrascales" (xeromorphic, thorny or sub-thorny thickets on serpentine soils) (Arroyo 1976;Borhidi & Muñiz 1977;Capote & Berazaín 1984;Borhidi 1991Borhidi , 1996. In eastern Cuba, only two species are not exclusive to serpentine subsoil: H. maisiana León & Alain (from southeastern Cuba) grows only on soils derived from limestone, while H. nipensis Urb. has populations growing on serpentine and limestone substrates. Northeastern Cuba is characterized by extensive serpentine outcrops, of c. 1 million to c. 30 million years of age, which form "islands" separated by geographic barriers, such as rivers, and different kinds of substrates, such as limestone. The geological diversity of Cuba, among other factors, is believed to be a major cause of the island's floristic diversity, which is particularly high in northeastern Cuba, the area that has the highest number of Cuban endemics (Borhidi 1991(Borhidi , 1996. In 2009, a Harpalyce population located near Bahía de Naranjo was studied, but all plants were sterile, as were other collections from the same and neighbouring localities of the serpentine outcrops of Holguín Province. In May 2019, the Bahía de Naranjo population was encountered in flower for the first time ( Fig. 2) and in June 2021, in fruit. The flowers, when studied morphologically and compared with specimens and photographs of all other Harpalyce species stored in Cuban herbaria, confirmed that the Bahía de Naranjo plant was an undescribed species. Here we revise the published information on Harpalyce in Cuba. The new species is described below and its differences from other Cuban species are set out, and a synopsis of and an identification key to the 14 Cuban species is presented.
About 170 specimens (including duplicates) of Cuban Harpalyce housed in the Cuban herbaria BSC, HAC, HACC, HAJB, HMC and at the herbarium of the Botanical Garden of Holguín (lacking a herbarium code) were studied, particularly the type specimens in HAC and HAJB. Duplicates of some materials housed in HAJB were also seen in B and PAL-Gr. Images of other specimens (including types) belonging to the collections of A, F, GH, GOET, JE, K, MO, NY, P, S, UC and US were consulted online or as photographs sent by the curators of some of the herbaria. Herbarium codes follow Thiers (2019+). For information about all specimens seen, see Appendix 1 in the Supplemental content online.
Distribution, ecology and conservation status -Har palyce greuteri is a narrow endemic of the phytogeographic Holguin district (districto holguinense, Borhidi 1991Borhidi , 1996, in the province of Holguín in eastern Cuba (Fig. 4). It has been collected on the serpentine outcrops located east of Bahía de Naranjo, El Mocho, El Paraíso, Las Margaritas and San Marcos de Aura, in the municipalities of Báguanos, Gibara, Holguín and Rafael Freyre (Fig. 4, and see details in Appendix 1). The species occurs in xeromorphic, thorny thickets on serpentine bedrock, a formation known as "cuabales" in Cuba (Capote & Berazaín 1984), at elevations from 10 to 150 meters above sea level.
The recently sampled population of Harpalyce greu teri, located east of Bahía de Naranjo, comprises approximately 50 mature and immature individuals growing by a path that leads to a restaurant (conuco de Mongo Viña). Associated species include other Cuban endemic small trees or shrubs: Buxus L. spp., Catesbaea Gronov. spp., Guettarda echinodendron C. Wright, Poitea Vent. sp., Stenostomum aristatum Britton and Tabebuia trachycar pa (Griseb.) K. Schum. This is a tourist area and the whole population is potentially at risk from building work.
We also visited the other four areas where Harpalyce greuteri was previously collected, with the aim of accurately locating plants of the new species. San Marcos de Aura was visited in February 2020, but no plants of H. greuteri were found in the patches of "cuabales" oc-Willdenowia 51 -2021 curring there, which had been partially affected by selective logging and grazing. The locality El Paraíso was explored in September 2020; the whole area had been seriously damaged by fire and, unfortunately, we did not find a single plant of H. greuteri in the surviving patches of thicket. The localities Las Margaritas and El Mocho were explored in October and November 2020; in both places, the "cuabales" vegetation covers extensive areas and is well preserved, but, although several narrow en-demics of Holguín's serpentine outcrops were seen, we did not spot any plants of H. greuteri. We surmise that the species has disappeared at El Paraíso due to human activities including fire, and it may have disappeared from San Marcos de Auras due to the effects of human impact. The good state of preservation of the vegetation at the localities Las Margaritas and El Mocho suggests that the species might survive there but, if so, it is very restricted in its distribution. The distribution area of the species is very fragmented, and apparently very reduced from its former extent. The area of occupancy (AOO) in Bahía de Naranjo, where approximately 50 individuals occur, is less than 2 km 2 . At the localities El Paraíso and San Marcos the species probably no longer exists. We estimate that in the other two well-preserved localities Las Margaritas and El Mocho there could be a similar number of plants as at Bahía de Naranjo, and we predict that the total number of surviving individuals of Harpalyce greuteri is approximately 150 and that the AOO in these two other well-preserved localities is each less than 2 km 2 . Applying IUCN conservation assessment criteria (IUCN 2017), H. greuteri can be considered Endangered (EN) under the criteria B1ab (i,ii,iii,iv,v)+2ab(i,ii,iii,iv,v). The existence of H. greuteri together with other narrowly restricted Cuban endemics, mentioned above, on this small patch of serpentine outcrop, deserves urgent conservation attention.
Etymology -The specific name honours Werner Greuter, supporter of investigations into the Cuban flora for over 20 years. He has contributed to more than 20 fascicles of Flora de la República de Cuba and is co-author of Vascular plants of Cuba: a preliminary checklist (Greuter & Rankin Rodríguez 2017 [Grisebach, 1866: 71;Urban 1926: 356] and H. macrocarpa [see Fig. 1A]). The black keel and partially black wings of H. greuteri have not been seen in flowers of H. macrocarpa, H. suberosa (Fig. 1A, B) H. suberosa (Fig. 1A, B)

General comments on Cuban Harpalyce species
The first species of Harpalyce described from Cuba was H. cubensis (Grisebach 1866). Five other species were subsequently described, two by Britton (1920) and three by Urban (1926). Urban (1926: 359), stated that unfortunately it was impossible to identify most of the specimens collected and sent from Cuba by Ekman, because they had been collected without flowers. He added that, due to the reduced number of leaflets, these sterile specimens did not fully match H. cubensis, and wondered whether they might perhaps correspond to new species. Among Fig. 4. Distribution of Harpalyce greuteri. The red dots indicate the localities where the species was previously collected but not relocated during our field work. The blue diamond indicates Bahía Naranjo, the type locality where the species has been relocated. Willdenowia 51 -2021 the sterile specimens collected by Ekman is the one collected at El Paraíso, Holguín (Ekman 7601), which is here identified as H. greuteri.
León & Alain (1950) described three more species, based on specimens with inflorescences, flowers and fruits, except for Harpalyce angustiflora León & Alain that lacked fruits. In the second volume of their Flora de Cuba, León & Alain (1951) recognized all nine previously described species. León & Alain (1951: 303) also commented that the sterile specimen León 11971 (HAC) collected at "Alto de la Mesa de Prada, Jauco, Oriente" (southeastern region of Cuba), with flexuous leaves and 27 leaflets per leaf evidently belongs to Harpalyce, but they never described that material as a new taxon.
Arroyo ( While recognizing the close morphological similarity of Harpalyce suberosa with H. cubensis, we refrain from synonymizing them. In Cuban herbaria (HAC, HAJB) there are many specimens collected in Matanzas Province, often with flowers or fruits, that agree with the original description of H. suberosa and match the lectotype specimen of that name. There are also several specimens, collected in the locality Cajálbana in Pinar del Río Province, that show the species characteristics presented in the protologue of H. cubensis and match its lectotype specimen (C. Wright 2303, GOET #5024). Having compared the H. cubensis specimens from Pinar del Río Province with those identified as H. suberosa from the Matanzas and adjoining Mayabeque and La Habana Provinces, we note that H. cubensis has leaflets less ferruginous abaxially. A microscopic study of the abaxial leaflet surface showed that in H. suberosa the glands are much more abundant and more densely packed than in H. cuben sis. Based on this difference, the discrete distributions and the morphological differences mentioned by Urban (1926: 357), we chose to maintain H. suberosa and H. cubensis as distinct species. Further field work, focused on the study of flowers, as well as molecular studies, will help to clarify their relationship. Arroyo (1976) added data for, and improved the descriptions of, most of the species she recognized in her treatment; however, her description of Harpalyce maisi ana is not fully accurate, because it includes characters of the specimen León 11971 (NY), which is an isotype of H. flexuosa, a different species (see below). Borhidi & Muñiz (1977) also published a sizeable contribution on Cuban Harpalyce. They described eight new species, two varieties and a forma, and accepted all Cuban species previously described. Their account includes a total of 17 species. They were probably unaware of, and did not cite, Arroyo's (1976) Borhidi & Muñiz's (1977) sterile species, which shows obvious similarities with H. flexuosa and likely represents the same taxon. The third sterile species described by Borhidi & Muñiz (1977) is H. moana Borhidi & O. Muñiz, known only by the holotype specimen at HAC. This is a very weakly defined species, which in its sterile state cannot be reliably distinguished from the morphologically similar H. baracoensis Borhidi & O. Muñiz and H. villosa Britton & P. Wilson and is likely conspecific with one of them. We here provisionally treat H. moana as a synonym of H. baracoensis. Field work in the area of the locus classicus of H. moana, the former Potosí Mine, now severely degraded by mining, will hopefully result in the discovery of plants with flowers and/or fruits so as to test our hypothesis of synonymy.
In conclusion, we recognize 14 species of Harpalyce in Cuba. We refrain from recognizing any infraspecific taxa, although some were previously proposed, because more field work to collect material with flowers and fruits and, if possible, molecular studies are required to assess infraspecific taxon limits in Cuban Harpalyce.
Most Cuban Harpalyce species (11 out of 14) are endemic to northeastern Cuba where it is frequent to find two or more species growing in the same area; whereas only four species (H. cubensis, H. greuteri, H. macro carpa and H. suberosa) grow in other parts of Cuba, from the eastern central region to the west, and have distribution areas that do not overlap.