An appraisal of the Mozambique types and endemic taxa in the Pires de Lima plant collection at the Porto Herbarium (PO, MHNC-UP)

Putative type specimens of 18 taxa described from Mozambique collected by Américo Pires de Lima at the beginning of the 20 th century are kept in the African collections of the Herbarium of Porto (PO) at the MHNC-UP. These specimens were not collected as part of a dedicated scientific mission, but they and the scientific studies carried out by Pires de Lima represent an important contribution to Portuguese colonial projects. During his scientific career, and despite the lack of support and specialised literature, Pires de Lima described 17 species new to science. In this work we analysed part of the material collected by Pires de Lima, kept in PO at MHNC-UP. Today, only two of the 17 taxa described by Pires de Lima remain as accepted taxa, viz. Tephrosia reptans var. microfoliata (Pires de Lima) Brummitt and Crotalaria retusa var. tunguensis (Pires de Lima) Polhill. In addition, information on Polygala limae Exell, named after Pires de Lima, has also been analysed as this is still accepted. Of over 300 specimens collected by Pires de Lima in the early 20 th century, some 40% remain unidentified due to lack of expertise. Undoubtedly, this collection contains many other promising specimens in need of revision, taxonomic update, and other novelties that can be found even in the more ancient and inconspicuous materials.


Introduction
Mozambique is a botanical hotspot with five phytogeographic regions organised into communities of miombo, mopane, undifferentiated woodland and coastal mosaic (Burgess et al. 2004).In recent years, several centres of plant endemism have been recognised in Mozambique, with new taxa described at a significant rate.Mozambique includes four cross-border centres of botanical endemism, namely the Rovuma Centre, encompassing northeastern Mozambique and southeastern Tanzania (Darbyshire et al. 2019), where the province of Cabo Delgado is located, from which the botanical specimens discussed here originate.
Recent checklists of the flora of Mozambique, based on published literature, online databases and herbarium collections, recognise 5 957 species plus 605 subspecies and 537 varieties belonging to 226 families and 1 746 genera (Odorico et al. 2022).Initiatives such as the International Union for Conservation of Nature-Species Survival Commission (IUCN-SSC) Southern African Plant Specialist Group to update plant species assessments in the 2017-2020 period, and the 'Tropical Important Plant Areas: Mozambique' project, have been developed to raise awareness of the importance of Mozambique's flora (Darbyshire et al. 2019).A thorough assessment for Mozambique carried out in 2021 included 1 667 of the recorded taxa on the IUCN Red List (Odorico et al. 2022).
At the beginning of the 20 th century, scientific research in Portuguese colonies witnessed a change in attitude towards the Portuguese model of colonisation, largely due to international pressure that promoted a shift from the occupation of colonial territories by 'historical right' to 'effective occupation' (Neto 2013;Pires & Fogarty 2014).These changes, reinforced by the Berlin Conference of 1884/5, required a deeper scientific knowledge of the colonised territories.The scientific investigations carried out by Américo Pires de Lima in Mozambique between 1916/17 in the Cabo Delgado Province (Pires de Lima 1933), although not strictly a scientific mission, can be placed within this paradigm of the Portuguese colonial project.
The Herbarium of the University of Porto (PO) founded in 1892, is at present part of the Natural History and Science Museum of the University of Porto (MHNC-UP) (Folhadela et al. 1993;Vieira & Viegas 2019).With almost 130 000 specimens, it is one of the three largest herbaria in Portugal.In addition to the Portuguese flora, PO houses collections of the flora of former Portuguese colonies.These include a Mozambique collection, with specimens collected by various collectors some 50 to 100 years ago.As with other African collections, they remain as the institution's backlog due to lack of expertise for identification.
Among the specimens from the PO African herbarium is the collection of Américo Pires de Lima (1886-1966), a medical doctor, professor, botanist, bacteriologist and researcher.As an academic, he was a major figure at the University of Porto, where he held prominent positions including Director of the Faculty of Sciences and the Faculty of Pharmacy at the University of Porto and the Institute of Botany (Salema 1989).In 1916, still at the beginning of his academic career at the Faculty of Sciences, he was mobilised for World War I as a lieutenant doctor in an expedition to Mozambique, and also head of the Hygiene and Bacteriology Section (Pires de Lima 1933).Although this was a military mission, Pires de Lima was commissioned by two professors from the University of Porto, and reinforced by a ministerial decree, to take advantage of the trip to Mozambique to carry out studies on the flora, fauna and anthropology of the region where he was stationed, without disruption to his military service (Salema 1989).
Although Pires de Lima was not an expert in African botany, he endeavoured to collect in Mozambique, to analyse some of this material and to proceed with the identification of some of the specimens.He did this without an adequate specialised library and, according to his testimony, identified specimens by comparison (Pires de Lima 1950).The classification process was partly carried out with the help of Gonçalo Sampaio (1865-1937;University of Porto) andJúlio Henriques (1838-1928; University of Coimbra) (Pires de Lima 1921), the two best-trained botanists in Portugal at the time.It is also known that Pires de Lima intended to send the specimens to experts at Kew (Pires de Lima 1950).Some of the Pires de Lima specimens are type specimens of lichens or vascular plants from Mozambique referred to in the works of Vainio and Pires de Lima (Vainio 1930;Pires de Lima 1921, 1922, 1924;Paz-Bermúdez 2004), published in the Portuguese scientific journals available at the time, which contained much taxonomic content (Boletim da Sociedade Broteriana and Brotéria journals).Pires de Lima is known to have published at least 20 vascular plant names during the period between 1921 and 1924 (Figueiredo et al. 2018).
Initiatives such as Flora Zambesiaca and the work evaluating endemism in Mozambique and the checklist of Vascular Plants of Mozambique (Mendonça & Wild 1960, Darbyshire et al. 2019, Odorico et al. 2022), allowed us to verify that the locations of Pires de Lima's collections correspond to areas that were little-known to European botany, which highlights the value of these collections.
Currently, the coastal region of the province of Cabo Delgado is identified as having high botanical value in the country and is recommended as a strategic conservation priority (Odorico et al. 2022).Added to this fact are the current scenarios of armed conflict, affecting the lives of populations and also resulting in the destruction of habitats.Pires de Lima's collection from a period of about 100 years ago, covers different types of habitats, and constitutes an important reference of the region's previous floristic cover, for habitat conservation and restoration projects.
This paper aims to document some of the types of the Mozambique vascular collection housed at PO, and to promote understanding and awareness of the importance of the permanent review of biological collections in systematics.

Materials and methods
The need for taxonomic and nomenclatural adjustments of the PO Mozambican types was identified in the context of an inventory following the project: IAPT REPORT Small Collections Grants -Grant Application (grant round 2019-20: African Backlog at PO Herbarium: uncovering 20 th -century collectors and specimens from unofficial African botanical missions) and studied in the context of work placement (Faria 2021).These two processes made it possible to access PO and to search, organise, photograph or catalogue the African and, in particular, the Mozambican collections.In time, it was possible to complete the recognition of the backlog of collections that had been unrecognised for several decades.We also found that the Pires de Lima collection is accompanied by documentation, such as notebooks with descriptions, inventories and publications and we were able to photograph specimens (Canon EOS 6D MARK II camera).

Results
Of the 324 vascular specimens collected by Pires de Lima, 59% were identified to at least family level, with the most represented families being Fabaceae, followed by Cyperaceae.A total of 175 of these specimens have been identified and published with collector numbers (Pires de Lima 1921, 1922, 1924), but 149 remain unidentified until today.Although there have been some evaluations of specimens in this vascular plant collection by Kew and British Museum staff or researchers (Arthur Wallis Exell, Richard Kenneth Brummitt, Jane Browning, Roger Marcus Polhill) or other sporadic studies by African flora specialists (Jorge Paiva, António Rocha da Torre, Simone Balle, Franciscus Jozef Breteler and Paul Goetghebeur), these types needed a taxonomic revision to support the global databases that still present Pires de Lima names as unresolved.
In total, 18 of the 324 specimens in the collection of Américo Pires de Lima (1921, 1922and 1924) were identified as 'typus' by Pires de Lima or by other authors studying the collection.These type specimens were collected between 1916 and 1917, 16 by Américo Pires de Lima himself and two by his friend, Lieutenant Romualdo Tavares (Pires de Lima 1921, 1922, 1924), also in military service.

Types
The vascular plant specimens from the Pires de Lima collection that have been accessed and studied, and previously marked as types, are the following 18 taxa, listed in alphabetical order by family: Notes: These specimens were initially labelled by Pires de Lima as Pedicellaria glandulosa Pires de Lima (type specimens).However, according to the POWO, Pedicellaria glandulosa Pires de Lima is currently considered an unplaced name that cannot be accepted or synonymised.In 2022, one of the authors of this manuscript (J.Paiva) argues that Pires de Lima misidentified it and identifies it as Cleome gynandra L. (Figure 3).
Distribution: Baphia macrocalyx is native to south of Tanzania and north of Mozambique.
Notes: These specimens were initially labelled by Pires de Lima as Baphia mocimboensis Pires de Lima (type specimens).In July 1964, R.K. Brummitt reviewed the specimens as Baphia macrocalyx Harms.In 2022, one of the authors of this manuscript (J.Paiva) also agreed that Pires de Lima misidentified the specimens, and agreed with R.K. Brummitt, naming them as Baphia macrocalyx Harms (Figure 10).
Distribution: Tephrosia villosa subsp.ehrenbergiana is native to Ethiopia to South Africa, Angola, Namibia and Madagascar.
Distribution: Agelanthus sansibarensis is native to Somalia, Kenya, Tanzania and Mozambique.
Distribution: Hibiscus cannabinus L. is widespread in tropical and subtropical Africa and extending to India (as an introduced species).
Notes: These specimens were initially labelled by Pires de Lima as Hibiscus henriquesii Pires de Lima (type specimens).In 1958, A. Exell, Brummitt reviewed the specimens as Hibiscus cannabinus L. In 2022, one of the authors of this manuscript (J.Paiva) agreed with A. Exell, and maintained the identification as Hibiscus cannabinus L. (Figure 15).
Distribution: Oldenlandia affinis subsp.fugax is native to tropical and South Africa, Comoros and Madagascar.
Notes: These specimens were initially labelled by Pires de Lima as Oldenlandia prostrata Pires de Lima.In 2022, one of the authors of this manuscript (J.Paiva) reviewed the specimen and synonymised to O. affinis, but to the subspecies fugax (Vatke) Verdc., the subspecies of Oldenlandia present in Mozambique (Figure 18).

Discussion
In the Pires de Lima collection, we found specimens marked as types representing 18 taxa names.Among these, only three taxa are presently acknowledged, viz.Exell, Striga diversifolia Pires de Lima, and Tephrosia reptans var.microfoliata (Pires da Lima) Brummitt.However, we found that the type specimen of Striga diversifolia Pires de Lima corresponds to the widely distributed Striga asiatica (L.) Kuntze.
In conjunction with other recent studies such as those by Darbyshire et al. (2019) and Odorico et al. (2022), this paper contributes significantly to the ongoing efforts to update and enhance the accessibility of data concerning the floristic diversity of Mozambique.We also hope this appraisal of the Mozambique types and endemic taxa in the Pires de Lima plant collection at the Porto Herbarium revives the interest in the African collections present at PO Herbarium.
These specimens were initially designated by Pires de Lima as Gloriosa sampiana Pires de Lima (type specimen).According to the POWO, Gloriosa sampiana Pires de Lima is recognised as a synonym of Gloriosa simplex L. Until 2022, no other researcher examined this specimen, which one of the authors of this manuscript (J.Paiva) identified as Gloriosa simplex L. (Figure4).Paiva) also agreed that Pires de Lima misidentified the specimens and agreed with P. Goetghebeur, naming them Bulbostylis contexta.(Figure6).
holo.; iso.).Initially this specimen remained unlabelled by Pires de Lima, who only attributed the name of the family to the specimen (Polygalaceae).In 1956, A. Exell identified the specimen as Polygala limae Exell.In 2000, one of the authors of this manuscript (J.Paiva) reviewed the specimen and agreed with the status of this specimen as the holotype of the name Polygala limae Exell, an opinion he maintains until today.J. Paiva has revisited the region where the type material was collected, but was unable to relocate additional material of P. limae.Polygala limae Exell is very similar to P. goetzei Gürke but appears to be an annual, whereas P. goetzei is a perennial, and has smaller flowers and fruits than P. goetzei.As there is only the type material, more material is needed to assess whether they are two species (Figure17).