Lectotypification of names in Parkia R.Br. (Leguminosae: Caesalpinioideae, mimosoid clade) for Africa and Madagascar

Ten specific names plus those of three varieties, which refer to the four currently recognised species of Parkia in Africa and Madagascar (P. bicolor A.Chev., P. biglobosa (Jacq.) R.Br. ex G.Don, P. filicoidea Welw. ex Oliv., P. madagascariensis R.Vig.), are listed. Their types are enumerated with lectotypes indicated where necessary and in a few cases, a second-step lectotypification is made. Two further names are invalid and illegitimate respectively. Two tables summarise the synonymy of these names according to major flora treatments and revisions of the genus. Connections between the botanist Robert Brown, who established the genus Parkia, and the explorer Mungo Park, after whom Brown named it, are described briefly.


Introduction
The last revision of Parkia R.Br. (Leguminosae: Caesalpinioideae, mimosoid clade) for the African region, some 40 years ago, recognised three native species in continental Africa and one in Madagascar (Hopkins 1983) and this has become the generally accepted taxonomy (e.g. Lebrun & Stork 1992;Lock 1989). All three species on the African mainland (P. bicolor A.Chev. from forest, P. biglobosa (Jacq.) R.Br. ex G.Don from woodland/savanna, P. filicoidea Welw. ex Oliv. from forest) are widespread and morphologically variable and in all cases this variation has a geographical component. Recent studies involving microsatellite data and phylogenetic analyses based on rDNA and pDNA by Ahossou (2022;Ahossou et al. 2020) for the species on the African mainland are likely to lead to the re-evaluation of the species concepts in Hopkins (1983). It is therefore timely to lectotypify the names of these taxa and their current synonyms to aid the selection of appropriate names if more species or subspecies are recognised as a result of Ahossou's work. Table 1 lists the principal names that have been used by different authors to refer to Parkia in Africa and Madagascar and their placement in taxonomic treatments and major flora accounts, especially those written by the legume expert E. G. Baker and by mimosoid specialists such as J. P. M. Brenan and J.-F. Villiers. Many more recent country or local floras and checklists have been published but most are based on the established taxonomy and so are not cited. For the African mainland, nine names that have been validly and legitimately published at species level in Parkia are discussed here, with a further three at varietal level, plus two others that are illegitimate or invalid respectively ( Table 2). In addition to these, several early names that are considered synonyms of P. biglobosa were discussed briefly elsewhere (Hopkins 1983) and are not dealt with again. One further name at species level refers to Parkia in Madagascar.
From the mid 20 th century onwards, all the African names mentioned here were generally regarded as referring to only four species (Baker 1930;Hagos 1962;Keay 1958), later reduced to three by Hopkins (1983), who widened the concept of Parkia biglobosa because of its pattern of continuous variation in a suite of leaf characters. The single species in Madagascar, P. madagascariensis R.Vig., has a limited distribution in forest in the northwest of the island and remained little known until quite recently, when photographs and much better collections became available. Its status as a monomorphic local endemic has not been questioned (Hopkins 1983;Villiers 2002

1949
--  (Brenan 1970) Fl. Gabon = Flora of Gabon (Villiers 1989) Fl. Somalia = Flora of Somalia (Thulin 1993) Leg. Mad. = The Leguminosae of Madagsacar (Villiers 2002) 1999; Mabberley et al. 2022). This course was offered as part of their medical training although students were not obliged to take it. Neither Park nor Brown graduated from the university, probably in part because passing the exams was not a requirement for becoming a medical practitioner at that time (Duffill 1999). Mungo Park's first visit to the tropics was due to the patronage of Sir Joseph Banks, who proposed that he took the position of assistant surgeon on a voyage to Sumatra where he collected and illustrated fish (Duffill 1999). Park then made two expeditions to West Africa to investigate the course of the Niger River and he established definitively for a European audience that it flowed west to east. His first expedition (1795 -1797) was sponsored by the African Association, which was based in London and counted Sir Joseph Banks amongst its founders (Duffill 1999). In the account of his travels, Park mentioned the plant that Brown later named Parkia africana R.Br. (now a synonym of P. biglobosa) as the "nitta tree", describing it as a "species of mimosa" in which the "pods are long and narrow, and contain a few black seeds enveloped in the fine mealy powder before mentioned; the meal itself is of a bright yellow colour, resembling the flour of sulphur, and has a sweet mucilaginous taste: when eaten by itself it is clammy, but when mixed with milk or water, it constitutes a very pleasant and nourishing article of diet" (Park 1799: 336 -337). Parkia biglobosa continues to be a food plant of some importance in West Africa although the semi-fermented seeds, used as a condiment, are more significant than the mealy pulp (Hall et al. 1997).

madagascariensis
Scientific and geographical exploration were strongly inter-related in Britain at this time and a further connection between Brown and Park concerns a voyage of exploration to Australia. Sir Joseph Banks initially invited Park to take part in this expedition but he turned down the opportunity, hoping to return to West Africa. Banks found a replacement for Park in Brown, who sailed to Australia on the Investigator, commanded by Matthew Flinders, in 1801 -1803, and this led to Brown's subsequent immense contribution to the description of the flora of Australia (Mabberley et al. 2022). Park got his wish to return to West Africa, sponsored this time by the British government, although his second expedition (1805 -1806) was not regarded as a success, even though he travelled a considerable distance down the Niger. He died aged just 35 near Bussa rapids on the Niger, in what became Nigeria, most of the other expedition members having already died along the route.
Robert Brown based his description of the genus Parkia partly on material collected in West Africa by another Scotsman, Hugh Clapperton (see below under P. africana). Like Park, he took part in two expeditions to the region and for the first of these (1822 -1825), with Dixon Denham and Walter Oudney, he travelled from Tripoli in Libya to Bornu, now in Nigeria, and back again; this trio became the first Europeans to see Lake Chad. Also, like Mungo Park some 20 years before him, Clapperton (born 1788Clapperton (born , died 1827, perished in Nigeria on his second expedition to West Africa (Clapperton & Lander 1829). According to Brown (1826: 233), P. africana was known in Bornu as "Doura" and its preparation was described by Clapperton as follows: "The seeds are roasted as we roast coffee, then bruised, and allowed to ferment in water; when they begin to be come putrid, they are well washed and pounded; the powder made into cakes, somewhat in the fashion of our chocolate; Table 2. Alphabetical list of names in Parkia dealt with in this paper, showing their synonymy according to Hopkins (1983 they form an excellent sauce for all kinds of food. The farinaceous matter surrounding the seeds is made into a pleasant drink, and they also make it into a sweetmeat."

Materials and Methods
Names referring to Parkia in Africa and Madagascar are listed in date order within the four species concepts of Hopkins (1983), with invalid and illegitimate names discussed briefly. The varieties established by Hagos and de Wit (Hagos 1962) and Chiovenda (1932) are treated under their basionyms. Two names from Madagascar that were originally published in Parkia but which refer to species of Xylia Benth. are not discussed. Barcodes for herbarium sheets and material in carpological boxes or in spirit are given where known and material seen, either in the herbarium or as an online image, is indicated "!"; "n.v." is indicated only where necessary to avoid confusion. The abbreviations "lv.", "fl." and "fr." indicate leaves, flowers and fruits respectively. Images of many types were viewed through Jstor Global Plants (online). Other online databases, many with images, were also consulted, including those for collections at B, BM, BR, E, G, K, L, MO, P, US, W and WAG . Most of the websites for these herbaria were located using Index Herbariorum (Thiers, continuously updated). This was originally a manuscript name given to a small number of specimens at BR by the French botanist J. P. Louis Pierre (De Wildeman 1907). It commemorates Klaine, a missionary in Gabon, on whose specimens Pierre worked (Breteler 2005) although the material cited by De Wildeman (1907: 129;1910: 190) under this name was not collected by Klaine. Parkia klainei, or its orthographic variant P. klainii, has appeared in several publications but the name has never been validly and legitimately published. For instance, De Wildeman (1907Wildeman ( , 1910 listed it twice as a nomen nudum and although Chevalier (1916: 193) and Pellegrin (1924: 111) mentioned characters of the wood and flower colour respectively, this is insufficient to constitute a description or diagnosis. Heitz (1943) provided a description in French but it was published after the requirement date for a description in Latin and furthermore, he cited the names P. bicolor and P. zenkeri as synonyms, which would have made the name illegitimate, even if his description had been in Latin.

Names and Types
This name does not appear in IPNI (online) although it is listed in GBIF (online) where images of two sheets of Laurent 1828 from LY are shown, bearing determination labels of E. De Wildeman (LY0227144, three fruits; LY0227145, three leaves). Harms (1911: 34 Hagos (1962) and Hopkins (1983) also reported type material at G and GOET that is not currently on Jstor Global Plants nor in other databases).

Residual syntypes:
No material is known to be extant for either Büsgen 432 or Krücke 13.
Harms was based at B and the top set of material collected by George Zenker was also at B (Jstor Global Plants online; TL-2 online). However, all the type material of Parkia zenkeri at B, including collections by Büsgen and Krücke, appears to have been destroyed. Baker (1930) put the name Parkia zenkeri into the synonymy of P. bicolor and this has been followed by most subsequent authors, including Hagos (1962), who placed all the material he studied from Lower Guinea and the Congo in P. bicolor var. bicolor, including Zenker 3498. Major flora treatments for Gabon and the Congo (Gilbert & Boutique 1952;Villiers 1989) and Angola (Exell & Mendonça 1956) also placed P. zenkeri in the synonymy of P. bicolor, as did de la Estrella et al. (2010) for Equatorial Guinea. Mimosoid legumes have not yet been treated for the Flora of Cameroon.

Parkia biglobosa (Jacq.) R.Br. ex G.Don
A number of synonyms of Parkia biglobosa from publications that predate Brown (1826) and that have rarely been taken up in the literature or the herbarium are not discussed here. For several, no obvious type is known or the name is based on the type of P. biglobosa. These names are listed in IPNI (online) under P. biglobosa and most are also discussed in Hopkins (1983). Lectotype (designated in Hagos [1962: 254]): Jacquin (1763), tab. 179, fig. 87, based on a specimen from Martinique. Many Jacquin collections are at BM but no herbarium specimen referable to his Mimosa biglobosa appears to be extant there. The original material is more than likely to have included leaves and capitula collected in the field plus preliminary drawings, as well as the published illustration in Jacquin (1763). Since the illustration is the only element from amongst these that is known to be still in existence, it is cited here as a lectotype, rather than a holotype. Hagos (1962: 254) appears to have been the first to cite this drawing as the "type", and so the lectotypification is attributed to him. Brown (1826) described Parkia africana at the same time as he published the generic name Parkia. Under P. africana, he cited several synonyms including Inga biglobosa. This is an indirect reference to Jacquin's Mimosa biglobosa (Jacquin 1763) through the combination Inga biglobosa (Jacq.) Willd. (Willdenow 1806(Willdenow : 1025 and thus P. africana is a superfluous name, and as such, it is illegitimate and its type is that of Mimosa biglobosa (contra Hopkins 1983).

Parkia africana
The material available to Brown that he used in part for his description of Parkia africana was collected by Hugh Clapperton (Clapperton s.n., s.dat., BM! BM000842200 [leaf only], BM000842199 [fruit, seeds, peduncle and clinanthium i.e. the swollen receptacle at the end of the peduncle on which the flowers are borne], both parts mounted on the same sheet). Three labels on this sheet were written by Brown, with the locality of Bornu added in a different hand. Brown's description of leaf characters for P. africana does not entirely agree with the leaf of Clapperton s.n. (see Keay [1955] and Hagos [1962] for discussion).
Most of the plant specimens from Denham, Oudney and Clapperton's expedition to western Africa were collected by Oudney, who died during the expedition, and only a few were made by Clapperton (Brown 1826). Their plant material was presented to Brown who wrote the botanical appendix for the account of their "Travels", and the specimens were incorporated into BM from Brown's personal herbarium in the late 1800s, following his death (J. Wajer, pers. comm. 2022). Keay (1955) gave reasons for considering the name Parkia africana illegitimate and he published P. clappertoniana Keay to replace it. Hagos (1962) (Hopkins 1983: 145). The plant illustrated by Palisot de Beauvois does not closely resemble P. biglobosa and although the leaves and the height of the tree ("moyenne élévation") could suggest this species, the habitat ("sur le bord des rivières") and depictions of the capitula and flowers do not. The flowers of the apical part of the capitulum are shown with far exserted stamens, which is incorrect for any species of Parkia in Africa. Palisot de Beauvoir's material of this genus at G belongs to P. bicolor (Hopkins 1983 Macbride (1919) provided a nomen novum for Parkia intermedia Oliv. because that name was already occupied by P. intermedia Hassk. (Hasskarl 1843) and he made no comment about the type. Exell (1944) stated that the type of P. oliveri was Mann 1099 at K, but because two sheets of this gathering are at K, a second-step lectotypification is made here and the lectotype is the sheet with annotated drawings. An additional sheet at K with a label only indicates that further material is in the spirit collection but no record for this was found in the catalogue in April 2022. Exell (1944) also mentioned two collections by Welwitsch, 1788 (BM, K, LISU) and coll. carp. 503 (BM); the latter is a probably a residual syntype since Oliver would have had access to any material now at BM. It is not clear whether the carp. collection is from the same gathering as Welwitsch 1788 or a different one.

Parkia filicoidea
Welw. ex Oliv. var. glauca Baker f. (1930: 781).  Baker (1930) cited a single collection as the type and the material at BM is in two parts, an herbarium sheet and fruits in the carp. collection; the name is lectotypified here on the herbarium sheet. Keay (1955: 209 Although Keay (1955) designated material at K as the holotype, two sheets of Onochie FHI 34652 are at K: K000232180 has a holotype label and is marked "sheet 1" and K000232181 lacks a type label and is marked "sheet 2"; both sheets have leaves, flowers and fruits. However, Keay stated in the protologue that flowers and leaves were collected on 11 Dec. 1954 and fruits on 26 Feb. 1955, and so this material constitutes two separate gatherings. The flowering and leaf material on one sheet at K is designated here as the lectotype, with flowers and leaves elsewhere as isolectotypes, and the fruits at K and elsewhere, often mounted on the same sheets as the flowers and leaves, become residual syntypes. In addition to the herbarium material, flowers in spirit are preserved at K and also reported at B, BM and BR. Because the type was collected in the FHI number sequence, further type material presumably exists at that institution but this has not been verified.  Keay (1955) later referred it to P. clappertoniana. This is the only specimen mentioned in Oliver's protologue that definitely has fruit and so the part of his description that refers to the pod ("scarcely subterete") must be excluded from the concept of P. filicoidea. Brenan (1959) cited Welwitsch 1787 from LISU as the lectotype of Parkia filicoidea and but as three sheets from this herbarium are shown in Jstor Global Plants (online), a second-step lectotypification is made here. The lectotype material (LISU208886) has previously been labelled as the holotype and it consists of capitula sliced longitudinally, with their peduncles and compound inflorescence axes, plus a packet containing loose flowers, with a handwritten description attached; the other two sheets at LISU consist of leaves only. However, a Welwitsch collection number can refer to material from several different individuals that he considered all to belong to a single species, rather than referring to a single gathering (Albuquerque et al. 2009). All the material seen that is labelled Welwitsch 1787 consists of either capitula and associated parts (peduncles, clinanthia, loose flowers) (LISU208886, BM000842195), or leaves (LISU20888, LISU208887, BM000842196), or both on the same sheet (COI00006033, G00022501, K000232174, P00418346). According to the longer hand-written descriptions attached to the flowering sheets at LISU and BM, leaves were collected in January and flowers in April, indicating separate gatherings, though not necessarily from different trees. The shorter description on both sheets mentions February and April, without specifying either leaves or flowers; the label for "Welw. Iter Angolense" on LISU208886 is unclear ("fl. Feb. [obscured] Apr. 1857"). Hiern (1896) amalgamated this information and stated "In foliage Jan., fl. Feb. and April".

Parkia filicoidea
Material collected on different dates, even if from the same tree, constitutes different gatherings and so the flowers and leaves of Welwitsch 1787 form at least two separate collections. According to the original hand-written labels, the timing for the collection of flowering material is ambiguous and it is not clear whether flowers were collected twice, or only once and references to flowers in both February and April are due to errors in copying label data. However, if more than one flowering collection was made, we have no means of identifying which flower-heads were collected when. I therefore propose that all the flowering material should be treated as part of the lectotype unless and until someone is able to determine conclusively whether more than one gathering is involved. All the leaf material of Welwitsch 1787 is cited among the residual syntypes. Even if the leaves were to be designated as the lectotype, we have no guarantee that they were all collected on the same date in January nor from the same tree.
Besides Welwitsch 1787, other Welwitsch material of Parkia filicoidea exists. At K, the herbarium catalogue states that "Old fruits of this number [presumably 1787] said to be in the Welwitsch Collection (carp. coll. [504])". Although no material corresponding to this was found in the carp. collection at K nor in the catalogue of Kew's Economic Botany collections in April 2022, a box in the carpological collection at BM (BM001100691) is labelled "Welwitsch 504, Maio 1857" and contains bits of broken pod and a seed embedded in pulp; the label states that the pods are eaten by monkeys. Reference to this collection in Hiern's catalogue of Welwitsch's African plants (Hiern 1896, p. 305, "Old fr. end of May 1857") indicated a later collection date than for Welwitsch 1787.
According to Figueiredo & Smith (2020), some names for which the authorship is usually given as Welw. ex [...] should be ascribed to Welwitsch alone if the author who published the name used Welwitsch's description. Descriptions by Welwitsch, identical except for the handwriting, are attached to sheets LISU208886 and BM000842195 but Oliver's description in the Flora of Tropical Africa (1871) is not identical to them. The name "Parkia filicoidea Welw." is given on specimen labels and listed in the index to Oliver's account, but authorship of the name must remain Welw. ex Oliv. Harms (1899: 261). Parkia filicoidea var. hildebrandtii (Harms) Chiov. (Chiovenda 1932: 180). Types as for P. hildebrandtii. Type as cited in protologue: "Sansibar-Küste: Mombassa (Hildebrandt n. 1975 Because the sheet of Hildebrandt 1975 at B appears to have been destroyed, the K sheet is designated here as the lectotype. A sketch at BM (BM013719105) showing part of a pinna plus part of a pod is labelled "Herb. Berol. 1926" and was probably made by E. G. Baker in preparation for the Leguminosae of Tropical Africa (Baker 1930) (J. Wajer, pers. comm. 2022; it may be the only evidence remaining of the material once at B.

Parkia hildebrandtii
Harms (1899) distinguished Parkia hildebrandtii by its large, very broad leaflets and stated that the pods were 2 -2.5 cm broad and scarcely constricted between the seeds. Baker (1930) placed this name in the synonymy of P. filicoidea and no major revisions or flora treatments, including that by Brenan (1959) for East Africa, have subsequently recognised P. hildebrandtii as distinct at species level. When Chiovenda (1932) published the comb. et stat. nov. P. filicoidea var. hildebrandtii he cited Senni 105 (herbarium not indicated, possibly FI or FT) as a representative collection from Somalia but Thulin (1993) did not maintain this taxon and recorded simply "P. filicoidea" for Somalia, based on Hemming SRS 568/1 (K!), with P. hildebrandtii and P. filicoidea var. hildebrandtii given in synonymy. Hagos (1962) maintained Chiovenda's variety but cited only two collections, one from Congo (Herman 2112, BR! BR0000018850826) and the other from Tanzania (Peter s.n., B), and he placed all remaining material from east and central Africa in P. filicoidea var. filicoidea. In his key, he distinguished var. filicoidea, which had "pods cylindrical or nearly so, depressed between seeds" from var. hildebrandtii with "pods laterally compressed, not or scarcely depressed between seeds" (Hagos 1962: 236). Harms (1902: 154 1901 (1900 -1901), Busse 896 (EA!, G! G00022502).

Parkia bussei
No material of either of the syntypes of Parkia bussei, Goetze 1487 and Busse 896, appears to be extant at B. Both collections are from what is now southern Tanzania. According to Brenan (1959), Busse 896 came from the Njombe/Songea Districts in Ruhuhu Region, not far from where Goetze 1487 was collected, near the northern end of Lake Malawi, in Rungwe District at the southern tip of Mbeya Region. Another sketch at BM, probably made by E. G. Baker (see above), shows a pinna and a pod from Busse 896 and is labelled "Herb. Berol. 1926", presumably based on the material that is no longer extant at B. Harms (1902) considered that Parkia bussei did not differ in its foliage from P. hildebrandtii but stated that its pods, at 3.5 cm, were broad. Baker (1930) put P. bussei in the synonymy of P. filicoidea and the treatment for the Congo (Gilbert & Boutique 1952) is the only major flora to maintain P. bussei as distinct, all the others placing this name in the synonymy of P. filicoidea, including the treatment by Brenan (1959). Gilbert & Boutique (1952: 141, key) distinguished between the two as follows: P. bussei: pods narrowly oblong, flattened, 2.5 -3.5 cm wide; Upper Katanga; P. filicoidea: pods linear-subcylindrical, 1.3 -1.9 cm wide, constricted between the seeds.  Villiers (2002) cited Perrier de la Bathie 3098 as the lectotype of this name but because three sheets of this number exist at P, a second-step lectotypification is made here. A sheet of this number is also listed at MO with no image. A sheet at US (US00001036) was collected by Perrier de la Bathie but lacks both a collection number and precise locality so it is not possible to say whether it is an isolectotype or a residual syntype. expedition and Welwitsch's collections from Angola; Ian Turner for advice on lectotypification; Laura Pearce for technical assistance; Jacek Wajer for his help at BM and with the name Parkia africana; and finally I am grateful to two reviewers for numerous helpful suggestions and corrections.

Conflict of interests
The author has no conflict of interests regarding this paper.
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