Lamarck’s new species of Mesembryanthemaceae and the types of their names

The holotype of Mesembryanthemum echinatum Lam. is an unpublished, sketchy drawing kept in the Lamarck herbarium (P-LAM). The holotype of the name M. vaginatum Lam., which has not been taken up again since its original publication, is also in P-LAM. That name has priority over M. ciliatum Aiton, pertaining to a species currently placed in Brownanthus. Two new combinations are proposed: Brownanthus vaginatus (Lam.) Chesselet & M.Pignal and Brownanthus vaginatus subsp. schenckii (Schinz) Chesselet & M.Pignal.


INTRODUCTION
The French naturalist Jean Baptiste de Monnet de Lamarck (1744Lamarck ( -1829) ) established the first evolutionary synthesis of modem biology and participated in the great debates about living species and evolution of life that took place in late 18th century Europe (Corsi 2001).Lamarck's interests covered diverse topics including botany, chemistry, meteorology, and notably zoology, where he made the fundamental distinction between ver tebrates and invertebrates, his contribution to botany is voluminous.In the Flore frangoise (1779), Lamarck used the principle of dichotomous sorting for the identi fication of all taxa, thereby enabling identification to species level, a technique now widely used by botanists.In the Encyclopedie methodique. he described numerous new species, but in the Mesembryanthemaceae only two.These are the topic of this contribution.
The Encyclopedie methodique, published between 1783 and 1808, comprises eight volumes plus supple ments.The two first volumes, and the third up to the letter P, are entirely the work of Lamarck.Many of the plants described there correspond to specimens kept in the Lamarck Herbarium (P-LAM).This valuable historic collection is rich in types and comprises ± 19 000 speci mens.An Internet site dedicated to the works and contri butions of Lamarck (www.lamarck.net)provides digi tized images of the first 7 (XX) specimens, and the others too, are being made progressively available there and through the SONNERAT database (http://www.mnhn.fr/base/sonnerat.html).The Lamarck herbarium changed hands several times: it was sold, towards the end of Lamarck's life, to the German Botanist Johannes Roeper (the first to use floral diagrams), then bought by the University of Rostock in Germany and finally acquired, in 1886, by the Museum of Paris.The collection is now housed not far from its origin in the house of Buffon where Lamarck had his office at the Jardin des Plantes (Aymonin 1980(Aymonin , 1981)).
Lamarck, in the section on Ficoide.described two new mesemb species in the Encyclopedie (1788: 478): Mesembryanthemum echinatum Lam., a distinctive species, and the oldest name in the genus Delosperma N.E.Br., and Mesembryanthemum vaginatum Lam. the first validly published name that applies to a species cur rently in the genus Brownanthus Schwantes.

Mesembryanthemum echinatum Lam.
In the case of M. echinatum, a mix-up due to the re assembly of the Lamarck collection has engendered con fusion.In addition to being moved several times, the Lamarck herbarium was included into and later separat ed from the general herbarium at Rostock (the latter process taking no less than five years: see Aymonin 1981).Lamarck did not wish specimens to be glued as he pre ferred to observe the plants from all angles.His original herbarium consisted of unmounted specimens of dried plants with loose labels in species covers.They were mounted subsequently w hen Edmond Bonnet, curator of the herbarium at the Museum, was given the task of re arranging the Lamarck collection in 1900.Bonnet first had the specimens attached with paper strips and, for its arrangement, adopted the order of Durant (that largely follows the system of Bentham and Hooker).Lamarck preferred an arrangement that reflected natural relation ships to an alphabetical system such as that of Linnaeus.The consequences of keeping the plants unmounted would not have been too serious had the herbarium been kept in Paris, such as those of the Jussieu (P-JU), acquired by the Museum in 1857 after the death of Adrien de Jussieu, and that of Michel Adanson (1727Adanson ( -1806)).donat ed to the Paris herbarium in 1924.Fixing of specimens of the Jussieu herbarium with pins and strips is thought to have taken place in the mid-19th century but the fixing of specimens with sticky strips took place much later in the history of this herbarium.
The name Mesembryanthemum echinatum was pub lished by Lamarck (1788) where the species was de scribed and qualified as v.v.(vu vivant, or vidi vivum).to indicate that the description was based on live material grown at the Jardin des Plantes.The species, currently in Delosperma N.E.Br., has been the subject of past debate (Taylor & Eggli 1986).The combination in Delosperma was made by Schwantes (1927) who gave the basionym as 'M.echinatum Ait.' (Aiton 1789).However, Lamarck's name was published one year earlier in 1788 [not 1786 as stated by Taylor & Eggli (1986), see Stafleu & Cowan (1979)].In his book on succulent plants, Candolle (1799) suggested that the material from which Lamarck's description was made, originated from the Cape of Good Hope and was brought to Britain by Francis Masson in 1774, from where it came to the Jardin des Plantes.It is possible that Aiton's concept of M. echinatum was based on material of the same origin as Lamarck's plant, although this cannot be shown unequivocally.
What was still a debatable issue in 1986 has since been clarified by a new provision in the ICBN (Greuter et al. 2000, Art. 33.6(a)): even though Schwantes, in publishing the combination Delosperma echinatum, refer-<1 5r*£inu* ./. red to the wrong basionym author, Aiton; and even though Aiton did not mention Lamarck's earlier valida tion of Mesembryanthemum echinatum, of which he may have been unaware; still Lamarck is to be considered as the basionym author, and the correct author citation for the combination in Delosperma is D. echinatum (Lam.)Schwantes.
As no original specimens of M. echinatum are extant, Taylor & Eggli (1986) designated a photograph of Schwantes (1927) as neotype, and this neotypification was accepted by Hartmann (2001a).However, an origi nal element is extant in the Lamarck herbarium, an illus tration which (in the absence of a preserved specimen of the living plant) must be accepted as the holotype.Therefore, the designated neotype has no standing.
Although Taylor & Eggli (1986) consulted a micro fiche of the herbarium sheet represented in Figure 1, they failed to realize the true significance of the relevant slip of paper (Figure 2).What Taylor & Eggli (1986) inter preted as a misidentification is in fact the result of the complex history of Lamarck's herbarium.When the col lection was finally pasted to herbarium sheets, a small piece of paper with the description and sketch of M. echi natum, by Lamarck, became associated with the wrong herbarium specimen, of Lampranthus scaber (L.) N.E.Br.(= Mesembryanthemum scabrum L.) (Figure 1).It is pos sible that the word scabra in the description of M. echi natum prompted the association of the note with that specimen.
Lamarck's slip obviously dates back to the time when the protologue was written.Along with the description, it includes a sketch of the plant itself, which is original material for the name as defined in the ICBN (Art.9 Note 2).Although very simple, this illustration agrees with D. echinatum as currently understood, a highly dis tinctive mesemb with echinate leaves and sessile flow ers, unique and atypical in the genus as pointed out by Koutnik & O'Connor-Fenton (1985).As no other origi nal material is known to exist, we consider Lamarck's original sketch of M. echinatum as the holotype of the name (Figure 2).The associated description begins with the phrase-name provided by Lamarck in the protologue.It reads: 4Mesembryanthemum echinatum.M esem bryanthemum foliis obovatis tereti-triquetris verruculosis echinato-hispidis, floribus sessilibus\ The type illus tration, in the Lamarck herbarium in Paris (P-LAM), is attached to the specimen of M. scabrum bar-coded as P00307737.

Mesembryanthemum vaginatum Lam.
The second new mesemb species described by Lamarck (1788) is Mesembryanthemum vaginatum, with the accompanying phrase-name: 4Mesembryanthemum foliis oppositis basi connato-vaginantibus, vaginis persistentibus crebris infeme barbatis, floribus corymbos is \ This validating diagnosis is followed by the indica tion '(v.s.)' [vu sec, or vidi siccum], meaning that herbar ium material was available for study.The corresponding specimen in P-LAM (Figure 3) was brought to Paris from the Cape of Good Hope by Pierre Sonnerat, the French naturalist and draughtsman who visited the Cape in the late 18th century, but is known for his work on the Seychelles, India, the East Indies and China (Gunn & Codd 1981).His specimens were mainly presented to Jussieu and Lamarck, in Paris.
The specimen held in the Lamarck herbarium (P-LAM, bar code P00307735) is considered to be the holotype of M. vaginatum Lam.The re-discovery of this type specimen has nomenclatural implications.In modem lit erature the species represented by that type is known as  Lamarck's name is not accounted for elsewhere in De Candolle's work, and is now utterly forgotten.We have considered the option of submitting a proposal to con serve the name M. ciliatum Aiton against it, in the inter est of stability of botanical nomenclature.We are, how ever, discarding that option and proposing a name change for nomenclatural reasons.Although the contin ued use of the name Brownanthus ciliatus (Aiton) Schwantes may be preferred for practical reasons, it is not proposed here as the species is little known, unim portant in horticultural trade, only occurs in Northern and Western Cape, and the name is scantly used in the lit erature.The application of the rule of priority requires the following nomenclatural changes: