Observations on a proposal to conserve the name Euphorbia obtusifolia Poiret.

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Bot. Macaronésica 24: 143-147 (2003) 143
OBSERVATIONS ON A PROPOSAL TO CONSERVE THE NAME
EUPHORBIA OBTUSIFOLIA POIRET.
DAVID BRAMWELL
Jardín Botánico Canario «Viera y Clavijo», Apdo. 14 de Tafira Alta. 35017 Las Palmas de Gran Cana-
ria, islas Canarias, España.
Recibido: noviembre 2000.
Key words: Euphorbia obtusifolia, Canary Islands.
Palabras clave: : Euphorbia obtusifolia, islas Canarias.
The Proposal 1349 by MOLERO & ROVIRA (Taxon 47: 469) would appear to be
unnecessary and based on a rather optimistic interpretation of the type specimen
of Euphorbia obtusifolia Poiret. It, therefore, only adds to the confusion surrounding
the name E. obtusifolia.
The name Euphorbia obtusifolia Poiret was published by Poiret (POIRET IN LA-
MARCK, 1812) who recognized that Euphorbia mauritanica sensu Lamarck was a
new species distinct from the E. mauritanica of Linnaeus. In Lamarck´s description
of E. mauritanica sensu Lam. non L. (Encycl. 2 : p. 418, 1788 (not p. 43 as given
by MOLERO & ROVINA,1998a)) he stated “cette plante crôit dans les lieux maritimes
de l’Afrique”. IT WAS OBVIOUSLY NOT INTENDED TO REFER TO A PLANT FROM THE
WESTERN CANARY ISLANDS.
Unfortunately, Poiret overlooked an earlier use of the epithet obtusifolia by La-
marck for a Euphorbia species from the Iberian Peninsula, probably E. terracina
but possibly E. medicaginea as noted by Molero & Rovira.
Desfontaines, also realizing that Lamarck’s E. mauritanica was not the same as
that of Linnaeus, had previously (1804) published the name E. virgata Desf. as a
substitute for it but it seems that the E. virgata of Waldstein & Kitaibel just predates
Desfontaines’ use of the name and has priority. Chrtek & Skocdopolova (Acta Mus.
Nat. Prag. XXXVIIB: 224, 1982) give 1803 as the date of publication of the Walds-
tein & Kitaibel name. Desfontaines, like Lamarck, intended his name to refer to the
African species and gives its origin as “Afr.”, while in the same work the Canary
Islands species are cited as “Canaries” or “des Canaries”. Sweet, in 1818, publi-
shed the name Euphorbia lamarckii intending it to replace both E. mauritanica sen-
su Lam. and E. virgata Desf. and also stated its origin as being from “Africa”.
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DAVID BRAMWELL
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Sweet also used the terms “Canaries” and “Teneriffe” to refer to Canary Islands
plants. It is, therefore, clear that none of these authors intended their names to be
used for the Canarian species, and especially not for the one confined to the west-
ern islands.
The arguments presented by the authors of Proposal 1349 for a Tenerife origin
for the type specimen they selected are, to say the least, optimistic in their interpre-
tation. The specimen is in very poor condition. Most older herbarium sheets of the
Canarian Euphorbias tend to be so. They are extremely fragile and the inflorescen-
ces tend to break up quickly so that their original structure is difficult to decide es-
pecially if fragments have been lost over the years. Young inflorescences are often
unbranched until after the first bud opens and, in any case, both the western Ca-
narian taxon and the N. African/eastern Canaries taxon are extremely variable in
this character. The illustration of a N. African specimen in Vindt’s monograph
(1953) actually shows a plant without secondary rays. If the type specimen repre-
sents a young inflorescence, and there appears to be no sign of capsule formation
which suggests that this might be the case, then bract measurements may also be
misleading as they may be taken from immature ie. not fully developed bracts. The
development of secondary rays often depends on climatic conditions and they
usually abort early in periods of drought (as was the case in the years 1998 and
2000). The fact, therefore, that the old, poorly preserved type specimen does not
have secondary rays cannot be used as a good reason for attributing its origin to
Tenerife, there are grounds for considerable and reasonable doubt.
The cyathial gland shape is also used by Molero & Rovira to justify a Tenerife
origin for the E. obtusifolia lectotype. Round, truncate, hornless glands are, indeed,
very typical of the western Canaries taxon but they are by no means exclusive to it.
On Gran Canaria it is by not unusual to find individual plants and even populations
of the African/eastern Canarian taxon with hornless glands. I have in front of me a
living specimen from a plant originally collected personally in Morocco between
Cap Ghir and Agadir in 1991 which has central cyathia with entire, hornless glands
and the outer rays with typical horned glands and, further, there is no sign of sec-
ondary branching of any of the 8 pleiochasial rays. Molero & Rovira themselves
(1998a), in their comment on E. pseudodendroides H. Lindb., a taxon originally
described from Morocco now considered to be part of the N. African/eastern
Canaries complex, state that it has “a tendency of the cyathium glands to be
truncate or present shorter horns”. VINDT (1953) also described the cyathial glands
as being “raremente plurilobulées”.
In his comments on pseudodendroides he refers to the “glandes à cornes plus
cortes” and to the less branched inflorescence but notes that “ces caractères son
très variables chez l’ espèce”. This character is also not a definitive one for assig-
ning geographical origin for the Lamarck specimen chosen as the lectotype of
E. obtusifolia and cannot be used to support “the unquestionable origin of the type
material” (MOLERO & ROVINA, 1998a: 323). The specimen could be from either the
western or the eastern Canaries or from North Africa. It could equally be a speci-
men of the Madeiran E. piscatoria Aiton which is inexplicably not included in the
revision of the Macaronesian taxa (MOLERO & ROVINA, 1998a). This species which
has both entire and horned glands, simple and compound inflorescences and small
bracts (3-6.5 mm) can also display all the characters claimed by the authors of the

OBSERVATIONS ON A PROPOSAL TO CONSERVE THE NAME EUPHORBIA OBTUSIFOLIA 145
proposal as proof of the Tenerife origin of the lectotype of E. obtusifolia. It was in
cultivation in European botanical gardens early in the 19th Century having been
introduced by Masson in 1777. In view of the poor state of the specimen and the
overlap in characters between several species I consider it virtually impossible to
ascribe it with exactitude to any one of the candidate taxa.
Despite Molero & Rovira´s claim (1998b) that the name E. obtusifolia has been
used “for many years to designate a species of ‘tabaiba’that is one of the most
widespread and characteristic plants of the coastal landscape of the western Ca-
nary Islands” an examination of the references they cite shows that this is not so.
In general the literature on the Canarian flora adds to the confusion about the
name E. obtusifolia and it has been used indiscriminately for the two Canarian taxa
and the North African populations as well. Most authors have followed Webb (1847
) in ascribing it to all the Canary Islands and mixing its distribution with that of
E. regis-jubae Webb & Berth., the eastern Canarian and African taxon. KNOCHE
(1923) confused the two species, citing E. regis-jubae from Tenerife and the Wes-
tern Islands and E. obtusifolia from Tenerife and Gran Canaria. LINDINGER (1926)
correctly ignored the name E. obtusifolia and used the epithet broussonetii
(E. dendroides L. var. broussonetii (Willd.) O.Kuntze) for the plant from the West-
ern Canaries and E. regis-jubae for the Eastern islands and Gran Canaria, though
he also erroneously included Tenerife in its distribution. Santos (1983) reported it
from La Palma as subspecies regis-jubae which he goes on to list as being from all
the Canary Islands. PITARD & PROUST (1908) gave it as being “dans toutes les iles”
and specifically cited two Gran Canaria (i.e. E. regis-jubae) localities. KUNKEL
(1977) got it totally the wrong way round giving Lanzarote; Fuerteventura and Gran
Canaria as its geographical home and included all records of E. regis-jubae from
these islands in E. obtusifolia. Hansen & Sunding (1993) continue to cite E. obtusi-
folia from all the Canary Islands but give the distribution of E. regis-jubae as Tene-
rife, la Gomera and la Palma, all in the western Canaries, again confusing the dis-
tribution of both taxa. In fact, only LID (1967) cites E. obtusifolia as the western
Canaries taxon and E. regis-jubae as being from the eastern islands.
A pre 1994 International Code of Botanical Nomenclature solution to the pro-
blem was provided by BRAMWELL & BRAMWELL (1990) who, considering
E. obtusifolia Poiret to be an illegitimate later homonym of E. obtusifolia Lam. ex-
cluded it from the Canarian flora and, at the same time, cleared up the confusion
about the distribution of the two Canarian taxa ascribing the name E. broussonetii
Willd. ex Link to the western Canarian species and E. regis-jubae Webb & Berth.
To the N. African/ Eastern Canarian species. Even under the 1994 Code and if the
above expressed doubts about the geographical origin of the type are accepted,
this solution would remain the correct and valid one as it would also remove E.
lamarckii Sweet, based on the same type as E. obtusifolia Poiret from the discus-
sion. This solution requires no name conservation and no acceptance of a dubious
type specimen of an illegitimate and very confused name which was never in-
tended by its author to be used for a Canarian plant. CARTER & EGGLI (1997) in the
important Cites Checklist of Succulent Euphorbia Taxa also adopt this solution
listing E. regis-jubae and E. broussonetii as the names for the two Canarian taxa
and the introduction to the Checklist states «Following the approval by the Nomen-
clature Committee the 10th Meeting of the Conference of the Parties has adopted

DAVID BRAMWELL
146
the «CITES Checklist of Succulent Euphorbia Taxa (Euphorbiaceae) as standard
reference to the names of species of succulent Euphorbias».
There is no doubt that Lamarck, Poiret, Desfontaines and Sweet all intended
their names to be used for the taxon from N. Africa, none of them even mention the
Canaries in their protologues. This coupled with the uncertainty of the interpretation
of the lectotype, the fact that Poiret’s name is an illegitimate homonym under the
Code and that a perfectly legitimate solution is already in place in the current
widely distributed, standard Flora of the Canary Islands and in the official CITES
Checklist means that little is served by Proposal 1349.
The Committee should ask why do we want to conserve an illegitimate name
with an uninterpretable type specimen, a name which was never intended to be
used for the species to which the authors of the Proposal wish to apply it and which
has been a constant source of confusion in the literature for almost all of the past
200 years?
NOTE: A prepublication version of this article was circulated to the Committee
for Spermatophyta who resolved the issue in favor of the rejection of Proposal
1349 and the name E. obtusifolia Poiret on the grounds outlined here by 14 votes
to 1 (TAXON 49: 800-801, 2000). The current correct names for the Canarian spe-
cies are, therefore, E. broussonetii Willd. ex Link for the species from Tenerife and
the western islands and E. regis-jubae Webb & Berth. for the species from Gran
Canaria, Lanzarote and Fuerteventura.
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