Isoetes delalandei J. Lloyd, 1851

Boudrie, Michel, Rouhan, Germinal, Malécot, Valéry & Troia, Angelo, 2024, On the typification of three Isoetes names (Isoetaceae, Lycopodiopsida) described from France, Phytotaxa 641 (4), pp. 286-294 : 287-288

Isoetes delalandei J. Lloyd , Notes Fl. Ouest France: 25−26. 1851.

Lectotype (designated here):— [ FRANCE: Morbihan ] île de Houat, mai 1850, Abbé J.- M. Delalande s.n. ANG, accession number MBAng.2023.0.12369! (in Fig. 1 , the plants on the left top of the sheet, on a black paper background); isolectotypes: ANG, accession number MBAng.2023.0.12370! (in Fig. 1 , the fragments on the lower half of the sheet, on a black paper and on a white paper background); NTM, accession number MHNN. B.10092.6! ( Fig. 2 ).

Extract from the protologue ( Lloyd 1851: 26).—“ Cette plante curieuse est voisine de l’I. histrix Durieu , et je me propose de l’étudier sur le frais, afin d’en donner une description plus complète. Elle a été trouvée par M. l’abbé Delalande en mai 1850, formant un gazon fin dans les intervalles ras d’une lande sèche, granitique de l’île de Houat, dans le Morbihan ” [English translation: This curious plant is close to I. histrix Durieu , and I propose to study it on living material, in order to give a more complete description. It was found by Father Delalande in May 1850, forming a fine turf in the gaps within a dry, granite moor of the island of Houat, in Morbihan].

Extract from the second description ( Lloyd 1852: 27).—“ Au mois de mai 1850, M. l’abbé Delalande avait rapporté de l’île de Houat quatre individus de cette espèce intéressante, mêlés au Romulea Columnae. Deux de ces échantillons reçus pour être déterminés m’ont servi à rédiger une description nécessairement incomplète… ” [English translation: In May 1850, Father Delalande had brought back from the island of Houat four individuals of this interesting species, mixed with Romulea columnae. Two of these samples received for identification were used to write a necessarily incomplete description…].

Note.— Isoetes populations belonging to the I. histrix group are still present on Houat Island (Hermann Guitton pers. comm. 2022). It will be useful to compare them with the type specimen of I. delalandei and to establish whether I. delalandei is really a distinct taxon compared to I. histrix and to other taxa of this group.

Figures

FIGURE 1. Lectotype of Isoetes delalandei (ANG, accession number MBAng.2023.0.12369, plants on the left top of the sheet, on a black paper background); the other plants on the sheet are labelled as a separate specimen (accession number MBAng.2023.0.12370) and are isolectotypes.

FIGURE 2. Isolectotype of Isoetes delalandei in NTM (accession number MHNN.B.10092.6).