Jodina rhombifolia subsp. delasotae Arana & Luna, 2019

Arana, Marcelo D. & Luna, María Luján, 2019, A new subspecies of Jodina rhombifolia (Santalales: Cervantesiaceae), with taxonomical considerations, Phytotaxa 425 (4), pp. 208-218 : 213-215

Jodina rhombifolia subsp. delasotae Arana & Luna , subspecies nova

Type:― ARGENTINA. Provincia de Buenos Aires: Partido de Magdalena, “talares” (35º 11’ S, 57º 19’ W), 30 June 2010, L. Luna 123 (holotype RCVC, isotypes LP, SI).

Ilex cuneifolia L. var. bonariensis de Candolle (1825: 16) , based on Ilex cuneifolia L. var. β (bonariensis?) Lamarck (1789:148). Jodina bonariensis (DC.) Kuntze (1898: 283) . Type:― ARGENTINA. Buenos Aires province (“ Buenos Ayres ”), 1767, P. Commerson s.n. (lectotype P 00678750!, designated here) ( Fig. 4 ).

Jodina cuneifolia (L.) Miers (1878: 84).

Diagnosis —Differs from Jodina rhombifolia subsp. rhombifolia , besides the distributional range, by the dorsiventral mesophyll, the stomata present only on the abaxial epidermis and 4- and 5-merous flowers in proportion 50–50, even in the same inflorescence; glandular disk with large and erect, obtuse, rounded lobes dark green. Also, the leaves are usually dark green with prominent venation.

Small trees up to 8 m high, with alternate, rhombic, glabrous, stiff, usually very dark green leaves, with one spine on each side and one at the apex; base of leaf cuneate, petiole very short (essentially lacking), epidermis multilayered, dorsiventral mesophyll and stomata present only on the abaxial surface. Inflorescence one or several, small, pedunculate, axillary strongly compact clusters of 5 or 10 flowers, with pubescent bracts. Flowers bisexual and monochlamydeous, tetramerous and pentamerous 50– 50 in proportion; Petals abaxially densely pubescent, adaxially glabrous except for a large post-staminal tuft of hairs; stamens opposite and epipetalous, as many as the petals, united with them at their very base; anthers dorsifixed, with 2 elongated locules dehiscing with a common longitudinal slit, filament short and stout; ovary half-inferior, tricarpellar; with stout style, stigma blunt, weakly 3-lobed; ovarian cavity simple, with greatly contorted placenta apically bearing 2 pendent anatropous and unitegmic ovules; glandular disk with large, dark green coloured, erect and obtuse lobes alternating with the petals; receptacle broad. Fruit a reddish, globular, rugose pseudodrupe, divided into 4–5 longitudinal parts easily separating at maturity; the fleshy layer of the pericarp is formed from an expanded nectary disk and the stony layer is part of the mesocarp. Seed solitary, globular, “naked” —the integument disintegrates during development—, embryo ellipsoid, with two strap-shaped cotyledons with abundant chloroplasts and starch grains.

Distribution and habitat:— This subspecies is endemic to the Pampean biogeographic province in the Eastern Pampean and Uruguayan districts ( Morrone 2017; Arana et al. 2017), known from Southern Brazil, Uruguay and eastern Argentina (east of Entre Ríos and northern Buenos Aires). Jodina rhombifolia subsp. rhombifolia is endemic to district of Espinal of Pampean biogeographic province, and also from Chaco biogeographic provinces from Neotropical region and Monte from South American transition zone ( Fig. 3 ).

Etymology:— We dedicate this subspecies to the late Prof. Dr. Elías Ramón de la Sota (1932–2014), our botanist teacher, who guided the studies of this interesting taxon and suggested the existence of two different entities.

Remarks:— Field observations made of living plants from the entire distributional range suggested differences in venation and colour of leaves between both subspecies. In Jodina rhombifolia subsp. rhombifolia leaves the delicate venation is not prominent; also, the leaves are chiefly glaucous, contrasting with J. rhombifolia subsp. delasotae , where the leaves are mostly dark green with prominent, protruding venation. However, leaf colour alone may not be conclusive. It varies to some degree on the same plant. Both, wax deposits and pigment characters need further comparative study.

Nomenclatural considerations:— Concerning the synonyms of the present subspecies, when de Candolle instated the variety Ilex cuneifolia L. var. bonariensis , he based his decision in the variety β created by Lamarck (1789) who cited in the protologue a specimen of Commerson from Buenos Aires (“a trouvé cette plante à Buenos Ayres ”). After a search in P we were able to find a Commerson specimen (P 00678750) from Jussieu’s herbarium that corresponds with the characters used by Lamarck and de Candolle to characterize the variety.As the protologue does not clarify whether Lamarck or even de Candolle studied only this specimen (the former cited only “ Buenos Ayres ”) and they used only this one for preparing the diagnosis without a reference to the specific number of the specimen in the protologue, it cannot be assumed that P 00678750 is the holotype ( Turland et al. 2018, Art. 8.3). Therefore, even though the specimen is sterile and correspond to a very young part of the plant, we here select P 00678750 as lectotype ( Fig. 3 ), as to fix the application of the name.

Considering the combination made by Miers (1878), he stated that: “A species first made known to us by Burmann in 1757, in his edition of Plumier’s “Plant. Amer.”, the locality not being stated; this has since been found to be Monte Video (“ Montevideo, Uruguay ”). An earlier date than the above must be assigned to this plant, as Burmann copied his drawing from Plumier’s unedited volumes. It is not known who gathered the illustrated plant, but it must have been some collector prior to the time of Commerson who visited Monte Video in 1767. The only collector known to us prior to that date is Dampier, who landed on that coast between 1680 and 1700, and who made botanical collections at every place visited by him. Linnaeus enumerated the plant in 1762, referring to Burmann as the authority. It is next described by Lamarck in 1789, who coupled with it his variety β (bonariensis), which is the following species.

Analysing this, we can conclude unequivocally that Jodina cuneifolia (L.) Miers is a synonym of Jodina rhombifolia subsp. delasotae , even though Miers established the difference with Jodina rhombifolia (in the same work) because the leaves of Jodina cuneifolia (L.) Miers are “not spinescent”, and cite the following specimen (that Miers explicitly stated he did not see, but he cited following Hooker & Arnott): “In regione Argentina, Rio Uruguay, lect. in 1830, Tweedie et Baird”. This specimen is exactly the same as the one cited in the protologue of Jodina rhombifolia , barcode E 00183319!.

Additional specimens examined:— ARGENTINA. Prov. Buenos Aires: * Isla Martín García, 1 October 1934, Cabrera 2863 (LP). * Bahía Blanca, Napostá Chico, 1873, De Candolle 6 (G). Pdo Gral Madariaga: Pinamar, 13 December 1950, Cabrera 10736 (LP). Zárate, entre Zárate y Las Palmas, 19 May 1946, Hunziker 1601 (CORD). Pdo Gral Lavall: San Clemente, Monte de la Tijera, 1 February 1939, Cabrera 4955 (LP). Laguna Marraco, 7 May 1879, Lorentz s/n (CORD). Prov. Entre Ríos: * Dpto Paraná: Parque Provincial Gral. San Martín, 15 September 1951, Correa & Bacigalupo s/n (SI

18069). Concepción del Uruguay, Ea de Cupalén, november 1877, Lorentz 1212 (CORD). BRASIL. * Edo. Río Grande do Sul: Pelotas, 14 April 1950, Gómes 107 (G). URUGUAY. * Dpto Colonia: Río San Juan, 2 November 1962, Torres & Ancibor 1087 (LP). * Dpto Minas: Arequita, 25 June 1911, Osten 5524 (CORD). * Dpto Flores: ruta 12 km 13, sobre arroyo Arias, 6 April 1994, Solís Neffa et al. 102 (CTES). Dpto Maldonado: Cerro Pan de Azúcar, 18 May 1937, Rosengurt 1854 (LP). Dpto Florida: Santa Clara, November 1926, Herter 238 (SI). Depto Santa Lucía: 21August 1897, Alboff s/n (LP 21076). Dpto Lavalleja: Penitente, 5 November 1933, Herter 93818 (SI). Cerca de la ciudad de Canelones, 1918, Felippone 2622 (SI).

Figures

FIGURE 3. Complete distribution of both subspecies of Jodina rhombifolia

FIGURE 4. Lectotype of Ilex cuneifolia L. var. bonariensis DC. (=Jodina rhombifolia subsp.delasotae), P.Commerson s.n. (P 00678750). Reproduced with permission of the Muséum national d’Histoire naturelle (MNHN).