Reichardia intermedia (Sch.Bip.) Ascherson (1867: 155)

Sicilia-Pasos, Guillermo, Arjona, Yurena, Padrón-Mederos, Miguel A., Reyes-Betancort, J. Alfredo, García, Ángel, Jay-García, Louis S., Tuero-Septién, Javier & Patiño, Jairo, 2024, Taxonomic assessment and historical context of Reichardia intermedia (Asteraceae) in the Canary Islands, Phytotaxa 676 (1), pp. 52-62 : 56-57

Reichardia intermedia (Sch.Bip.) Ascherson (1867: 155) . Picridium intermedium Schultz Bipontinus (1850: 451) .

Syntypes:— ITALY. Sicily: “Habeo e Sicilia: Jan!; Creta: Sieber!; Lusitania, in arvis primo vere, Martio, 1839: Welwitsch! n. 388; Hispania, in lutosis reg. calidae in monte Gibraltarico, 3 Apr. 1845: Willkomm! n. 570”. Of all the locations mentioned, it is presumed that the appropriate type locality is “Habeo e Sicilia: Jan!” for the reasons outlined in Gallego et al. (1980) .

Morphological description:—Annual, rarely biennial plant. Stems up to 60 cm, erect, herbaceous. Leaves often covered with white papillae, with spiny teeth along the margins. Basal leaves spatulate to oblanceolate, tapering into a short, broad petiole. Cauline leaves sessile and toothed; the lower ones oblanceolate and auriculate; the middle ones ovate-lanceolate, acuminate, cordate and amplexicaul; the uppermost ones bracteiform. Peduncles widened at the top. Involucre 6–19(–20) × 5–20 mm. Involucral bracts with a broad subterminal callus, sometimes transformed into a mucro up to 0.5 mm; the outer ones ovate, generally acuminate, cordate, with a scarious margin (0.35–) 0.5–1.1 mm wide; the middle ones ovate or oblong-lanceolate, acute, auriculate, with a scarious margin (0.2–) 0.4–1 mm wide; the inner ones triangular-lanceolate, slightly scarious. Flowers yellow, the outer ones sometimes with a reddish band on the back. Anthers yellow. External achenes 2.5–3.5 mm, more or less ovoid, with four transversely tuberculate ribs, brown; internal ones 3.5–6 mm, cylindrical or conically truncated, with longitudinal lines, whitish and smooth. Pappus 8–11(–14) mm ( Gallego et al. 1980).

Historical reports revisited:—Of the historical reports on the presence of R. intermedia from La Palma, La Gomera, Tenerife and Gran Canaria, we were only able to locate one of the vouchers. This voucher corresponds to a specimen from the location cited by Pitard & Proust (1908) for Gran Canaria (P02713782) ( Fig. 1 ). The morphological analysis determined that this voucher did not correspond to R. intermedia , but rather aligned more with R. tingitana . Moreover, the specimen collected by us in La Gomera (ORT 47922), whose location seems to correspond to what Knoche (1923) reported ( Fig. 1C ), belonged to R. intermedia , as it showed concordant achene characteristics following the dichotomous keys in Gallego et al. (1980) and Gallego (2017) ( Fig. 2 ). Lastly, the remaining locations reported in the literature were visited, but no population of R. intermedia was detected. Instead, we found in these locations individuals identified as R. tingitana or R. ligulata .

Phenology:—This species blooms and bears fruit from February to May ( Blanca et al. 2009).

Distribution, habitat and ecology:—The distribution of this species is restricted mainly to the Mediterranean Basin ( Gallego et al. 1980; Siljak-Yakovlev et al. 2017).As for its habitat and ecology, it is a species frequently present in dry and open habitats ( Gallego et al. 1980; Blanca et al. 2009; Gallego 2017).

Our study presents an updated distribution for R. intermedia within the archipelago, confirming its presence solely on La Gomera island, specifically within the Garajonay NP. This presents an intriguing aspect from the distributional perspective, as despite its typical occurrence in arid environments, as previously indicated, R. intermedia was observed in a locality within the Canary Islands distinguished by elevated precipitation and humidity levels. However, it is noteworthy that its presence is restricted to a specific site characterized by vegetation clearing.

Herbarium voucher information:— SPAIN. Canary Islands. La Gomera: Parque Nacional de Garajonay, Salto del Perro (28.123, -17.206), 1051 m, 04.04.2023, A.García & guards from Garajonay National Park 47922 (ORT).

Etymology:—The original description by Schultz Bipontinus (1850) lacks a dedicated etymology section. However, the species epithet intermedia suggests characters intermediate between R. tingitana and R. picroides , as mentioned by Schultz Bipontinus in its description.

Phylogenetic assessment:—A total of 23 ITS sequences were gathered and used for inference of the phylogenetic relationships, with 19 sequences sourced from GenBank and four sequenced for the present study. The ITS matrix had a length of 697 bp. Of the 324 (46.5%) variable characters, 276 (85.2%) were parsimoniously informative, excluding the indels. Both ML and BI phylogenetic analyses produced highly congruent results ( Fig. 3 ). Reichardia intermedia was strongly supported as a sister to R. picroides (PP= 100; BS= 1.0). This R. intermedia – R. picroides clade was in turn sister to the Canarian clade, which also included the non-endemic R. tingitana ( Fig. 3 ). The monophyly of R. intermedia was strongly supported in both ML and BI phylogenetic analyses (PP=100; BS=1.0).

Figures

FIGURE 1. Historical and current reported occurrences of Reichardia intermedia in the Canary Islands. A. Map of the Canary Islands including historical reported occurrences of R. intermedia. In the case of the record provided by Masferrer (TF), it is shown as being on the island of Tenerife since no specific locality was mentioned; B. Map of La Gomera showing both historical and the location of R. intermedia found in this study; C. Detail of La Gomera, where number 62 (highlighted in red) represents the locality in which R. intermedia is found (Knoche 1923).

FIGURE 2. Internal and external achene photographs of Reichardia species analyzed in the present study, highlighting key differences among them. 1a. Internal achene of R. crystallina; 1b. External achene of R. crystallina; 2a. Internal achene of R. ligulata; 2b. External achene of R. ligulata; 3a. Internal achene of R. tingitana; 3b. External achene of R. tingitana; 4a. Internal achene of R. intermedia; 4b. External achene of R. intermedia.

FIGURE 3. Maximum likelihood and Bayesian inference phylogenetic tree of Reichardia and the outgroups (Sonchus, Launaea and Lactuca) based on nuclear DNA ITS sequences. Support values are shown along the branches only when bootstrap values are> 80% for ML and/or> 0.96 for BI. Clade I groups the Eastern Mediterranean species; Clade II groups R. intermedia (indicating with * the specimen from La Gomera) and R. picroides; Clade III groups the species endemic from the Canary Islands, together with R. tingitana and R. gaditana. “//” indicates that the branch lengths between outgroup and ingroup taxa are shortened to improve the readability of the tree.