Amaranthus sparganicephalus Thell.

Hassan, Walaa A., Al-Shaye, Najla A., Alghamdi, Salma, Korany, Shereen M. & Iamonico, Duilio, 2022, Taxonomic revision of the genus Amaranthus (Amaranthaceae) in Saudi Arabia, Phytotaxa 576 (2), pp. 135-157 : 144-145

6. Amaranthus sparganicephalus Thell. in Ascherson & Graebner, Syn. Mitteleur. Fl. 5: 312. 1914

Type (neotype, here designated):— OMAN, Dhofar, J. Qara, nr. Aqarnahawat , Acacia hollow, 880 m a.s.l., 19.09.1985, A. G. Miller 7693 (E00687024!, image of the neotype available at https://data.rbge.org.uk/herb/E00687024) .

Description:— Herbs, 0.7–6 cm tall, monoecious, annual (therophyte). Stems erect, glabrous (pubescent in the upper part), yellowish, simple or branched (branches sometimes decumbent). Leaves green to dark-green, ovate (1.5–5.5 × 0.6–3.0 cm), with entire margins, apex obtuse to retuse, mucronate, base cuneate, glabrous (short hairs on the nerves of the abaxial surface), long petioled (petiole up to 6.0 cm long). Synflorescences arranged in axillary spherical glomerules, ± 1 cm in diameter, brown to dark-brown. Floral bracts ovate (0.3–0.5 × ca. 0.2 cm), about 1/2 times shorter than the perianth, acute to acuminate, mucronate. Staminate flowers with 3 tepals, green, ovate-lanceolate; stamens 3. Pistillate flowers with 3 tepals, green, ovate-lanceolate (1.0–1.3 × ca. 0.3 mm), with obtuse apex, median vein green; stigmas 2. Fruits arranged in stellate heads (divergent capsules), each one brown, as a double cone (2.75–3.25 × ca. 1.5 mm), longer than the perianth, the half base longitudinally sulcate, dehiscent with point of junction of lid and base cristate-crenulate. Seeds lenticular (1.2–1.5 mm in diameter), black.

Iconography:— Townsend (1985: 33, Fig. 6 ).

Phenology:— Flowering time from march to april.

Habitat and elevation:— Uncultivated land, around 2000 m a.s.l.

Chromosome number:— Not still counted.

Chorology:— Species native to eastern tropical Africa ( Djibouti, Eritrea, Ethiopia, Kenya, Somalia, Sudan, Tanzania), Arabian Peninsula ( Saudi Arabia, Yemen, Oman), and Socotra ( POWO 2022b and literature therein).

Occurrence in Saudi Arabia ( Fig. 6 ): — Riyadh.

Typification of the name Amaranthus sprganicephalus :— Amaranthus sparganicephalus was validly published by Thellung (1914: 312, a note) by a short diagnosis (in german) in which the following two characters were highlighted: the shape of the fruiting glomerules (which resembles those of the members belonging to the genus Sparganium L.; the specific epithet “ sparganicephalus ” derives from this feature) and that of each fruit (“polyedrisch abgeflachten” = “polyhedral flattened”); a morphologic comparison with A. angustifolius Lam. (currently A. graecizans subsp. graecizans ) and A. macrocarpus Benth. was also given. Finally the provenance (“tropischen Africa ... und Arabiens” = tropical Africa and Saudi Arabia) and three specimens (“ Abessinien: Massaua: Hildebrandt n. 716!; ostafrican. Grabenrand, 1904, Merken! ... “Chedrasch et Chedolia, Ehrenberg!”) were reported. According to the Art. 9.6 of ICN, these three citations are syntypes, original material for the name A. sparganicephalus (Art. 9.4 of ICN), and useful for the lectotypification purpose (Art. 9.3 of ICN).

Verdcourt (1967: 252) listed 16 specimens of Amaranthus sparganicephalus adding “ syntype ” after three of them, i.e. “ARABIA. Chedrasch and Chedolia, Ehrennberg (B)”, “ ERITREA. Massawa, Hildebrandt 716 (B)”, and “ TANZANIA. Grabenland, 1904, Merker (B)”. These three specimens was also cited (as “Types”) by Townsend (1985: 32) in his treatment of Amaranthaceae for the Flora of Tropical East Africa. According to Shenzen Code, neither Verdcourt (1967: 252) nor Townsend (1985: 32) proposed a correct typification, since they just re-listed the syntypes which was originally reported by Thellung (1914: 312) in the protologue. As a consequence, a lectoptypification is necessary. Note moreover that both Verdecourt and Townsend reported after the syntypes the symbol “†” which would indicate that the specimen was are no longer exsisting. R. Vogt (pers. comm.) informed one of us (DI) that no original material for A. sparganicephalus is preserved at B being probably lost/destroyed during the II World War. Lacking material useful for the lectotypification purpose (Arts. 9.3 and 9.4 of ICN), a neotyipfication is required under the Art. 9.8 of ICN. We here propose to designate, as neotype of the name A. sparganicephalus , a well preserved specimen at E (barcode E00687024) collected in Oman in 1985 which matches the Thellung’s description and the current application of the name (see e.g., Townsend 1985: 32).

Specimina visa selecta:— SAUDI ARABIA. Raidah Village near base of scarp. 25 km NNW of Abha, waste ground in villane, 07 April 1995, Collinette 9337 (E00121397!) .

Figures

FIGURE 6. Map of Amaranthus sparaganicephalus.