Achyranthes annua Dinter, 1917

Sukhorukov, Alexander P., Kushunina, Maria, Nilova, Maya V., Baider, Cláudia & Sennikov, Alexander N., 2024, Africa and Arabia encompass a much greater species diversity in the Achyranthes aspera aggregate (Amaranthaceae, achyranthoid clade): Evidence from morphological and chorological data, PhytoKeys 250, pp. 21-94 : 21-94

Achyranthes annua Dinter , Repert. Spec. Nov. Regni Veg. 15: 82 (1917).

≡ Achyranthes argentea var. annua (Dinter) Suess. , Mitt. Bot. Staatssamml. München 1: 152 (1952).

≡ Achyranthes aspera [var. sicula] f. annua (Dinter) Cavaco , Mém. Mus. Nat. Hist. Nat. 13, ser. B (Botanique): 122 (1962).

= Achyranthes argentea var. viridescens Moq. in DC., Prodr. 13 (2): 315 (1849). Lectotype (designated here): [ Egypt] Cairo, Rudach [Roda] Island, [1818], F. W. Sieber s. n. (G-DC [image!]; isolectotypes M 0241528 !, M 0241529 !, K! [left-hand specimen, mounted together with A. sicula from Tanger, Morocco]).

= Achyranthes asperoides Pires de Lima , Brotéria. Sér. Bot. 19: 116 (1921). Lectotype (designated here): Mozambique. Na planície inculta junto de Palma, 26 February 1917, A. Pires de Lima 118 ( PO 69282 – image!; isolectotype PO 69283 – image!).

= Achyranthes aspera f. annulosa Suess. , Mitt. Bot. Staatssamml. München 1: 69 (1951). Holotype: Uganda, Ishasha , 4000 ft, November 1946, J. W. Purseglove 2284 ( K!).

= Achyranthes aspera [f. annulosa] subf. angustifolia Suess., Mitt. Bot. Staatssamml. München 1: 69 (1951) . Holotype: Sierra Leone, [Southern Prov.,] Njala , 28 December 1932, F. C. Deighton 2584 ( K 000243721 !).

– Achyranthes argentea auct.: Berhaut (1971).

– Achyranthes aspera var. argentea auct.: Hauman (1951), Cavaco (1953), Sunding (1973).

– Achyranthes aspera auct. in herb. div.

– Achyranthes aspera var. sicula auct.: Boudet and Lebrun (1986), Barry and Celles (1991), Lebrun et al. (1991), Audru et al. (1994), Townsend (1985, 1988, 1993 b, 2000), Miller (1996), Wood (1997), Germishuizen and Meyer (2003), Mapaura et al. (2004), Setshogo (2005), Figueiredo and Smith (2008), Brundu and Camarda (2013), Klaassen and Kwembeya (2013), César and Chatelain (2019), Odorico et al. (2022), Gosline et al. (2023).

– Achyranthes sicula auct.: Podlech (1966), Lebrun (1973), Peyre de Fabregues and Lebrun (1976), Hassan et al. (2023).

Type.

Namibia, [Otjozondjupa Region] Otjihua b. [y] Okandja Dtr. [District] Eahero [Farm], Dinter 3303 (B, destroyed) . Neotype (selected here): Namibia, [Oshikoto Region] Tsumeb, April 1934, Dinter 7434 ( K 005771734 !). Fig. 8 .

Description.

(Fig. 9 ). Annual, rather delicate herb, 20–100 (150) cm tall, not rooting; stems four-angled; lateral branches at acute angle with the main axis; leaf petioles 10–30 mm long, blades 20.0–80.0 × 10.0–60.0 mm, ovate, base truncate, tip ± attenuate, green, often turning red later, sometimes gray or pale green abaxially because of abundant silvery and appressed hairs, pendulous at night (at least in cultivation indoors); young leaves often with small red gland-like outgrowths on the veins adaxially (Fig. 9 C – E ) turning yellow and then pale white (indoor cultivated plants); inflorescence with ± equal main and lateral branches, with fruits rather distant at least in lower part; bract 1.5–2.0 mm long, bracteoles 2.0–3.0 mm long, pinkish, reflexed; perianth 3.0–3.5 (3.6–4.1) mm long, segments ± equal, one-veined with indistinct two lateral veins; stamens 5 with white or mauve filaments, anthers 0.15–0.25 mm long, yellow or pink, pseudostaminodes 0.5–1.2 mm long, apically ± fimbriate, white; style with stigma 0.5–0.8 (1.0) mm long; fruit (without style) 1.0–1.5 (1.8) mm long.

Taxonomic note.

Dinter (1917) described the species from Namibia and correctly noted that there are no intermediates between A. aspera and A. annua . However, the characters mentioned in the protologue – life form and inflorescence length – cannot be considered as delimiting traits. Both A. annua and A. aspera are annuals, although the latter species often resembles a perennial herb reaching 2 m tall and having long (up to 70 cm) inflorescences under favorable conditions (e. g., in a humid climate with enough precipitation). Habitually, A. annua is similar to A. abyssinica and A. sicula but differs by the minute anthers and much shorter styles. In addition, A. annua has leaves usually green on both sides, but sometimes their abaxial surface may be pale green or gray due to abundant simple hairs, especially in the populations growing in the Desert and Sahel zones. The name Achyranthes annua was not retained after its description ( Dinter 1917: 82). Podlech (1966) synonymized it with A. sicula , mentioning that A. sicula in Namibia is an annual plant. The recent checklist of Namibian plants ( Klaassen and Kwembeya 2013) did not include A. annua , with only a single species with two varieties listed ( A. aspera var. aspera and var. sicula). Our study reveals that A. annua is not only present in Namibia but is widely distributed across semi-arid regions of Africa reaching up to the Arabian Peninsula.

The gland-like outgrowths on the leaves (Fig. 9 C ) were detected only in some individuals of A. annua cultivated indoors; they were not observed in other species of the genus.

Nomenclatural notes.

The type of Achyranthes annua , previously kept at B, was lost during the Second World War, and no other original material has been traced in other herbaria visited or digitized. There are no duplicates of A. annua in the HBG herbarium, which contains many duplicates of K. Dinter (pers. comm. M. Schultz). Nevertheless, the first author ( APS) has found a specimen collected and labelled by K. Dinter in K, which is selected here as a neotype.

Moquin-Tandon (1849) cited two gatherings of A. argentea var. viridescens Moq. (“ prope Catanam ”, Heldreich; “ in Aegypto ”, Sieber) in personal collections of Poiret and Candolle, which are, therefore, syntypes. A specimen collected by Sieber and kept at G-DC is designated as lectotype here. This specimen was collected in 1818, when Sieber travelled across Crete, Egypt and Palestine ( Sieber 1823), and commercially distributed within a set of dried specimens of 230 species in 1819 ( Sieber 1821).

Pires de Lima (1921) cited a single gathering in the protologue of A. asperoides, Pires de Lima 118 , but the original material also comprises an uncited gathering, Pires de Lima 306, which was collected on another date. The cited collection is therefore not the holotype but a syntype, and lectotypification is warranted in this case. The plants collected are rooting at the lower nodes, with long lateral inflorescence’s branches. Such specimens are sometimes present in A. annua , but the exact measurements of reproductive characters are not known yet. In any case, the species cannot be synonymized with A. acuminata , A. aspera , or A. porphyrostachya .

Habitat.

A typical shade-loving plant usually collected in Vachellia – Commiphora bushlands (in East Africa), sometimes in rocky, sandy, volcanic habitats or in degraded plant communities in drier regions at elevations of 0–2400 m a. s. l. Dinter (1917) also indicated that A. annua is a common plant in under the canopy of Vachellia bushlands in SW Africa [ Namibia]. N. M. Otto (in labels at herb. M) noted that A. annua (as A. aspera ) is also common in KwaZulu-Natal ( South Africa) as a weed in cultivated areas, where the farmers called it “ wild buckwheat ”. Reports of the common presence of A. aspera in subcanopy communities in the tropical part of South Africa ( Leistner 1996) should probably belong to A. annua . Plants of this species are eaten by livestock.

Distribution.

(Fig. 10 ; see also Appendix 1). Africa: Angola, Benin, Botswana, Burkina Faso, Burundi, Cameroon, Cape Verde, Central African Republic, Chad, Djibouti, DR Congo, Egypt, Eritrea, Eswatini, Ethiopia, Gambia, Ghana, Guinea, Guinea-Bisau, Kenya, Lesotho, Liberia, Madagascar, Malawi, Mali, Mauritania, Mozambique, Namibia, Niger, Nigeria, Réunion, Rwanda, Senegal, Sierra Leone, Somalia, South Africa, South Sudan, Sudan, Tanzania, Togo, Uganda, Zambia, Zimbabwe.

Arabian Peninsula: Oman, Saudi Arabia, Yemen.

General distribution.

Africa and Arabia.

Figures

Figure 8. Neotype of Achyranthes annua (Namibia, Oshikoto Region, Tsumeb, April 1934, Dinter 7434, K 005771734). The image was provided by RBG Kew (available at http://specimens.kew.org/herbarium/K005771734).

Figure 9. Achyranthes annua A typical habitat with Vachellia trees, Manyara Region, Tanzania B an indoor cultivated plant in vegetative stage (grown from seeds from Manyara Region, Tanzania) C adaxial side of the leaf with red gland-like outgrowths on the veins (indoor cultivated plant) D close-up view of gland-like outgrowths and simple hairs E cross-section of a leaf showing bifacial anatomy and structure of an outgrowth. Scale bars: 100 µm (D); 0.5 mm (E). Photographers: A – D: A. Sukhorukov, E M. Nilova.

Figure 10. Distribution map of Achyranthes annua.