Acanthospermum hispidum DC.

Sheded, Mohamed G., Ayed, Fatma A. A., Radwan, Tarek A. A. & Ahmed, Dalia A., 2024, Contribution to Egypt’s Flora: new records from Nile Islands, South Valley, Egypt, Phytotaxa 660 (1), pp. 22-34 : 25

Acanthospermum hispidum DC. in Prodr. 5: 522 (1836)

Synonym: — Acanthospermum humile var. hispidum (DC.) Kuntze in Revis. Gen. Pl. 1: 303 (1891)

Voucher specimen: —Deposited in Aswan with Acc. No.11819 and TANE with Acc. No. 14267.

Description: —Annual herb, ± 60 cm tall, with dichotomous branching; single main taproot supporting many fine lateral roots. Stem covered in bushy and tiny glandular hairs. Leaves opposite, elliptic, obovate, and sessile; lamina oval and attenuates into petiole in basal third, base clasping; blade 1.5–8 cm long, 2–4 cm wide, 3-veined from just above base, both sides of leaf covered with stiff hairs; margin toothed (serrated to subentire) in upper two-thirds; apex obtuse and mucronate. Inflorescenses briefly stalked, solitary capitulum, located at intersection of each dichotomous branching; capitulum greenish, subtended by 5 bracts forming a circle; bracts of the capitulum composed of 5 bracts embracing circle of 5–10 fertile, ligulate, female flowers; center of capitulum with tight clusters of few sterile, tubulate, bisexual flowers,small, yellow, oblong acute at apex, hispid-pilose on margin, membraneous; marginal flowers 5–8, ligule of corolla elliptical with 3 teeth at apex, sparsely hispid-pilose, ca. 1.5 mm long, style lanceolate, obtuse. Disc flowers ca. 7, corolla hispid-pilose, ca. 1.5 mm long, lobes fairly long, ovaries glandular; pales of receptacle membranous, lacerate and acuminate at apically. Fruit wedge-shaped achenes grouped into star-shaped clusters; achenes angular, cuneate, compressed, densely uncinate-hispid, 4–5 mm long, with 2 more or less straight 3–5 mm long prickles at apex ( Fig. 2 ).

Habitat and human impacts on the recorded plant island: — Acanthospermum hispidum was recorded in Kubbanyia islands. It merged in 1982 and split in 2003. Elkubania1 was originally two islands that were close to merging to form one island. The islands have elongated since 1982. A small island (Elkubania2) tends to merge with Elkubania at the upstream end ( Raslan & Salama 2015). Cultivated fields, summer resorts, wadi and uninhabited sandy regions are the most abundant habitats of these isalnds. Recorded associated species are Alhagi graecorum Boiss. , Convolvulus arvensis L., Lantana camara L., Nidorella aegyptiaca (L.) J.C.Manning & Goldblatt, Solanum nigrum L., and Tephrosia purpurea (L.) Pers.

Human impacts on the island were represented by agricultural activities and tourism construction. The plant was recorded in cultivated fields, sandy plains, and wadi.

World native and introduced range: — Acanthospermum hispidum is native to Argentina Northeast, Argentina Northwest, Bolivia, Brazil North, Brazil Northeast, Brazil South, Brazil Southeast, Brazil West-Central, Colombia, Costa Rica, Cuba, Dominican Republic, El Salvador, French Guiana, Guatemala, Guyana, Haiti, Honduras, Leeward Is., Netherlands Antilles, Nicaragua, Paraguay, Peru, Puerto Rico, Suriname, Trinidad-Tobago, Venezuela, and Windward Is. ( POWO 2023), but it has spread rapidly to North America, Africa (e.g., Cape Verde, Ethiopia, Kenya, Tanzania, Uganda, Sierra Leone, Angola, Botswana, South Africa, Madagascar, Mauritius, and Reunion) ( Fig. 3 ).

Figures

FIGURE 2. Floral and vegetative parts of Acanthospermum hispidum. A. Life form andcapitula.B. Seed underOlympus SZ61 microscope with Toup camera (scale bar = 500 μm). C. Herbarium specimen [Fatma A.A. Ayed 11819 (ASW, TANE, CAI)].

FIGURE 3. Distribution pattern (world native and introduced range) of the three newly recorded taxa in the world (designed by the Author).