Astragalus sect. Poterion Bunge, 1868

Khan, Amjad, Sultan, Amir, Zarre, Shahin & Ishaq, Kamran, 2023, Astragalus pseudoanisacanthus, a new species of section Poterion from northern Balochistan (Pakistan), Phytotaxa 622 (4), pp. 236-251 : 244

Key to species of Astragalus sect. Poterion Bunge

1a. Claws of the wings and keel are only attached basally to the staminal tube......................................................................................2

1b. Claws of the wings and keel attached to the staminal tube for 1/2–3/4 of its length .........................................................................8

2a. Stipule amplexicaul, connate throughout almost to the apex, shortly bilobed.................................. A. pachyrhachis Širj. & Rech.f.

2b. Stipules not amplexicaul or amplexicaul, free from each other .........................................................................................................3

3a. .................................................. Calyx longitudinally 8–12-nerved, its sinuses glabrous …………...............................…………. 4

3b. Calyx longitudinally (12–)14–40-nerved, its sinuses pilose ..............................................................................................................5

4a. Corolla pinkish to purplish, vexillum, 12–18 × 5.5–9 mm, legume 4–7 × (2.5–) 3–5 mm, ovate, unilocular, 1–2-seeded................. ......................................................................................................................................................................... A. anisacanthus Boiss.

4b. Corolla white, vexillum, 12–12.5 × 4–4.5 mm, legume 6–8 × 3‒4.5 mm, broadly ellipsoid, partially bilocular, 2–4 seeded ............ .......................................................................................................................... A. pseudoanisacanthus A. Khan, A. Sultan & Zarre

5a. Calyx longitudinally (12–) 15–25-nerved ..........................................................................................................................................6

5b. Calyx longitudinally 30–40-nerved....................................................................................................................................................7

6a. Calyx 8–13 mm long, fruiting calyx 10–14 mm long and 5–9 mm wide, narrowly ovoid or ellipsoid, slightly pink-suffused, teeth 1.5–3 mm long (in subsp. angustifolius even longer........................................................................................... A. calliphysa Bunge

6b. Calyx 10–15 mm long, fruiting calyx (13–) 15–20 mm long and 8–12 mm wide, broadly ovoid-ellipsoid to almost globose, often red, teeth 3–5 mm long............................................................................................................... A. porphyrophysa Bornm. & Gauba

7a. Inflorescences 1–2-flowered. Limb of the wings not expanded towards the apex. Limb of the keel oblong, 2–2.5-fold longer than wide. Style pilose only in the basal third. Legume laterally compressed............................................. A. spinosus (Forssk.) Muschl.

7b. Inflorescences 2–5-flowered. Limb of the wings are often expanded towards the tip. Limb of the keel obovate-triangular, less than twice as long as it is wide. The style pilose for 1/2 to 4/5 of its length. Legume dorsally compressed........ A. glaucacanthus Fisch.

8a. Stipules 3–8 mm long, amplexicaul, internodes equal in length or slightly shorter than stipules, stipules sparsely hairy or ciliate only along the margins .......................................................................................................................................................................9

8b. Stipules 1–3 (–4) mm long, semi-amplexicaul, internodes distinctly shorter, densely hairy in the first year..................................10

9a. Leaflets 4–6-pairs on the main stem, narrowly elliptic or narrowly obovate, upto 3.5 mm wide. Calyx sinuses narrow, densely pilose............................................................................................................................................................. A. russellii Banks & Sol.

9b. Leaflets 2–4 (–5)-pairs on the main stem, obovate to widely cuneate-obovate or elliptic to orbicular, 3–8 mm wide. Calyx sinuses wide, sparsely pilose or glabrous........................................................................................................................... A. bruguieri Boiss.

10a. Ovary and legume glabrous................................................................................................................................. A. baba-alliar Parsa

10b. Ovary and legume pilose ..................................................................................................................................................................11

11a. Calyx equally covered with short appressed hairs. In leaves with 2-pairs of leaflets, the lower pair of leaflets inserted in the middle of the rachis, the upper pair inserted close to the apex of the rachis................................................................... A. baba-alliar Parsa

11b. Calyx glabrous or irregularly and sparsely covered with short appressed hairs. In leaves with 2-pairs of leaflets, both pairs inserted in the lower half of the rachis ......................................................................................................................... A. fasciculifolius Boiss.