Thesium, L.

Lombard, Natasha & Le Roux, M. Marianne, 2023, Thesium hispidifructum (Santalaceae), a New Hispidulous Species from Limpopo, South Africa and Notes on Enigmatic T. celatum, Taxonomy (Clifton, N. J.) 3 (1), pp. 95-108 : 106

3.2. Artificial Identification Key for T. celatum, T. hispidifructum and Eight Morphologically Similar Species

1a. Leaf exterior glabrous, or sparsely to densely verruculose; flower exterior glabrous (if verruculose then flower lobes ≥ 1.2 mm long)

2a. Leaves up to 15 mm long; bracts up to 7 mm long

3a. Inflorescences with solitary or subsolitary flowers; 1(–2) flowers per inflorescence T. burchellii

3b. Inflorescences racemose cymes; 4–16 flowers per inflorescence

4a. Placental column straight; fruit sessile, stipe absent T. gracilarioides

4b. Placental column twisted; fruit stipitate, stipe ± 1.2–2.0 mm long T. procerum

2b. Leaves up to 45 mm long; bracts up to 25 mm long

5a. Inflorescences spikate cymes or flowers solitary, pedicels/peduncles absent; involucral bracts present or absent T. celatum

5b. Inflorescences racemose cymes (flowers rarely solitary), pedicels/peduncles 1.3–25 mm long; involucral bracts absent

6a. Bracts up to 25 mm long, reaching well beyond the top of the flowers; flower lobes 1.2–1.7(–2.4) mm long

6b. Bracts up to 10 mm long, not reaching past the top of the flowers; flower lobes ± 0.75–1.25 mm long

1b. Leaf exterior hispidulous, hispid, puberulent or pubescent; flower exterior hispidulous, hispid, puberulent or pubescent

7a. Stems woody (up to 4 mm in diameter), up to 1 m tall T. hispidifructum

7b. Stems herbaceous (if woody then sprawling and ≤ 1.5 mm in diameter), up to 0.3(0.5?) m tall

8a. Inflorescences racemose cymes T. disparile

8b. Inflorescences spikate cymes

9a. Stems sprawling, divaricate; leaves spreading T. rufescens

9b. Stems erect, virgate; leaves ascending to adpressed T. transvaalense