Pelekium Mitt.

Phephu, Nonkululo, Rooy, Jacques Van & Van Wyk, Abraham E., 2013, New combinations and a key to the species of Pelekium (Thuidiaceae) in sub- Saharan Africa and the East African Islands, Phytotaxa 84 (2), pp. 60-64 : 63-64

Key to the species of Pelekium Mitt. in Africa

1. Plants mostly minute to small (stems ≤ 50 mm long); paraphyllia simple, short (usually ≤ 7 cells long).................. 8

- Plants medium-sized (stems> 50 mm long); paraphyllia simple to weakly branched, short or long (usually ≥ 8 cells long) ............................................................................................................................................................................. 2

2. Terminal cells of paraphyllia and stem leaves predominantly acute ................................................. P. ramusculosum

- Paraphyllia and stem leaf terminal cell mostly truncate .............................................................................................. 3

3. Stem leaves mostly not plicate; margins plane; apex broadly acute.............................................................. P. varians

- Stem leaves plane to weakly plicate; margins recurved below, plane above; apex acute, acuminate or apiculate ..... 4

4. Stem leaf apex long apiculate; seta strongly hispid...................................................................................... P. velatum

- Stem leaf apex acute or acuminate; seta smooth or roughened throughout................................................................. 5

5. Stems 2- or 3-pinnately branched; laminal cells uni- or bipapillose; perichaetial leaf shoulders ciliate; seta smooth .. ................................................................................................................................................................ P. chenagonii

- Stems 1- or 2-pinnately branched; laminal cells uni- to pluripapillose; perichaetial leaf shoulders ciliate or eciliate; seta roughened throughout 6

6. Stems 1- or 2-pinnately branched; laminal cells mostly unipapillose, mixed with bi- to pluripapillose ones; perichaetial leaf shoulders eciliate....................................................................................................................... P. thomeanum

- Stems 2-pinnately branched; laminal cells bi- to pluripapillose; perichaetial leaf shoulders ciliate ........................... 7

7. Paraphyllia few, mostly simple; stem leaves plane to weakly plicate ............................................ P. pseudoinvolvens

- Paraphyllia abundant, mostly weakly branched; stem leaves mostly plane .................................................. P. gratum

8. Plants wiry; stems irregularly branched; paraphyllia almost absent; stem leaf cells thin-walled .................. P. investe

- Plants not wiry; stems regularly branched; paraphyllia abundant; stem leaf cells thick-walled ................................. 9

9. Stems 2-pinnately branched; paraphyllia simple, short; laminal cells with 1–3 papillae; perichaetial leaf shoulders eciliate; seta rough at neck ......................................................................................................................... P. versicolor

- Stems 1-, 2-, or 3-pinnately branched; paraphyllia simple to weakly branched; laminal cells with 1 or 2 papillae; perichaetial leaf shoulders ciliate or not; seta smooth or rough at neck .................................................................... 10

10. Stems (1–)2(–3)-pinnately branched; paraphyllia abundant; perichaetial leaf shoulder eciliate; seta rough at neck..... ................................................................................................................................................................ P. contortulum

- Stems (1–)2-pinnately branched; paraphyllia few perichaetial leaf shoulders ciliate or not; seta smooth or rough at neck 11

11. Paraphyllia simple to weakly branched; stem leaves plane to weakly plicate; laminal cells uni- or bipapillose; perichaetial leaf shoulders eciliate; seta smooth ....................................................................................... P. intricatum

- Paraphyllia simple; stem leaves plane; laminal cells unipapillose; perichaetial leaf shoulders ciliate; seta rough at neck P. minusculum