Schoenus cuspidatus

Elliott, T. L. & Muasya, A. M., 2020, A taxonomic revision of Schoenus cuspidatus and allies (Cyperaceae, tribe Schoeneae) - Part 2, South African Journal of Botany 130, pp. 327-347 : 328-330

4. Key to the species in the Schoenus cuspidatus group (species without numbers are included in Part 1 the revision)

This is an updated, more comprehensive key than that pub-lished in Elliott et al. (2019), and thus, should be referred to when possible. In addition, we recommend also consulting Tables 1 and 2 when identifying specimens to help clarify ambiguities in characters.

1a. Proximal primary inflorescence bract conspicuously expanded at base; longitudinal veins at base of bract often prominent:

2a. Plant widespread throughout South Africa (usually found within 200 km of the S. and E. coasts) and appearing semi-succulent; basal leaves usually less than 150 mm in length:............................................................................... Schoenus auritus

2b. Plant restricted to granitic sites on the Cape Peninsula and not appearing semi-succulent; basal leaves usually greater than 250 mm in length:.................................................................................... Schoenus graminifolius

1b. Proximal primary inflorescence bract not conspicuously expanded at base (or slightly expanded as in S. compactus ); longitudi-nal veins at base of bract not prominent:

3a. Spikelets linear-lanceolate ( Fig. 1 in Elliott et al., 2019); nutlets narrow ellipsoidal ( Fig. 2 in Elliott et al., 2019):

4a. Plants usually greater than 350 mm in height; spikelets 4.5‒7.5 mm in length, often reduced sexually with only male or female organs present:................................................................................ Schoenus ligulatus

4b. Plants less than 340 mm in height; spikelets mostly less than 4.5 mm in length, bisexual spikelets always pres-ent:....................................................................................................... Schoenus exilis

3b. Spikelets lanceolate to ovate ( Fig. 1 in Elliott et al., 2019); nut-lets broad ellipsoidal ( Fig. 2 in Elliott et al., 2019):

5a. Spikelets lanceolate:

6a. Glume margins with reddish-purple streaks adjacent to the hyaline margins ( Fig. 3R in Elliott et al., 2019):

7a. Older leaves usually curled; membranaceous sheaths with reddish-purple streaks:.............................................................. Schoenus bolusii

7b. Older leaves usually straight; sheaths firm (i.e. not membrana-ceous) and red to brown in colour:................... Schoenus submarginalis

6b. Glume margins without reddish-purple streaks adjacent to the hyaline margins ( Fig. 3 in Elliott et al., 2019):

8a. Basal leaves reduced in length (usually a third to a quarter of culm length, never over half of culm length):............................ Schoenus crassiculmis

8b. Basal leaves well-developed in length (often over half of culm length):

9a. Spikelets 4.0 mm or less in length; glumes often scarious (i.e. thin and membranaceous):

10a. Plants usually occurring on sandstone substrates; base of culms and sheaths usually brown in colour (only with a tinge of red); leaves stiff and firm so that they are straight: ................................................................................... 1. Schoenus brunnescens

10b. Plants endemic to quartz patches on shale derived soils in the Overberg region of the Western Cape Province of South Africa; base of culms and sheaths usually reddish in colour; leaves lax (not stiff):............................................................................. Schoenus quartziticus

9b. Spikelets usually greater than 4.0 mm in length; glumes firm (i.e. solid):

11a. Plant (including leaves) firm and stiff; inflorescence reddishbrown in colour (often with an orange tinge); prophylls and prophyll mucros thickened and firm:

12a. Inflorescence relatively short and congested (i.e. compact), less than 35 mm in length; rachis between lower spikes relatively short so that clusters of spikes overlapping; primary inflorescence bracts some-times slightly widened at base:................................... 2. Schoenus compactus

12b. Inflorescence longer and not congested, greater than 35 mm in length; rachis between the lower spikes noticeably lengthened so that clusters of spikes only partially overlapping; primary inflores-cence bracts narrow at base:...................................... 3. Schoenus crassus

11b. Plant (including leaves) less firm and stiff so that often appearing lax, often with curled leaves; inflorescence dark brown in colour; prophylls and prophyll mucros not thickened:

13a. Leaves not proximally channelled, usually wide and flat:.............................................................................................. 4. Schoenus loreus

13b. Leaves proximally channelled becoming terete above:

14a. Plants endemic to grassland habitats on mountain slopes in the Kwazulu-Natal and Eastern Cape Provinces of South Africa, as well as adjacent areas of Lesotho; inflorescence with few primary inflorescence bracts so that it does not appear ‘bearded’; glume mucros short or absent (usually less than 0.5 mm in length):................................... 5. Schoenus galpinii

14b. Plants endemic to more southern and western South African locations; inflorescence with many inflorescence bracts developed so that it appears ‘bearded’; glume mucros longer and conspicuous (often greater than 0.5 mm):

15a. Lower glumes cuspidate (i.e. having a cusp or a short, firm tip) and relatively short compared to the length of the spikelet: ..................................................................................... 6. Schoenus cuspidatus

15b. Lower glumes aristate (i.e. with awns) and relatively long compared to the length of the spikelet (i.e. greater than one quarter to one third):

16a. Plants usually less than 360 mm in height, usually five or fewer spikes per panicle:..................................... 7. Schoenus graciliculmis

16b. Plants usually greater than 360 mm in height, usually more than five spikes per panicle:

17a. Plants usually greater than 630 mm tall and restricted to wet-lands on the Cape Peninsula of South Africa; inflorescence relatively long (greater than 50 mm) and wide (usually greater than 12 mm):.............................................................................. 8. Schoenus riparius

17b. Plants usually less than 630 mm tall and occurring off the Cape Peninsula of South Africa; inflorescence relatively short (less than 50 mm) and narrow (usually less than 12 mm):

18a. Plants occurring mostly on coarse-textured (i.e. sand sub-strates) along the southern coast of South Africa; spikelets reddish-brown to dark reddish-brown in colour ( Fig. 5I ): ................................................................................ 9. Schoenus australis

18b. Plants usually occurring on damp sites in grasslands from KwaZulu-Natal to adjacent regions of the Eastern Cape Province of South Africa; spikelets usually light reddish-brown in colour ( Fig. 4O in Elliott et al., 2019):............................................................... Schoenus limosus

5b. Spikelets ovate:

19a. Plants endemic to mountains regions of the southern Western Cape province of South Africa; sheaths loose; leaves appearing flat as they are usually not-channelled above lig-ule:........................................................................... Schoenus purpurascens

19b. Plants endemic to the Agulhas Plains region of South Africa; sheaths firm; leaves appearing terete as they are channelled above ligule:

20a. Spikelets with firm prophylls that often shine; prophyll awns greater than 3.0 mm; base of culms terete and with sheath not holding several leaf bases together:.............................................. Schoenus prophyllus

20b. Spikelets with prophylls that are not firm and shining; prophyll awns less than 2.4 mm long; base of culm flattened and with sheath hold-ing several leaf bases together:................................................... Schoenus calceolus

Figures

Fig. 1. A phylogenetic reconstruction showing the placement of the three major groups of Southern African Schoenus (highlighted in grey) relative to other species in the genus (figure adapted from Viljoen et al. (2013) and Elliott and Muasya (2017)).

Fig. 2. Growth forms and inflorescences of two species from the S. cuspidatus and allies group: A—S.cuspidatus (caespitose growth form), B—S.cuspidatus (inflorescence), C—S.crassus (inflorescence), D—S.cuspidatus (caespitose growth form).All photos were taken in the field by T.L.Elliott with a Sony RX100 II camera.

Fig. 3. Examples of plants from five species of the S. cuspidatus and allies group found in Southern Africa, showing the corresponding inflorescences beneath each plant: A and F—S. brunnescens; B and G—S.compactus; C and H—S.crassus; D and I—S.loreus; and E and J—S.galpinii. The black scale bar adjacent to the inflorescence in J represents 10 mm.

Fig. 5. Examples of spikelets from nine species of the S. cuspidatus and allies group found in Southern Africa:A—S. brunnescens; B—S. compactus; C—S. crassus; D—S.loreus; E—S. gal- pinii; F—S.cuspidatus; G—S.graciliculmis; H—S.riparius; and I—S.australis. The black scale bar represents 1 mm.

Fig. 4. Examples of plants from four species of the S.cuspidatus and allies group found in Southern Africa, showing the corresponding inflorescences beneath each plant: A and E—S. cuspidatus; B and F—S.graciliculmis; C and G—S.riparius; and D and H—S.australis. The black scale bar adjacent to the inflorescence in H represents 10 mm.