Euphorbia schinzii Pax (1898: 739)

Bruyns, Peter V., Klak, Cornelia & Hanáček, Pavel, 2020, A review of the Euphorbia schinzii-complex (Euphorbiaceae) in southern Africa, Phytotaxa 436 (3), pp. 201-221 : 212-213

8. Euphorbia schinzii Pax (1898: 739) .

Type:— SOUTH AFRICA. Transvaal (Mpumalanga): Berea Ridge, Barberton, 3100’, 13 February 1891, Galpin 1297 (lectotype BOL! designated by Bruyns (2012: 228), isolectotype K!). Fig. 6 .

Discussion: —In the protologue of E. schinzii, Pax (1898) cited two specimens, Rehmann 4347 from Pretoria, South Africa (missing and not seen by N.E. Brown (1915: 364) either) and Galpin 1297 (BOL!, K!) from Berea Ridge at Barberton, South Africa (± 300 km east of Pretoria). Pax gave the branches as 3-angled, but that is certainly an error and the fourth angle must have been entirely hidden in the pressed specimens he saw. He also mentioned ‘ angulis lobatis podariis ’, i.e. branches angled with the tubercles projecting somewhat (‘lobed’). Since Rehmann 4347 is missing, Galpin 1297 was selected as the lectotype for E. schinzii by Bruyns (2012). In Galpin 1297 the branches were 150−175 mm tall (‘6−8 inches’), the tubercles are fused into angles, the spines are subtended by stipular prickles ± 2 mm long and the specimen was collected in flower in February. The relatively tall branches, continuous angles with decurrent but not continuous spine-shields, fairly prominent stipular prickles and sessile cyathia with ± sessile ovaries make it clear that Galpin 1297 is the same species as the type of E. complexa . Other recent collections from Barberton (e.g., Kluge 2281 (NBG)) are also identical to E. complexa .

Traditionally, small (mostly <150 mm tall), clump-forming members of this complex from around Pretoria (also westwards and northwards) have been referred to as Euphorbia schinzii . These have been taken as typical of E. schinzii ( White et al. 1941) , to the extent that White et al. (1941: 745), Fourie (1988: 91, 92) and Hargreaves (1994: 147) all gave the ‘ Type locality’ of E. schinzii as ‘Pretoria Distr.; hills near Pretoria’. These plants are variably, but often strongly rhizomatous ( White et al. 1941: Fig. 835, 836, 838, Hargreaves 1994: 153). The tubercles are fused into ± continuous though somewhat sinuate angles along the branches (sinuate when viewed from the side), the spine-shields are decurrent below the spines for 4−6 mm, stipular prickles are minute and the ovaries are ± sessile.

Since the name E. schinzii now applies to plants from Barberton which are identical to E. complexa , E. complexa is a synonym of E. schinzii . The plants from Pretoria (also westwards and northwards) are not identical to these and require a name. However, they are not always easily distinguishable from subsp. bechuanica (see below). Since they are separated by only rather weak and variable features, all three are now included as subspecies under E. schinzii .

Three subspecies are recognized and may be separated as follows:

1. Plant forming a robust shrub 15–50 × 15–200 cm, branches 8–12(–20) mm thick, not rhizomatous, spines 6–18 mm long............. ............................................................................................................................................................................... subsp. bechuanica

1. Plant forming a small clump 5–20(–30) × 8–50 cm, branches 6–12(–20) mm thick, often rhizomatous, spines 3–12(–17) mm long....................................................................................................................................................................................................2.

2. Stipular prickles 0.5–1 mm long, spine-shields broad and usually blackish........................................................ subsp. schinzioides

2. Stipular prickles 1.5–3 mm long, spine-shields slender and usually grey.................................................................... subsp. schinzii

Figures

FIGURE 6. Distribution of Euphorbia schinzii (inverted triangle = subsp. schinzii, circle = subsp. bechuanica, upright triangle = subsp. schinzioides).