Emilia blittersdorffii Beentje

Weber, O., von Blittersdorff, R. & Beentje, H. 2015. Eriospermum adpressifolium (Asparagaceae) and Emilia blittersdorffii (Asteraceae) — two new species from Tanzania with nearly identical leaves. Kew Bulletin 70: 28. DOI https://doi.org/10.1007/s12225-01

Morphology General Habit

Perennial herb with short-lived leaves and inflorescence from a tuberous underground part

Vegetative Multiplication Tubers

Tubers 2 – 5, cylindric to ovoid, 0.8 – 4 × 0.4 – 1.8 cm, surface smooth and pale to dark brown, flesh whitish, watery; with spreading fine roots from base; some tubers may lengthen to more than 4 cm

Morphology Leaves

Leaves of two types: basal leaves solitary or less often two (the smaller one below the larger), appressed to soil surface, fleshy/slightly succulent, round or nearly so, 1.5 – 6 (– 8.5) cm diam., glabrous, base amplexicaul, apex usually rounded but sometimes with a slight acute tip, upper surface reddish purple when young, turning bright green with reddish margin, glabrous; venation palmate with 5 – 7 main veins, visible from underneath, less so from above Cauline leaves 1 (– 3), broadly ovate to (upper) more oblong, 0.9 – 3 × 0.6 – 3 cm, glabrous, base cordate and semi-amplexicaul in lower leaves, to sessile and almost cuneate in upper, apex acute, green with reddish margin, glabrous; venation palmate, of 3 – 5 veins

Morphology Reproductive morphology Inflorescences

Inflorescence erect, at flowering time 9 – 45 cm tall with a glabrous stem branched in the upper ½ – 1/5 and with (1 –) 2 – 4 (– 5) discoid capitula per plant

Morphology Reproductive morphology Inflorescences Bracts Involucre

Involucre cylindrical, 5 – 7 mm long, 3 – 4 mm diam., of 10 – 12 phyllaries 5 – 7 × 1.5 – 2 mm, glabrous with slightly penicillate apex; subtending bracts 2, in uppermost part of stem just under capitulum, 2.5 – 4 × 0.4 – 0.7 mm

Morphology Reproductive morphology Flowers Florets

Florets white or cream, ± 22 in number, tube 2.5 – 3.8 mm, lobes 1 – 1.3 mm, glabrous, glandular; style arms penicillate-truncate

Morphology Reproductive morphology Fruits

Achenes cylindrical, 2.8 – 3.8 × 1 mm, ± 10-ribbed, pubescent; pappus of many barbellate bristles 4.5 – 5.5 mm long

Note

This taxon differs from all other known Emilia species in the habit, with a single or less often two almost round fleshy leaves appressed to the ground, and a flowering stem with only very few and small cauline leaves, combined with small underground tubers.

The specific name honours the discoverer of these two species, Robert von Blittersdorff.

While at least seventeen other Emilia species occur in this area (see Beentje et al. 2005; Beentje & Mesfin2004) our new taxon is unique in its leaves and roots; among the discoid taxa it comes closest to E. kivuensis (Muschl.) C. Jeffrey and E. simulans C. Jeffrey, from which it differs in corolla size and pappus length (3.5 – 4.1 mm and 4.5 – 5.5 mm respectively, as opposed to 7 – 7.5 mm and 3 – 4.5 mm in E. simulans) and floret colour (white or cream, as opposed to yellow or orange-yellow in E. kivuensis), and from both in achene size (2.8 – 3.8 mm, as opposed to 2.2 – 2.5 mm long in kivuensis and 2 mm in simulans).

At Mbizi Forest Reserve the plants appear after the first rains in mid-November, with the formation of the basal leaf on the surface. Some plants start growing the flowering stem, but the majority (±80 %) remain in the 1 (– 2) leaf stage. Flowers can be observed from December – January. Decay of the above ground organs (ground leaf) was observed from mid-April onwards, at the same time as the neighbouring Eriospermum basal leaf; vegetative reproduction takes place by formation and separation of new tubers.

Distribution

Only known from SW Tanzania. Map 1.

Ecology

Montane grassland on flat surfaces (seen in the foreground in Fig. 1E), with scattered termite hills; with Poaceae, Acanthaceae (Thunbergia sp.), Asteraceae (Berkheya, Gerbera, Aspilia, Vernonia etc.); Rubiaceae (Pentas, Fadogia, Galium etc.) Apocynaceae (Cryptolepis, Glossostelmambisiense) and Asparagaceae (Eriospermumkiboense, E. mackenii subsp. mackenii, E. adpressifolium). Soil a dark grey sandy clay/loam mixture. Altitude 2070 – 2300 m. Fig. 1E.

Conservation

Based on herbarium specimens and sight records, Emilia blittersdorffii has three subpopulations across an Extent of Occurrence (EOO) of 146 km2 with an Area of Occupancy (AOO) of 16 – 30 km2 (with a cell size of 2 – 2.4 km2); both values are below the threshold for Endangered. The EOO and AOO were calculated using the GeoCat tool (Bachman et al. 2011). 2 km2 is the cell size used for narrow endemics by the East African Plant Redlisting Authority of IUCN and 2.4 km2 is a cell size suggested by the GeoCat tool based on the longest diameter of the EOO polygon. The species is only known in the vicinity of the regional capital Sumbawanga. The meadows at the Ponda locality are at risk of land use change, being turned into maize fields (Fig. 1C). The localities at Malonje (about 13 km SSE of Ponda) and Illanga Hills (the eastern-most locality) are thought to be safer because the geological conditions are unfit for agricultural exploitation. Applying the Categories and Criteria of IUCN (2012), we assess this taxon as Endangered EN B1 ab (iii) + B2 ab (iii), assuming a decline in the quality of the habitat at the main of its three subpopulations.