Streptocarpus, Lindl.

Fischer, Eberhard & Darbyshire, Iain, 2021, Five new species of Streptocarpus (Gesneriaceae) from Katanga, D. R. Congo, Plant Ecology and Evolution 154 (2), pp. 264-280 : 277

Key to the acaulescent species of Streptocarpus in Central Africa (D.R. Congo, Rwanda, Burundi)

1. Several leaves of similar size in a rosette, corolla pale pink with wine-red tube and wine-red spots at throat, corolla tube with long blunt unicellular hairs on the floor within, leaf margin entire ................ .................................................................... S. rhodesianus S.Moore (D.R. Congo, Zambia, Angola)

1’. Leaves solitary or several leaves with one large and several smaller leaves, corolla white, blue or purple, corolla tube lacking long blunt unicellular hairs on the floor within, leaf margin crenate or dentate .................................................................................................................................................. 2

2. Throat of corolla distinctly compressed from both sides....................................................................... ...................................................................... S. malachiticola Eb.Fisch. & I.Darbysh. (D.R. Congo)

2’. Throat of corolla not compressed......................................................................................................... 3

3. Corolla 8–15 mm de long; rhizome, base of leaves and peduncle covered by woolly brown hairs.... 4

3’. Corolla usually more than 20 mm long; rhizome, base of leaves and peduncle without woolly brown hairs...................................................................................................................................................... 5

4. Corolla ca 15 mm long, ovary glandular-pubescent, capsule 25–30 mm long, epiphyte in montane forest ........................................................................................ S. masisiensis De Wild. (D.R. Congo)

4’. Corolla less than 10 mm long, ovary glabrous, capsule 10 mm long, on shaded rocks ........................ ................................................................................ S. burundianus Hilliard & B.L.Burtt (Burundi)

5. Corolla tube distinctly curved below inflated throat, corolla entirely white.......................................... .......................................................................................................... S. bindseilii Eb.Fisch. (Rwanda)

5’. Corolla ± straight or slightly curved, inflated or not towards throat, corolla blue or purple at least on the lobes, sometimes with white or dark purple spots ......................................................................... 6

6. Limb large in relation to tube, lower lip 17(–20) mm long, lobes violet, throat with yellow bar, tube often calcareous-white outside............................. S. wittei De Wild. (D.R. Congo, Zambia, Malawi)

6’. Limb very small in relation to tube, lower lip not exceeding 11–15 mm length, lobes and tube violet to blue, throat sometimes slightly whitish but never yellow................................................................ 7

7. Leaf orbicular, 25–27 × 24.5–26.5 cm, length/width ratio ca 1, corolla 2 cm long, slightly curved, ovary and style not exceeding 7 mm............ S. salesianorum Eb.Fisch. & I.Darbysh. (D.R. Congo)

7’. Leaf oblong and broadly ovate, 6–32 × 4–25 cm, length/width ratio between (1.3–)1.6–2.7, corolla (1.5–)2.2–4.3 cm long, slightly curved or straight, ovary and style (7–)15–22 mm long ................... 8

8. Corolla with similar color throughout, tube slightly curved, narrowing from a wider throat (see fig. 7 , lower lip of corolla 6–11 × 4–6 mm, staminodes 1.5–2 mm long ......................................................... ............................................................................. S. schaijesii Eb.Fisch. & I.Darbysh. (D.R. Congo)

8’. Corolla with lobes darker than tube, tube ± straight, not or only slightly narrowing from the throat (see figs 3 , 5 ), lower lip of corolla 3–8 × 3–7 mm, staminodes not exceeding 1 mm of length ................. 9

9. Corolla pale violet, throat pale violet to whitish-violet, ovary and style 21–22 mm long, capsule 50–70 × 1.5–2 mm ........................................................... S. bampsii Eb.Fisch. & I.Darbysh. (D.R. Congo)

9’. Corolla dark violet, throat dark violet, tube pale-violet, ovary and style 7–15 mm long, capsule 40–50 × 1–1.5 mm ......................................................... S. malaissei Eb.Fisch. & I.Darbysh. (D.R. Congo)

Figures

Figure 3 – Streptocarpus bampsii. A. Habit. B–C. Flowers.D. Corolla, dissected, showing stamens and staminodes. E. Corolla, lateral view. F. Stamens. G. Staminode. H. Hairs on corolla. From Bamps & Malaisse 8389. Illustration by Eberhard Fischer.

Figure 5 – Streptocarpus malaissei. A–B. Habit. C. Detail of inflorescence. D–E. Corolla. F. Corolla dissected showing position of stamens and staminodes. G. Stamens. H–I. Staminodes. K. Apex of ovary with style and stigma. L. Hairs on ovary. M. Young capsule. N. Mature capsule. A, C, D, F–N from Bodenghien 30, B from Malaisse 13795, and E from Bodenghien 18. Illustration by Eberhard Fischer.

Figure 7 – Streptocarpus schaijesii. A–B. Habit. C–D. Partial inflorescence. E. Flower, lateral view. F. Corolla dissected, showing position of stamens and staminodes. G. Stamens. H. Staminode. A, C–H from Schaijes 1695 and B from Malaisse 13809. Illustration by Eberhard Fischer.