Decalepidanthus

Dickoré, W. Bernhard & Hilger, Hartmut H., 2015, Decalepidanthus (Boraginaceae) includes and antedates Pseudomertensia; a synopsis of the genus, Phytotaxa 226 (2), pp. 131-143 : 133

Key to the species of Decalepidanthus

1. Stamens long exserted from corolla tube; filaments 3–7 mm long, slightly to much longer than anthers........................................2

- Stamens included or only anther tips exserted from corolla tube; filaments to 2 mm long, much shorter than anthers....................3

2. Corolla lobes to 1–2 mm long, up to 1 / 3 the length of tube, triangular or ligulate, faucal scales absent. Filaments much exceeding corolla lobes, anthers orbicular in outline, 0.4–0.6 mm long. Leaves lanceolate, apex acute, ± densely appressed strigose. Vegetative shoots much elongating after flowering, to ca. 50 cm, and usually conspicuously overtopping infrutescence ........... D. parviflorus

- Corolla lobes 2–3 mm long, slightly shorter to about as long as tube, (narrowly) ovate, faucal scales distinct; filaments about as long as to slightly longer than corolla lobes, anthers oblong in outline, 0.8–1.2 mm long; leaves narrowly (ob-)ovate, obtuse, thinly appressedly or subpatently pilose, or ± glabrescent. Vegetative shoots slightly elongating after flowering, to ca. 20 cm, not or only slightly overtopping infrutescence ......................................................................................................................................... D. trollii

3. Corolla white. Lamina of rosette leaves truncate to cordate at base, rosettes small, diffuse. Rhizome thin, long creeping................ ........................................................................................................................................................................................ D. racemosus

- Corolla blue. Lamina of rosette leaves cuneate at base, rosettes ± densely tufted or more robust. Rhizome thick, short.................4

4. Corolla tubular or campanulate, rarely ± infundibuliform; corolla tube about as long as or slightly longer than limb. Style long exserted. Aerial stem usually well developed; cauline leaves 2–6.....................................................................................................5

- Corolla usually distinctly infundibuliform, tube slightly to distinctly longer than limb. Style included, about the length of tube, or shortly exserted. Aerial stem short or absent and plants ± scapose; cauline leaves 0–3....................................................................6

5. Corolla campanulate, corolla lobes ovate, faucal scales distinct. Anthers ovate in outline, 0.6–0.9 mm long. Cauline leaves 3–6, often ± crowded in lower half of stem, ± sessile or with a short petiole; acute. Indumentum appressed strigose. Nutlets lenticularovoid, glabrous, abaxially evenly convex; attachment scar small, ca. 0.5 mm wide...................................................... D. elongatus

- Corolla tubular or sometimes ± infundibuliform, corolla lobes narrowly ovate, faucal scales ± indistinct or absent. Anthers triangular-oblong in outline, 1.0– 1.7 mm long. Cauline leaves usually 2–4, ± evenly distributed along stem, often gradually narrowed into a long petiole; obtuse. Indumentum ± patently pilose or appressed strigose. Nutlets ± tetraedral, ± pilose adaxially and on apex, abaxial surface except apex forming a distinct, almost plane, glabrous ‘shield’; attachment scar large, ca. 1 mm wide .................................................................................................................................................................................. D. echioides

6. Plants usually with short stems; cauline leaves 1–3. Rosette leaves ± ovate, lamina up to 5 × 3 cm long, ± abruptly contracted into a petiole to about twice as long as lamina. Indumentum dense, of long, ± patent trichomes, often retrorse at base of stem, on petioles and abaxial leaf surfaces. Corolla tube 6–10 mm long. Nutlets ± pilose, lower half of abaxial surface glabrous; apex acute. Plants more robust, in moist forest habitats ............................................................................................................................ D. moltkioides

- Plants scapose or nearly so; cauline leaves 0–1. Rosette leaves ± lanceolate, lamina up to 3 × 1.5 cm long, cuneate at base or ± gradually contracted into a petiole usually not exceeding the lamina in length. Indumentum of short antrorse, appressed or patent trichomes or plants ± glabrescent. Corolla tube 8–25 mm long. Nutlets glabrous; apex ± long acuminate-exserted. Plants usually dwarfish, often forming densely congested cushions or mats, in alpine habitats......................................................... D. primuloides