Veronica trifida Petrie

Low sprawling or creeping sub-shrub to 0.2 m tall. Stems prostrate, ascending at tips, eglandular-pubescent; hairs uniform. Leaf bud indistinct; leaves separating while very small, opposite-decussate to sub-distichous, erecto-patent. Lamina thin to sub-coriaceous, elliptic, obovate, oblong, oblanceolate, or spathulate, rarely sub-orbicular, 2–10 mm long, 1–7 mm wide, glossy green or bronze-green above and beneath; veins not evident; surfaces glabrous; margin sparsely glandular-ciliate, rarely some eglandular hairs as well, serrate, crenate or lobed; teeth or lobes in 1–3 pairs; apex obtuse, rounded, or sub-acute; base cuneate; petiole 1–2 mm long. Inflorescence a lateral raceme, 15–25 mm long; flowers crowded or distant, 2–3 or solitary and bibracteate; peduncle 2–10 mm long, all bisexual; bracts opposite or alternate, elliptic or obovate, >pedicels; pedicels sub-erect, 0.5–7.0 mm long, mixed glandular- and eglandular-hairy all around. Calyx lobes 4, rarely reduced 5^th lobe present, obtuse to sub-acute, 4.0–5.5 mm long, equal, glandular-hairy with a few eglandular hairs. Corolla 15–20 mm diameter; tube white, rarely purplish, greenish-yellow at the base, 3–4 mm long, < calyx, glabrous; lobes 5, sometimes 6, white, rarely purplish, erecto-patent to recurved, unequal, elliptic to obovate or orbicular, 6–11 mm long, obtuse to rounded; nectar guides absent. Stamen filaments white or greenish, 2–3 mm long; anthers purple, sometimes magenta or pink. Style glabrous, 2.5–4.0 mm long. Capsule angustiseptate, emarginate, glabrous or with a few glandular hairs, 4.5–6.0 mm long, 2.5–3.5 mm at widest point. Seeds ellipsoid to obovoid, flattened, smooth, pale brown to brown, 0.8–1.2 mm long.

Alpine seepages and flushes of melt-water associated with summer snow-banks, edges of water races, boggy ground. Recorded elevations range from 1070 to 1840 m.

Where the ranges of V. trifida and V. chionohebe meet (Garvie Mountains, Old Man Range) hybrids between them are quite frequent (Garnock-Jones & Lloyd 2004). Such plants are lax, softly woody sub-shrubs to about 5 cm tall; leaves entire, margin ciliate and glandular-ciliate; flowers solitary, axillary, bibracteate; pedicel c. 0.8 mm long; calyx 3-nerved with a few cilia, both glandular and eglandular, 3 mm long; calyx lobes 5, regular or 1 smaller, obovate-elliptic, with glandular and eglandular cilia (glandular distally); corolla rotate, 7 mm diameter, tube c. 2.5 mm (< calyx).

Flowers: December–February: fruits: January–April (and probably persisting longer).

2n = 42 (Hair 1970).

Veronica trifida is classified in V. subg. Pseudoveronica sect. Hebe and informally in the “snow hebe” group (Albach & Meudt 2010).

Analysis of ITS sequence data indicates V. trifida is sister species to V. densifolia, and its next nearest relative is V. spectabilis (and probably V. birleyi). These species are morphologically similar in growth form, leaf lobing (when present), inflorescences, five- to six-lobed corollas, and short stamens and styles. The ITS tree topology suggests this group is sister to a large clade of shrubby hebes, sun hebes and speedwell hebes, but field observations and phylogenetic analysis of chloroplast DNA indicate they hybridise with the cushion snow hebes, and that process probably includes chloroplast exchange. Thus cpDNA sequences of V. densifolia and V. spectabilis cluster with those of V. pulvinaris and V. thomsonii, whereas those of V. trifida cluster with V. ciliolata, V. chionohebe (with which hybrids are observed in the field), and another accession of V. thomsonii.

The leaves often dry black in herbarium specimens, but retain their glossy surface. The margins of the corolla lobes are finely fimbriate or erose.

The earlier V. trifida Gilibert, Flora Lithuanica 1, 121 (1785), based on a different type, is not a legitimate name because the work it is published in is listed in Opera Utique Oppressa (http://www.bgbm.org/iapt/nomenclature/code/saintlouis/0116AppendixV.htm).