Common name: Northern Striped Greenhood
Pterostylis divaricata (D.L.Jones & L.M.Copel.) L.M.Copel. & D.L.Jones APNI* Synonyms: Diplodium divaricatum D.L.Jones & L.M.Copel. APNI*
Description: Terrestrial herb.
Rosette leaves 5–9, lamina ovate, 0.5–1.4 cm long, 4–11 mm wide, margins entire or crisped; petiolate, petiole 3–12 mm long.
Scape to 24 cm high, with 2–6 dark green, obliquely spreading to appressed, lanceolate cauline leaves. Flower solitary (rarely 2) to 30 mm long, erect, translucent white with green and brown stripes, brown pigments more pronounced towards apex of galea, on free tip of dorsal sepal and on petals. Galea gibbous at base then erect before bending forwards in a graceful curve, apex nearly horizontal or decurved. Dorsal sepal 35–40 mm long, 10–12 mm wide boldly striped at base, green toward apex, and brown on the filiform point 5–8 mm long. Lateral sepals erect, tightly embracing the galea, leaving a narrow lateral gap; sinus protruding in a shallow curve to bulging when viewed from the side; flat with a shallow central notch when viewed from the front; free points to 25 mm long, filiform, erect, often curved forwards at the apex. Petals obliquely oblong-lanceolate, falcate 24–28 mm and 4.5–5.5 mm wide, margins not flared. Labellum attached to a short basal claw, erect, straight except for outward curve at apex, oblong-lanceolate, suddenly tapered above the middle, 10–12 mm long, c. 2.3 mm wide, subacture, the tip visible from the sinus in the set position;
Flowering: January to May
Distribution and occurrence: Endemic to the Northern Tablelands of New South Wales from Mummel Gulf National Park north to the New England Tablelands. Grows on sheltered slopes in moist sclerophyll forests and woodlands among grass tussocks, ferns and shrubs and in more exposed habitats on escarpments and among outcrops, known between 900 and 1200 m elevation.
NSW subdivisions: NT
Could be confused with Pterostylis abrupta but differs in not having a pronounced 'knee' in the synsepal under the hood rather there is a V-shaped sinus at the junction of the lateral sepals, and in having a narrower labellum whose apex is acute. Compare photos of P. abrupta and P. divaricata. Pterostylis divaricata was previously included in Pterostylis alata (Labill.) Rchb.f., but that taxon now considered to be endemic to Tasmania. In New South Wales this taxon has been treated as part of Pterostylis striata and as Pterostylis sp. aff. alata (New England).
Text by D.L. Jones, updated by Matt A.M. Renner (2 Dec 2019) based on Jones and Copeland (2016)
Taxon concept: Jones DL, Copeland LM (2016) Four new species of Orchidaceae from the New England Tablelands of New South Wales. Australian Orchid Review 81(3): 42.
APNI* Provides a link to the Australian Plant Name Index (hosted by the Australian National Botanic Gardens) for comprehensive bibliographic data
***The AVH map option provides a detailed interactive Australia wide distribution map drawn from collections held by all major Australian herbaria participating in the Australian Virtual Herbarium project.
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