Lepidium banksii Kirk, Stud. Fl. N. Z, 35 (1899)

Lange, P. J. de, Heenan, P. B., Houliston, G. J., Rolfe, J. R. & Mitchell, A. D., 2013, New Lepidium (Brassicaceae) from New Zealand, PhytoKeys 24, pp. 1-147 : 24-27

Lepidium banksii Kirk, Stud. Fl. N. Z, 35 (1899)

Type Collection:

"SOUTH Island: Queen Charlotte Sound and Astrolabe Habrour, A. Richard, l.c."

Lectotype

( Fig. 21 , designated here): Herbarium Richard, Paris!

Etymology.

Although Kirk (1899) did not explain his choice of epithet, ' banksii ' commemorates Sir Joseph Banks FLS, FRS (1743-1820) who together with Dr Daniel Solander made the first gatherings of New Zealand plants to be described by European botanists during the Endeavour voyage of discovery (1768-1771).

= Lepidium banksii var. ovatum Kirk, Stud. Fl. N. Z., 35 (1899)

Lectotype

(fide Allan 1961): Northwest Bay, Pelorus Sound, J. Rutland s.n., n.d., WELT SP079012!

Etymology.

Although Kirk (1899) did not explain his choice of epithet, the protologue makes it clear that " ovatum " was chosen to refer to the shape of the mature silicles.

Note:

The key provided by Kirk (1899, p. 34) used the name " Lepidium forsteri " instead of Lepidium banksii . This is considered to be a nomen nudum.

Description

( Figs 22 -25 ). Tap-rooted, strongly pungent smelling, perennial herb. Growth habit dense, stems closely placed, 20-50 cm tall. Stems upright to spreading, stout, barely flexuous; mature stems woody, 100-500 × 3-8 mm, often devoid of foliage on middle and lower parts of stems. Leaves glabrous, coriaceous, green, planar, rosette and stem leaves usually withering, variable in size and shape. Leaves of young and vigorous plants and stems: lamina 20-40 × 6-15 mm, oblanceolate-spathulate, obovate; apex obtuse, often with up to 3 or 4 teeth; margin coarsely serrate, with 15-21 pairs of teeth; teeth up to 2.0 mm deep, irregular in size, protruding beyond leaf outline; base attenuate to cuneate, petiole distinct; petiole up to 35.0 × 1.3-2.8 mm, channelled. Leaves of mature plants and cauline stems: lamina 8-25 × 3-6 mm, linear-oblanceolate, obovate; apex obtuse to truncate, often with up to 3 or 4 teeth; margin serrate in upper half, up to 7 pairs of teeth; not overlapping, up to 1.5 mm deep, often protruding beyond leaf outline; base attenuate to cuneate, usually tapering to ± distinct petiole, sometimes appearing sessile; petiole up to 8.0 × 1.0-1.8 mm, channelled. Inflorescences terminal and lateral, racemose, 20-80 mm long, rachis 0.6-1.4 mm diam., glabrous or sometimes with pale clavate hairs; pedicels 5-8 mm long, erecto-patent, with pale clavate hairs on adaxial surface, hairs 0.1-0.15 mm long. Flowers 4.0-4.5 mm diam. Sepals 4, saccate, overlapping at base, green, apex obtuse, margin white, shape and size dimorphic; lateral sepals 1.6-2.1 × 1.1-1.5 mm, orbicular, glabrous; median sepals 1.5-1.9 × 0.9-1.1 mm, broadly elliptic, abaxial surface glabrous or sparsely hairy, hairs 0.2-0.4 mm long. Petals white, 1.8-2.0 × 0.1-0.9 mm, erect, claw indistinct; limb narrrowly obovate, elliptic or filiform, often irregular in shape, apex obtuse to subacute. Stamens 4, ± equal lengths, 1.2-1.7 mm long, base 0.6-0.9 mm wide; anthers 0.4-0.7 mm long, yellow or sometimes violet. Ovary 1.4-1.6 × 1.0-1.6 mm, broadly ovate, green, apex round or sometimes weakly shouldered; style 0.2-0.3 mm long, cylindrical below, spreading at apex; stigma 0.45-0.5 mm diam. Nectaries 4, 0.2-0.4 × c. 0.1 mm, oblong, green. Silicles cartilaginous when fresh, coriaceous when dry, 4.5-5.5 × 4.0-5.0 mm, broadly ovate, apex notched, base cordate, valves green maturing yellow-green, glabrous, slightly winged; style 0.2-0.3 mm long, exserted. Seeds 1.8-2.3 × 1.0-1.2 mm, obovate or obovate-elliptic, brown to orange-brown, not winged. FL Nov-Jan. FR Nov-Jan.

Representative Specimens.

New Zealand (South Island): Tennyson Inlet, Tawa Bay, January 1910, E. Phillips-Turner 93, (AK 100087); Kenepuru Head, Pipi’s Beach, 1917, J. H. MacMahon s.n., (WELT SP030112); Kenepuru, n.d., n.c.,, (WELT SP030113);?Queen Charlotte Sound, n.d., J. H. MacMahon s.n., (WELT SP081929); Boulder Bank, November 1908, F. G. Gibbs s.n., (CHR 81737); Abel Tasman National Park, Totaranui Headland, December 1961, A. E. Esler s.n., (AK 218197); Abel Tasman National Park, Totaranui Headland, 27 January 1963, A. E. Esler s.n., (CHR 181143); Abel Tasman National Park, Totaranui Point, 12 January 1984, D. R. Given 13871 & A. D. Given, (CHR 509034); Abel Tasman National Park, Totaranui, 12 January 1986, D. R. Given 14106, (CHR 420352); Abel Tasman National Park, Totaranui Trig, 9 January 1984, D. R. Given 13505 & B. A. Duncan, (CHR 416178); Abel Tasman National Park, Separation Point, 28 January 1997, P. J. de Lange 3249 & G. M. Crowcroft, (AK 231008); Karamea, 28 January 1985, P. Wardle s.n., (CHR 446772); Bird Island, Waimea Estuary, 1946, C. Baas s.n., (CHR 278958). Cultivated (New Zealand). Landcare Research experimental nursery, Lincoln, ex Totaranui, Nelson, 17 November 2005, P. B. Heenan s.n., (CHR 504666); Landcare Research experimental nursery, Lincoln, ex Abel Tasman National Park, 6 August 2006, P. B. Heenan s.n., (CHR 609830).

Distribution

( Fig. 15 ). Endemic. New Zealand, South Island, Marlborough Sounds (Queen Charlotte, Kenepuru and Pelorus Sounds), Nelson (Waimea Estuary, Totaranui, Separation Point, Wainui Inlet), north-west Nelson (Karamea).

Recognition.

Lepidium banksii is recognised by the clavate hairs on the pedicels ( Fig. 24A ), mostly filiform petals, styles that spread at the apex into a broad plate ( Fig. 24B ), and silicles that have a prominent apical notch ( Fig. 25 ). In comparison, the styles of the other Lepidium species except for Lepidium seditiosum , are cylindrical for their whole length.

Ecology.

Lepidium banksii is a strictly coastal species favouring rubble slopes, boulder beaches, exposed rocky headlands ( Fig. 22 ), and sparsely vegetated cliff faces usually near penguin colonies or low lying, estuarine shell banks and sand and shell barrier islands used as high tide roosts by wading birds.

Conservation Status.

Lepidium banksii is currently listed as 'Threatened/Nationally Critical CD, EF’ by de Lange et al. (2009). Both de Lange (2006) and Courtney (2009) describe the conservation management of this species, noting that there are probably no naturally occurring plants of Lepidium banksii left in the wild, with all those known the result of deliberate plantings and sowing of seed. As such, the qualifier ‘EW’ (Extinct in Wild) should be added to the current threat listing. The most recent census of the numbers of Lepidium banksii present in the ‘wild’ records 113 plants ( Courtney 2009). Survival of this species is now completely dependent on direct hands-on management ( de Lange 2006; Courtney 2009).

Figures

Figure 15. Distribution of Lepidium aegrum, Lepidium amissum, Lepidium castellanum (Kermadec Islands only), Lepidium banksii, and Lepidium crassum.

Figure 21. Lectotype of Lepidium banksii.

Figure 22. Young wild plant of Lepidium banksii (image: S. Walls).

Figure 24. (A) Pedicel of Lepidium banksii showing hairs, (B) emasculated flowers showing nectaries, ovary and stigma. Scale bars = 1 mm

Figure 25. Mature silicle of Lepidium banksii. CHR 509034. Scale bar = 1 mm.