Dicksonia perriei Noben & Lehnert, 2013

Noben, Sarah & Lehnert, Marcus, 2013, The genus Dicksonia (Dicksoniaceae) in the western Pacific, Phytotaxa 155 (1), pp. 23-34 : 31-32

Dicksonia perriei Noben & Lehnert , sp. nov. ( Figs. 2B , 3B )

Type:— NEW CALEDONIA. Province du Nord: Mont Colnett, 20°30'S, 164°42'E, 1050 m, 29 October 2004, U. G . Swenson, G . McPherson & A . Mouly 605 (holotype MO, isotype S) .

The new species Dicksonia perriei is most similar to D. thyrsopteroides , especially in laminar characters but differs in characters of the petiole (uniform layer of matted yellowish to orange brown, wooly ciliate hairs in D. perriei vs. spreading reddish brown setiform hairs and a sooty undercoat in D. thyrsopteroides ).

Trunks to 2 m tall, to 20 cm diameter with persistent petiole bases (reports of diameters to 50 cm probably include adventitious root mantle); adventitious buds apparently present, sprouting close to the soil and leading to close groups of 2–3 trunks. Fronds to 400 cm long, ascending, dimorphic, usually fertile in lower half but can be wholly fertile. Petiole ca. 100 cm long, to 5 cm wide, remaining green for a long time on the plant, only turning brown when dead and dried, smooth to slightly rough, covered with easily abraded, short (ca. 7 mm) pale, yellowish to orange brown, wooly hairs. Laminae at least to 200 × 130 cm, tripinnate-pinnatifid, firm herbaceous, gradually reduced apically, widest at the middle. Leaf axes [rachises, costae and costules] of young fronds densely covered many orange to reddish brown catenate hairs on both sides, caduceus, abaxially mostly persisting the axils of pinnae and pinnules, adaxially hairs fewer and paler but more persistent. Veins slightly to strongly hairy; hairs whitish to reddish. Pinnae subsessile to sessile, oblong-lanceolate with attenuate tips, 12–14 pairs per frond. Sterile pinnae to 65 × 25 cm; fertile pinnae to 33 × 16 cm. Sterile pinnules to 12–13 × 2.2 cm, oblong-lanceolate, basally auriculate. Fertile pinnules to 9 × 1.6 cm, oblong, sessile. Fertile segments sessile, the laminar tissue reduced to thin strands along the veins, but intermediary segments with more laminar tissue may occur. Sterile segments weakly lobed or dissected, margins serrate, sessile. Sori 1.7–1.8 mm wide, oblong to slightly kidney shaped when closed, circular when open, at the end of unbranched lateral veins. Spores not examined.

Distribution and habitat: —Primarily northern New Caledonia, rare in the centre and absent from the south, in evergreen mountain rainforest at (750–) 1050–1460 m, avoiding ultramafic soils ( Fig. 1B, D ).

Etymology: —The epithet honours our colleague Leon Perrie (Museum of New Zealand, Te Papa Tongarewa), who first pointed out the distinctness of this species and who provided crucial information for the description of this species.

Paratype: — NEW CALEDONIA. Province du Nord: Mont Colnett, 20°30'S, 164°42'E, 1400 m, 31 October 2004, U. G . Swenson et al. 620 (MO, S).

Additional specimens (digitalized): — NEW CALEDONIA. Province du Nord: Sud de Canala , [ca. 21°31'10''S, 165°57'11'' E,] ca. 900 m, 20 February 1869, Balansa 1596 ( P); Forêt Plate, E towards Mont Katépouenda, 21°08–09' S , 165°07–08'E, 750 m, 14 August 1965, Bernardi 10192 ( NOU n.v., P); Mont Panie , 20°35'58''S, 164°45'32''E, 1280 m, 9 October 2012, L . Perrie NC2012-182 ( NOU n.v., WELT), 20°35'23''S, 164°45'43''E, 1460 m, 9 October 2012, L . Perrie NC2012-184 ( NOU n.v., WELT); Dôme de l’Ignambi , [ca. 20°27'46"S, 164°36'10"E,] 1300 m, 19 August 1965, M . Schmid 548 ( P) .

Discussion:— Dicksonia perriei was previously treated as D. thyrsopteroides because of shared morphological characters of the lamina (e.g. the sessile pinnae and the strong reduction of fertile segments). However, D. perriei differs in the characteristics of the petiole, which is smooth to slightly rough with yellowish to orange, wooly, ciliate hairs (vs. pale to reddish brown, setiform hairs in D. thyrsopteroides ) and the lack of a sooty undercoat (vs. present). In addition, D perriei has thicker petioles than D. thyrsopteroides (to ca. 2 cm wide vs. more than 3 cm wide in fresh material) and is a more massive plant that usually grows in small groups of 2–3 thick and relatively short trunks (to 20 cm diameter vs. usually with solitary, relatively slender trunks to 10 cm diameter). Herbarium specimens of D. perriei are conspicuous due to the large size of the pinnae and pinnules.

We have seen photographs of Dicksonia perriei on Mont Panié, where the species is dominant tree fern in the upper parts (L. Perrie, personal communication). The range of this species is insufficiently known, but it seems to be restricted to higher elevations in the northern province, outside of the ultramafic outcrops ( Pintaud et al. 2001) and above the elevational range of D. thyrsopteroides . Outliers that were collected farther south are Balansa 1596 from 900 m and Bernardi 10192 from 750 m (see Discussion).

Figures

FIGURE 1. Distribution of Dicksonia species on New Caledonia related to precipitation and geology: A. Precipitation; 1500 mm/a isohyet delimits rain forest vegetation, 3000 mm/a isohyet delimit centers of endemism (fide Pintaud et al. 2001); basemap modified from commons.wikimedia.org. B. Geology (© http://runswithrocks.wordpress.com). C. Dicksonia baudouinii. D. Dicksonia perriei, sp. nov. E. Dicksonia munzingeri, sp. nov. F. Dicksonia thyrsopteroides. (Basemap © d-maps.com)

FIGURE 2. Morphological features of New Caledonian Dicksonia species: First row (1) sterile (A, C & D) or intermediate segments (B), abaxially; second row (2) fertile segments, adaxially; third row (3) petioles. A. Dicksonia baudouinii. B. Dicksonia perriei, sp. nov. C. Dicksonia munzingeri, sp. nov. D. Dicksonia thyrsopteroides.

FIGURE 3. Morphological features of New Caledonian Dicksonia species: sterile pinnules, adaxially A. Dicksonia baudouinii. B. Dicksonia perriei, sp. nov. C. Dicksonia munzingeri, sp. nov. D. Dicksonia thyrsopteroides.