Simplicia felix de Lange, J.R.Rolfe, Smissen & Ogle, 2016

de Lange, Peter J., Smissen, Rob D., Rolfe, Jeremy R. & Ogle, Colin C., 2016, Systematics of Simplicia Kirk (Poaceae, Agrostidinae) - an endemic, threatened New Zealand grass genus, PhytoKeys 75, pp. 119-144 : 134-138

Simplicia felix de Lange, J.R.Rolfe, Smissen & Ogle sp. nov.

Diagnosis.

Differs from Simplicia laxa by dark brown, prominently ribbed leaf sheaths; mostly glabrous, strongly ribbed mid-stem to upper-stem leaf sheaths; longer culm internodes; narrower, glabrous (sometimes with the adaxial ribs finely scabrid) leaves; shorter panicles (up to 80 mm long) with scabrid branches; minutely scabrid lemma and smaller filiform rachilla prolongation bearing cilia only at the apex.

Holotype

(Fig. 7 ). ' Eastern Wairarapa Ecological Region and District, Te Kanuka Farm Station, Kaumingi Stream’ P.J. de Lange 12167, J.R. Rolfe & T. Silbery, 27 Feb 2014, ( AK 351325 ) Isotypes. CAN, CHR, F, WAIK, WELT, US

Etymology.

The epithet ' felix ' is taken from the Latin for ' lucky ' (N.G. Walsh, MEL pers comm., 14 January 2016) as in ' lucky find ' in reference to the circumstances of this species’ discovery; that came about through the desire to get a name on an unremarkable little tuft of grass that was discovered fortuitously near Mangaweka, Central North Island by CCO on 29 January 2005 ( Ogle 2010).

Description

(Fig. 8 ). Plants forming flaccid, diffuse, often much interconnected, sprawling patches up to 1 m across. Culms 0.25-0.65 m long, green to dark brown when fresh, wiry, initially decumbent, becoming ascendant with the apices weakly erect, culm internodes 5-8, elongated, glabrous; internodes longer than subtending leaf-sheaths. Culm-nodes conspicuously swollen when fresh, dark green-brown to brown-black 0.15-0.25 mm long, rooting freely on contact with ground. Basal leaf-sheaths dull dark brown, membranous, strongly ribbed, usually abaxially pubescent (sometimes glabrous) on ribs, hairs 0.10-0.15 mm long, patent to retrorse; mid stem and upper leaf-sheaths pale-green to green, membranous, strongly ribbed, glabrous (rarely abaxially ribs finely pubescent toward sheath apex). Ligule 2.0-2.6 mm, membranous, lanceolate, apex entire, or deeply lacerate; glabrous, or with both surfaces hairy; hairs 0.15-0.18 mm long. Leaf-blade (20-)40(-60) × (1.0-)1.2-2.4(-3.0) mm, yellow-green to dark green, flat, narrow linear-lanceolate, finely ribbed, ribs smooth (sometimes minutely scabrid); margins minutely scabrid. Panicle 20-40(-80) mm long, linear to ± pyramidal, usually with basal branch or branch pair reflexed (often unevenly so); rachis glabrous (sometimes bearing a few minute prickle-teeth), branches 20-30 mm long, scabrid, binate, initially contracted but as inflorescences mature, spreading to reflexed, devoid of spikelets in lower half to two-thirds; pedicels appressed to branchlets, 0.20-0.25(0.30) mm long, finely pubescent. Spikelets 2.7-3.0 mm, 1-flowered, lanceolate, light green. Glumes pale green ( ± hyaline), glabrous, ovate-lanceolate to ovate, acute, 1-nerved, nerve sometimes extending beyond apex as a minute mucro, margins initially entire, becoming erose near apex, very sparsely ciliate in upper third; lower glume 0.5-0.6 mm, upper glume 0.75-0.8(-0.9) mm. Lemma 2.0-2.8 (-3.0) mm, light green to cream, ovate-lanceolate to lanceolate, acute, apex mucronate (mucro 0.1 mm long), 5-nerved, the inner 3 nerves conspicuous, the outer less prominent; nerves bearing evenly spaced minute (0.02-0.03 mm long), antrorse, appressed prickle-teeth, interstices usually densely (sometimes sparsely) covered with minute antrorse prickle-teeth. Palea 2.0-2.8 mm, lanceolate, green to purple-green, 1-2-nerved, nerves bearing evenly spaced minute prickle (0.02-0.03 mm long) teeth, interstices usually glabrous, sometimes sparsely covered with minute prickle-teeth. Rachilla prolongation 0.8 mm, filiform, hyaline, glabrous except for sparse cilia cresting prolongation apex. Stamens 3. Filaments 0.6-0.9 mm long, hyaline. Anthers 1.0-1.2 mm, yellow. Ovary narrowly ovoid to weakly trigonous 1.0 mm long, pale green, glabrous; styles apical, 1.0-1.2 mm, hyaline; stigmas plumose, white. Caryopsis 1.2-1.4(-1.5) mm long, laterally compressed, pale orange to orange-brown when mature. Chromosome number: 2 n = 28 ( Murray et al. 2005, P.J. de Lange 5897, AK 285424-as Simplicia laxa )

Specimens seen.

New Zealand, North Island : Rangitikei Ecological Region and District , North of Taihape , north of Paengaroa Road and east of State Highway One, Ngawaka Stream, ' Stevies Bush’, P.J. de Lange 7834 & C.C.Ogle, 29 Feb 2008, AK 304807 (Duplicates: CHR, US) ; Rangitikei Ecological Region and District , North of Taihape , south of Paengaroa Road and east of State Highway One, C.C. Ogle 4955, 17 Feb 2006, AK 295628 ; Rangitikei Ecological Region and District , North of Taihape , south of Paengaroa Road and east of State Highway One, C.C. Ogle 4954, 17 Feb 2006, AK 295627 ; Rangitikei Ecological Region and District , North of Taihape , south of Paengaroa Road and east of State Highway One, ' Campbells Bush’ P.J. de Lange 7832 & C.C. Ogle, 29 Feb 2008, AK 304805 ; Taihape , Oraukura Stream, C.C. Ogle 5625, 6 Apr 2008, AK 306012 ; Rangitikei Ecological Region and District , Taihape Scenic Reserve, Hautapu, P.J. de Lange 7833, C.C. Ogle & V. McGlynn, 28 Feb 2008, AK 304806 ; Rangitikei Ecological Region and District, Taihape Scenic Reserve, Hautapu, C.C. Ogle 4958 & V. McGlynn, 7 Mar 2006, AK 297357 ; Rangitikei Ecological Region and District , Rangitikei, Kawhatau Valley, Toetoe Road, C.C. Ogle 4893, V. McGlynn & G. La Cock, 13 Dec 2005, AK 297353 ; Rangitikei Ecological Region and District , Rangitikei , Kawhatau Valley, Toetoe Road, P.J. de Lange 7831, C.C. Ogle & V. McGlynn, 28 Feb 2008, AK 304804 ; Rangitikei Ecological Region and District , Rangitikei , Kawhatau River, Toetoe Road, ' Ben Moi’ farm, C.C. Ogle 4734, 29 Jan 2005, AK 289755 (Duplicate: CHR) ; Eastern Wairarapa Ecological Region and District , Te Kanuka Farm Station, Swamp Ridge Covenant, P.J. de Lange 12165, J.R. Rolfe & T. Silbery, 27 Feb 2014, AK 351320 (Duplicates lodged in: CHR. WELT, US) ; Eastern Wairarapa Ecological Region and District , Te Kanuka Farm Station, Upper Kaumingi Stream, P.J. de Lange 12168, J.R. Rolfe & T. Silbery, 27 Feb 2014, AK 351330 (Duplicates lodged in: CAN, WELT, US) ; Wairarapa , Ruamahanga, T. Kirk s.n., n.d., WELT SP043016 ; Ruamahanga Valley , T. Kirk s.n., 26 Jan 1880, WELT SP043022 ; Eastern Wairarapa Ecological Region and District , Admiral Road , Wainuoru River , Te Kowhai , Moetapu Bush, P.J. de Lange 12160, J.R. Rolfe & T. Silbery, 26 Feb 2014, AK 351290 (Duplicates: WELT, US) ; Eastern Wairarapa , Longbush, Tawhiriwaimanuka Stream. Ahipaku QE II Covenant, J. R. Rolfe 15017, 9 Dec 2015, AK 360429 (Duplicate: WELT) . South Island : South-East of Duntroon , Prydes Gully Road ( Ngapara , The Knolls ), B.P.J. Molloy s.n., 18 Dec 1991, CHR 616708; Duntroon Ecological District, Ngapara, The Knolls, P.J. de Lange 1340 & B.P.J. Molloy, 7 May 1992, AK 208577 (Duplicates: CHR, WAIK, WELT) . Cultivated : Ex. Cult. , Rangitikei Ecological Region and District , Rangitikei, Kawhatau Valley, Toetoe Road, P.J. de Lange 6791, 30 Nov 2006, AK 297927 ; Ex. Cult. , Rangitikei Ecological Region and District , Rangitikei, Kawhatau Valley, Toetoe Road, P.J. de Lange 6824, 23 Dec 2006, AK 298065 ; Ex. Cult. , Duntroon Ecological District, Ngapara, The Knolls, P.J. de Lange 5897, 23 Feb 2004, AK 285424 ; Ex. Cult. , Duntroon Ecological District, Ngapara, The Knolls, P.J. de Lange 6103, 3 Sep 2004, AK 288070 .

Distribution

(Fig. 1 ). Simplicia felix has so far been collected from the North and South Islands, from the current northern limit at Ngawaka Stream, near Taihape, North Island to Ngapara, North Otago, South Island. In the North Island the species has been found in two broad geographic areas, around Taihape-Mangaweka, and in the eastern Wairarapa. In the South Island, Simplicia felix is so far known only from the one location at Ngapara.

Recognition.

Genetically and morphologically Simplicia felix is more closely related to Simplicia laxa than it is to Simplicia buchananii . From Simplicia laxa it can be distinguished by the culm internodes which are longer than the subtending leaf sheaths and consistently glabrous; and by the strongly ribbed, dull dark brown basal sheaths, whose ribs are glabrous or pubescent (if pubescent then with the hairs 0.10-0.15 mm long). The mid-stem and upper-stem leaf sheaths of Simplicia felix are strongly ribbed and usually glabrous (occasionally the ribs are finely pubescent towards the sheath apex). The leaf surfaces and margins of Simplicia felix are mostly smooth though the ribs and leaf margins may be minutely scabrid. As a rule, the leaves of Simplicia felix are also shorter (up to 60 mm in Simplicia felix , 200 mm in Simplicia laxa ) and narrower than those of Simplicia laxa (1.0-3.0 mm long cf. 2.8-3.6 mm long in Simplicia laxa ). However, in cultivation the leaves of both species can get up to 4.0 mm wide. Although the inflorescences of Simplicia laxa and Simplicia felix are similar, those of Simplicia felix are smaller (up to 80 mm long rather than 150 mm long), and the branches are scabrid rather than antrorsely hairy. Although the lemma of both species overlap in range, those of Simplicia felix tend to be shorter (2.0-3.0 mm long) than those of Simplicia laxa (2.8-3.4 mm long) and minutely scabrid rather than pubescent. The rachilla prolongation of Simplicia laxa is narrowly lanceolate, 1.25-1.30 mm long and with the margins minutely ciliate, while that of Simplicia felix is filiform, 0.8 mm long and bearing sparse cilia only near the apex. Other differences are given in Table 2 .

Simplicia felix was initially confused with Simplicia buchananii (see Ogle 2010; Smissen et al. 2011) mostly because the culm internodes of both species are glabrous; they have superficially similar strongly-ribbed, often glabrous leaf-sheaths, similar smooth or finely scabrid leaves, and minutely scabrid lemma. Despite these similarities, Simplicia felix is not closely allied to Simplicia buchananii from which it is readily distinguished by the lax, sprawling, rather than erect culms; linear-pyramidal rather than linear inflorescences with binate branching, and by the lower branch or branches usually reflexed rather than appressed to the rachis. The pedicels of Simplicia felix are also pubescent rather than glabrous (rarely minutely scabrid).

Ecology.

With the exception of the Ngapara population which grows within a limestone overhang, Simplicia felix has only been collected from central and eastern North Island lowland to lower montane, often riparian, seasonally dry (drought prone), Podocarp forests overlying base-rich substrates such as limestone, calcareous mudstone and siltstone. In these areas plants have been found only in lightly shaded situations within forest remnants that have been lightly under-grazed by cattle or sheep ( Ogle 2010; de Lange et al. 2014). The reduced competition from other grasses and herbs that grazing causes, seems crucial to this species’ survival ( de Lange et al. 2014) as, in some locations where Simplicia felix had been found, portions of the same forest that had been fenced to exclude livestock did not have Simplicia ). In the Taihape-Rangitikei area, Ogle (2010) noted a close association with a range of other indigenous grasses and herbs, most notably Echinopogon ovatus , Poa imbecilla , Poa matthewsii , Cardamine debilis agg., Oxalis exilis . In the Eastern Wairarapa the same species along with Arthropodium candidum , Australina pusilla subsp. pusilla , Stellaria parviflora and the mosses Camptochaete angustata , Echinodium hispidum and Plagiomnium novae-zelandiae were key associates of Simplicia felix (P. J. de Lange unpubl. data). Further survey of similar forest remnants with ground covers dominated by these species is, we believe, likely to locate further populations.

The Ngapara site, as Simplicia laxa , was described in some detail by Johnson (1995). By comparison with the North Island sites it is anomalous and it seems likely that Simplicia persists there because the rock overhang affords some shade and protection from competing plants. Within the rock overhang Simplicia felix grows with Poa imbecilla , Poa matthewsii , Chenopodium allanii and an unnamed member of the Cardamine corymbosa complex.

Conservation status.

Simplicia felix occupies a very small area of only a few square metres wherever it occurs. It appears to have quite specific light requirements and tolerates only limited competition from other ground-cover species. The healthiest populations occur at sites where competition is reduced by grazing mammals such as cattle and sheep. This poses a quandary for conservation managers because, whilst grazing apparently benefits Simplicia felix , it will ultimately lead to the collapse of the forest canopy that provides the level of shade that is also necessary for Simplicia felix to survive. Collectively, the area of the sites where Simplicia felix occurs amounts to considerably less than 1 ha. Therefore, Simplicia felix meets the criteria to be assessed Threatened-Nationally Critical B2 using the New Zealand Threat Classification System ( Townsend et al. 2008). We also recommend that the qualifiers Data Poor ( ‘DP’) and Range Restricted ( ‘RR’) be appended to the assessment- ‘DP’ because there are no population trend data available and because several areas of possibly suitable habitat in the Rangitikei and Eastern Wairarapa have not been surveyed for the presence of Simplicia felix ; ‘RR’ because its habitat requirements are apparently very narrow.

Figures

Figure 1. Distribution of Simplicia species and showing locations discussed in text.

Figure 7. Holotype of Simplicia felix de Lange, J. R. Rolfe, Smissen & Ogle.

Figure 8. Simplicia felix. A habitat, Te Kanuka Farm Station, Upper Kaumingi Stream east Wairarapa, North Island, New Zealand B growth habit and inflorescence C culm, leaf base, sheath and ligule D spikelet showing reduced glumes and lemma (images: J. R. Rolfe)