Pollen morphology and its taxonomic utility in the Southern Hemisphere bracteate-prostrate forget-me-nots (Myosotis, Boraginaceae)

Figures & data

Figure 1. Scanning electron microscope (SEM) images of Southern Hemisphere bracteate-prostrate Myosotis pollen showing different pollen types, features and terminology in equatorial view (A–G) and polar view (H–I). A, Myosotis discolor type pollen of M. brevis (WELT SP090543/A) with distinctive lack of granula on most of exine (psilate; white arrow) and alternating colpori (c) and pseudocolpi (pc); B, Myosotis angustata type pollen of M. glabrescens (WELT SP044913) with distinctive oblong (rectangular) shape; C, Myosotis australis type pollen of M. sp. “Volcanic Plateau” (CHR 310610) with wide and psilate pseudocolpus (white arrow); D, close up of M. brevis (WELT SP090550/A) pollen with granulate endoaperture (en) and ektoaperture (ek) membranes of the colporus (c), and psilate membrane of the pseudocolpus (pc), as well as granulate aperture margins (white arrows); E, Myosotis australis type pollen of M. lyallii (CHR 207153) with partially anastomosing pseudocolpi (pc; white arrow); F, Myosotis uniflora type pollen of M. matthewsii (AK 46608) with distinctive polar cap (p cap); G, close up of M. colensoi × M australis (WELT SP090554) colporus with granula (g) on exine and ektoaperture (ek) membrane, and verruca (v) on endoaperture (en) membrane; H, Myosotis australis type pollen of M. glauca (CHR 191750) in polar view, which lacks a polar cap (white arrow); I, Myosotis uniflora type pollen of M. pulvinaris (OTA 031024) in polar view, with fully anastomosing pseudocolpi (pc; white arrow) forming a distinctive polar cap (p cap). pc, pseudocolpus; c, colporus (a compound aperture comprised of ektoaperture [ek] and endoaperture [en]); p cap, polar cap; v, verruca; g, graunula. Scale bar = 5 μm.

Table 1. Voucher information for all 78 Myosotis specimens sampled in this study.

Species or tag name	nMDS cluster (Figure 5)^a	Figure with SEM image of pollen	Herbarium accession no.	Collector	Date collected	Locality
M. albiflora	1	2P	CONC 73040	Pisano 6096	16/12/1985	CHILE, Fiordo Peel, río al E del cerro Aguilera
M. albiflora	1	2O	S15–37506	Borge 178	18/03/1899	CHILE, Patagonia austral, Mayer
M. albiflora	(2)	n/a	S15–37500	Santesson 1597	11/01/1941	CHILE, Río Rubens, near Hotel Río Rubens (about 50 km SE of Natales)
M. antarctica	(1)	2A	WELT SP102775	Prebble JMP13063	27/12/2013	Campbell Island, between Menhir and Mt Dumas
M. antarctica	1	n/a	WELT SP102777	Prebble JMP13065	27/12/2013	Campbell Island, Mt Azimuth
M. antarctica	1	2B	WELT SP102779	Prebble JMP13067	28/12/2013	Campbell Island, Mt Honey
M. brevis	1	1A	WELT SP090543/A	Meudt et al. HMM311A	05/10/2011	NI, Taranaki, Stent Rd
M. brevis	1	1D, 2Q	WELT SP090550/A	Meudt et al. HMM318	07/11/2011	NI, Wellington Region, Ohau Bay
M. brevis	1	2R	WELT SP102761	Prebble JMP13045	08/10/2013	SI, Otago, Bannockburn
M. chaffeyorum	3	4I–J	CHR 310255	Druce s.n.	12/1976	SI, cult. Pinehaven, ex NW Nelson, Canaan, Pikikeruna Range
M. chaffeyorum †	n/a	n/a	CHR 311720	Druce s.n.	02/1977	SI, NW Nelson, Takaka
M. cheesemanii	3	4B	OTA 62709	Mark & Dickinson s.n.	18/12/1992	SI, Otago, N Dunstan Mountains
M. cheesemanii	3	4A	CHR 475919	Druce APD1655	01/1992	SI, Otago, Pisa Range
M. colensoi	2	3B	CHR 96401	Mason 4460	27/10/1956	SI, Canterbury, Broken River
M. colensoi	2	3A	WELT SP095578	Burke s.n.	11/12/1963	SI, Canterbury, Castle Hill Reserve
M. colensoi	2	n/a	CHR 363546	Druce s.n.	01/1980	SI, Marlborough, Chalk Range
M. colensoi  × M. australis hybrid	2	1G	WELT SP090554	Meudt et al. HMM322A	24/11/2011	SI, Marlborough, Chalk Range
M. drucei †	n/a	n/a	WELT SP100445	Prebble JMP12017(2)	23/12/2012	NI, Ruahines, Maungamahue
M. drucei	1	2D	WELT SP102783	Prebble JMP14002	02/02/2014	SI, Central Otago, Rock and Pillar
M. drucei	(1)	2C	CHR 386879	Molloy	02/1981	SI, Tapuae-o-Uenuku
M. elderi	2	3E	CHR 132818	Druce s.n.	01/01/1965	NI, Park Valley cirque, Tararua Range
M. elderi	2	n/a	CHR 295326	Wall s.n.	01/12/1921	SI, Canterbury, Mt Potts
M. elderi	2	3F	OTA 031559	Mark s.n.	31/12/1970	SI, Fiordland, Lake Wapiti, Upper Doon Valley
M. elderi	2	n/a	WELT SP103837	Meudt HMM382O	17/12/2014	SI, Marlborough, Mt St Patrick
M. glabrescens †	n/a	n/a	WELT SP089801	Thorsen 012/07	30/01/2007	SI, Hector Mountains
M. glabrescens	1	1B, 2S–T	WELT SP044913	Cockayne s.n.		SI, Otago, Old Man Range
M. glauca	1	2F	WELT SP100497	Prebble JMP13039	01/03/2013	SI, Otago, Macraes
M. glauca †	n/a	n/a	WELT SP093285	Prebble JMP12004a	15/02/2012	SI, Otago, Nevis Valley
M. glauca	(2)	1H, 2E	CHR 191750	Moore s.n.	26/04/1969	SI, Otago, Tourist spur on Mt Ida
M. aff. glauca	(2)	3S	WELT SP093282	Prebble JMP12002	14/02/2012	SI, Otago, Pisa Range
M. aff. glauca	(2)	3T	WELT SP089898	Thorsen s.n.	23/01/2006	SI, Otago, Pisa Range, around snow farm
M. aff. glauca	(1)	n/a	CHR 586018	Thorsen s.n.	26/01/2006	SI, Otago, Western Pisa Range
M. lyallii var. lyallii	2	1E, 3G	CHR 207153	Anderson s.n.	01/01/1971	SI, Fiordland, Wapiti Lake
M. lyallii var. lyallii	2	3H	WELT SP039638	Oliver s.n.	22/01/1951	SI, Westland, Mt Moltke
M. lyallii var. townsonii (Cheeseman) L.B.Moore	2	3I	WELT SP104488/A	Meudt & Kusabs HMM422A	16/02/2016	SI, Doubtful Range, above Lake Man
M. lyallii var. townsonii	2	3J	WELT SP091837	Sneddon s.n.	12/03/1983	SI, NW Nelson, Mt Kendall
M. matthewsii	3	n/a	CHR 469691	Druce APD716	05/1989	NI, cult. Hutt Valley ex Warawara Forest, North Auckland
M. matthewsii	3	1F, 4L	AK 46608	Matthews s.n.	17/11/1898	NI, Northland, Mauteringi, Kaitaia
M. matthewsii	3	4K	WELT SP002571	Matthews s.n.	12/1898	NI, Northland, Near Kaitaia
M. pulvinaris	3	4E	WELT SP103819	Meudt et al. HMM365A	11/12/2014	SI, Dunstan Mountains
M. pulvinaris	3	4F	WELT SP089842	Thorsen s.n.	06/12/2006	SI, Kakanui Mountains, Mount Nobbler
M. pulvinaris	3	1I	OTA 031024	Mark s.n.	22/11/1970	SI, Otago, Garvie Mountains
M. aff. pulvinaris	3	4H	CHR 624106	Druce s.n.	01/1994	SI, Otago, Dunstan
M. aff. pulvinaris	3	4G	WELT SP002699	Speden s.n.	11/1923	?
M. aff. pulvinaris	3	n/a	WELT SP104546	Garnock-Jones & Rance PGJ3156	10/01/2016	SI, Fiordland National Park, Mt Burns, on ridge 1 km SSW of main summit
M. pulvinaris †	n/a	n/a	WELT SP089800	Thorsen s.n.	01/02/2007	SI, Otago, Hector Mountains, Sproules Creek headbasin.
M. pygmaea	1	2G	CHR 245912	Druce s.n.	11/1971	NI, Egmont coast Puketapu Road end
M. pygmaea	1	n/a	WELT SP100460	Prebble JMP13022	26/01/2013	SI, NW Nelson, Sandhill Creek
M. pygmaea	1	2H	AK 231694	de Lange s.n.	08/01/1995	SI, Southland, Waituna
M. sp. “Fiordland”	2	3K–L	CHR 338108	Given et al. 8873	21/03/1977	SI, Fiordland, Mt George
M. sp. “Fiordland”†	n/a	n/a	CHR 207155	Anderson s.n.	01/01/1971	SI, Fiordland, Wapiti Lake
M. sp. “intermedia”	(2)	3Q	WELT SP089911	Thorsen s.n.	31/12/2005	SI, Otago, Rock and Pillar
M. sp. “intermedia”	1	n/a	WELT SP089916	Thorsen 129/09	15/12/2009	SI, Otago, Taieri River, Beaumont Station
M. sp. “intermedia”	2	3R	WELT SP089909	Thorsen s.n.	05/12/2005	SI, Otago, The Remarkables, Glen Roy Station
M. sp. “Rock and Pillar”	2	n/a	WELT SP089905	Thorsen s.n.	31/12/2005	SI, Otago, Rock and Pillar
M. sp. “Rock and Pillar”†	n/a	n/a	WELT SP089904	Thorsen s.n.	01/01/2006	SI, Otago, Rock and Pillar
M. sp. “Rock and Pillar”	2	3D	WELT SP089763/A	Thorsen 150/09	16/12/2009	SI, Otago, Taieri River, Beaumont Station
M. sp. ”Rock and Pillar”	2	3C	OTA 002703	Baylis s.n.	24/02/1952	SI, Otago, Rock and Pillar Range
M. sp. “ serpentine”	2	3M–N	CHR 320240	Johnson s.n.	01/12/1978	SI, Southland, Black Ridge near Mossburn
M. sp. “Tapuae-o-Uenuku”	2	n/a	WELT SP100449	Prebble JMP13003	06/01/2013	SI, Marlborough, Tapuae-o-Uenuku
M. sp. “Tapuae-o-Uenuku”	2	3O	CHR 386966	Molloy s.n.	01/02/1981	SI, Marlborough, Tapuae-o-Uenuku
M. sp. “Tapuae-o-Uenuku”	2	3P	CHR 386966	Molloy s.n.	01/02/1981	SI, Marlborough, Tapuae-o-Uenuku
M. sp. “Volcanic Plateau”	1	1C, 2J	CHR 310610	Druce s.n.	01/01/1977	NI, Ruahine Ranges, Makirikiri tarns
M. sp. “Volcanic Plateau”	1	2I	WELT SP089738	Singers s.n.	15/02/2011	NI, Volcanic Plateau
M. sp. (unknown)	1	2M–N	WELT SP103892	Rogers s.n.	13/10/2014	SI, Otago, Clutha River
M. spathulata var. radicata L.B.Moore†	n/a	n/a	CHR 260350	Druce s.n.	12/1973	NI, NW Ruahine Range, Te Rakaunuiakura
M. spathulata var. radicata	3	4M–N	AK 174020	Wright 7396	30/12/1985	NI, Whakatake, Motuhora (Whale) Island
M. spathulata var. spathulata	3	4P	AK 303980	de Lange & Baird CH1938	30/11/2008	Chatham Islands, Rekohu (Chatham Island), Southern Tablelands, Alfred Preece’s Land, Te Mangahou Creek
M. spathulata var. spathulata	3	4O	CHR 210782	Druce s.n.	12/1970	NI, E Wairarapa, Mt Percy
M. tenericaulis	3	4Q–R	WELT SP095613	Burke s.n.	05/01/1982	SI, Marlborough, Boulder Creek
M. tenericaulis	(2)	4S	WELT SP002691	Petrie s.n.	?	SI, Otago, Inch Clutha (near Romahapa)
M. tenericaulis	1	4T	WELT SP089834/A	Thorsen 012/10	16/02/2010	Stewart Island, Mt Allen, Rakeakua River
M. aff. tenericaulis	(1)	n/a	WELT SP104478	Meudt & Kusabs HMM411A	11/01/2016	SI, Otago, Garvie Mountains, east of Lake Laura
M. aff. tenericaulis	1	2L	CHR 439290	Johnson 682	19/11/1987	SI, Otago, North of Lammerlaw Range, Red Swamp
M. aff. tenericaulis	1	2K	WELT SP103811	Meudt et al. HMM357A	09/12/2014	SI, Otago, Old Man Range
M. uniflora †	n/a	n/a	CHR 514207	Heenan s.n.	?	SI, Canterbury, Ashburton River, above Hakatere
M. uniflora	3	n/a	CHR 467435A	Douglass 90/26	21/10/1990	SI, Canterbury, Waimakariri River
M. uniflora	3	4C–D	CHR 499326	Johnson 1260	08/12/1994	SI, Otago, Huxley Valley below Monument Hut

Notes: All specimens were originally collected from New Zealand except for those of M. albiflora from Chile; SI, South Island; NI, North Island; herbarium acronyms follow Index Herbariorum (Thiers, continuously updated). A dagger (†) highlights the nine samples which were attempted but did not produce sufficient high quality pollen for SEM imaging.

^anMDS clusters in parentheses are Mclust placements with uncertainty scores > 0.1 (Figure 5).

Table 2. Summary of the nine quantitative and qualitative pollen morphological characters analysed in the nMDS and Mclust analyses from the Myosotis bracteate-prostrate group taxonomic entities.

Species, variety or tag-name	n^a	nMDS cluster (Figure 5)^b	Polar cap presence^c	Total no. apertures^d	Pollen type^e	Polar axis length, P (μm)	Pseudocolpus width (μm)	Colporus ektoaperture length (μm)	Colporus ektoaperture width (μm)	Colporus endoaperture length (μm)	P :E ratio	Colporus endoaperture length:width ratio^6	Notes
M. glabrescens	1	1	0	8	angustata	11.8	0.4	5.5	2.3	1.6	1.4	1.1	Oblong (rectangular) with flat poles in equatorial view (some nearly hourglass-shaped), completely spheroidal in polar view, pseudocolpi psilate?
M. brevis	3	1	0	8	discolor	11.6–12.4 (12.0 ± 0.5)	1.0–1.3 (1.2 ± 0.2)	5.7–6.8 (6.4 ± 0.6)	2.8–3.0 (2.9 ± 0.2)	1.8–2.2 (2.0 ± 0.3)	1.4–1.4 (1.4 ± 0.1)	0.8–1.2 (1.0 ± 0.2)	Annual ; Psilate with granula densely distributed on aperture margins only, as well as on ektoaperture and endoaperture membranes, pseudocolpi wide with largely psilate membranes, and one pair longer than the other pair
M. antarctica	3	1, (1)	0	8	australis	11.9–13.2 (12.6 ± 0.7)	0.5–0.6 (0.6 ± 0.1)	4.9–7.5 (5.8 ± 1.5)	2.8–3.2 (3.1 ± 0.3)	2.3–3.0 (2.6 ± 0.4)	1.1–1.2 (1.1 ± 0.1)	0.9–1.0 (1.0 ± 0.1)	Campbell Island ; some pseudocolpi merging but not forming polar cap, ektoapertures sometimes not well defined
M. drucei	2	1, (1)	0	8	australis	11.0–12.1 (11.6 ± 0.8)	0.6–0.7 (0.7 ± 0.1)	6.2–7.2 (6.7 ± 0.8)	2.9–3.1 (3.0 ± 0.2)	2.3–2.9 (2.6 ± 0.5)	1.1–1.1 (1.1 ± 0.1)	0.9–1.1 (1.0 ± 0.2)
M. pygmaea	3	1	0	8	australis	12.3–12.9 (12.6 ± 0.3)	0.5–0.8 (0.7 ± 0.2)	4.4–5.8 (5.1 ± 0.8)	2.4–3.0 (2.6 ± 0.4)	2.1–2.9 (2.6 ± 0.4)	1.2–1.3 (1.3 ± 0.1)	1.0–1.4 (1.1 ± 0.2)	Ektoaperture sometimes not well defined, pseudocolpi sometimes wide and nearly psilate
M. aff. tenericaulis	3	1, (1)	0	8	australis	11.6–13.6 (12.7 ± 1.1)	0.5–0.7 (0.6 ± 0.2)	6.0–7.1 (6.4 ± 0.7)	3.0–3.3 (3.2 ± 0.2)	2.1–2.7 (2.5 ± 0.4)	1.2–1.3 (1.3 ± 0.1)	0.7–1.2 (1.0 ± 0.3)	Ektoaperture sometimes not well defined, endoaperture sometimes spheroidal/bulgy
M. sp. (unknown)	1	1	0	8	australis	11.2	1.2	4.5	2.4	2.7	1.0	1.2	Ektoaperture sometimes not well defined, pseudocolpi wide
M. glauca	2	1, (2)	0	8 or 10	australis	10.6–12.7 (11.6 ± 1.5)	0.4–0.6 (0.5 ± 0.2)	6.0–7.1 (6.5 ± 0.8)	2.7–3.3 (3.0 ± 0.5)	2.8–3.2 (3.0 ± 0.3)	1.0–1.2 (1.1 ± 0.2)	1.1–1.2 (1.1 ± 0.2)
M. aff. glauca	3	(2), (1)	0	8 or 10	australis	11.1–12.4 (11.9 ± 0.8)	0.4–0.6 (0.5 ± 0.1)	4.7–6.5 (5.8 ± 1.0)	2.9–3.6 (3.3 ± 0.4)	2.8–3.3 (3.0 ± 0.3)	1.0–1.1 (1.1 ± 0.1)	1.0–1.1 (1.0 ± 0.1)
M. sp. “intermedia”	3	1, 2, (2)	0	8 or 10	australis	12.7–13.3 (12.9 ± 0.3)	0.4–0.5 (0.5 ± 0.1)	5.2–6.4 (5.8 ± 0.7)	2.7–4.0 (3.2 ± 0.7)	2.3–3.5 (2.7 ± 0.7)	1.1–1.3 (1.1 ± 0.2)	1.0–1.1 (1.0 ± 0.1)
M. sp. “Volcanic Plateau”	2	1	0	8 or 10	australis	12.1–12.3 (12.2 ± 0.2)	1.1–1.2 (1.2 ± 0.2)	6.0–6.7 (6.3 ± 0.6)	3.0–3.4 (3.2 ± 0.3)	3.1–3.2 (3.1 ± 0.2)	1.1–1.2 (1.2 ± 0.1)	1.1–1.2 (1.1 ± 0.1)	Pseudocolpi wide and nearly psilate
M. sp. “Tapuae-o-Uenuku”	3	2	0	8 or 10	australis	13.4–14.1 (13.7 ± 0.4)	0.7–0.8 (0.8 ± 0.1)	7.0–8.3 (7.6 ± 0.7)	3.5–3.6 (3.5 ± 0.1)	3.2–3.6 (3.4 ± 0.3)	1.1–1.2 (1.1 ± 0.1)	1.0–1.2 (1.1 ± 0.2)
M. albiflora	3	1, (2)	0	8 or 10	australis	12.1–12.5 (12.3 ± 0.2)	0.4–0.8 (0.6 ± 0.3)	4.7–5.3 (5.1 ± 0.4)	2.6–2.9 (2.7 ± 0.2)	2.1–3 (2.6 ± 0.5)	1.0–1.2 (1.1 ± 0.2)	1.0–1.5 (1.3 ± 0.3)	Southern Chile ; ektoaperture and sometimes endoaperture not well defined
M. colensoi	3	2	0	10	australis	14.8–15.7 (15.3 ± 0.6)	0.3–0.6 (0.5 ± 0.2)	8.5–9.3 (8.8 ± 0.5)	3.3–3.8 (3.6 ± 0.3)	2.5–3.6 (3.0 ± 0.6)	1.1–1.2 (1.2 ± 0.1)	1.0–1.2 (1.1 ± 0.1)
M. elderi	4	2	0	10	australis	13.7–16.5 (14.6 ± 1.3)	0.3–0.9 (0.6 ± 0.3)	7.0–8.4 (7.6 ± 0.6)	3.1–4.0 (3.7 ± 0.5)	2.8–3.7 (3.2 ± 0.5)	1.1–1.3 (1.1 ± 0.1)	0.9–1.3 (1.1 ± 0.2)
M. lyallii var. lyallii	2	2	0	10	australis	14.6–15.5 (15.1 ± 0.7)	0.4–0.4 (0.4 ± 0.1)	7.4–8.5 (7.9 ± 0.8)	3.5–4.0 (3.7 ± 0.4)	2.7–3.7 (3.2 ± 0.7)	1.1–1.2 (1.1 ± 0.1)	1.0–1.1 (1.1 ± 0.1)
M. lyallii var. townsonii	2	2	0	10	australis	15.0–15.0 (15.0 ± 0.1)	0.4–0.7 (0.6 ± 0.2)	6.9–7.3 (7.1 ± 0.3)	2.4–3.2 (2.8 ± 0.6)	2.6–3.4 (3.0 ± 0.6)	1.1–1.3 (1.2 ± 0.2)	1.0–2.2 (1.6 ± 0.9)
M. lyallii (both varieties)	4	2	0	10	australis	14.6–15.5 (15.0 ± 0.4)	0.4–0.7 (0.5 ± 0.2)	6.9–8.5 (7.5 ± 0.7)	2.4–4 (3.3 ± 0.7)	2.6–3.7 (3.1 ± 0.6)	1.1–1.3 (1.2 ± 0.2)	1.0–2.2 (1.3 ± 0.6)
M. sp. “Fiordland”	1	2	0	10	australis	13.4	0.5	6.8	3.0	2.8	1.1	0.9
M. sp. “serpentine”	1	2	0	10	australis	13.5	0.5	6.2	3.4	3.2	1.0	1.1
M. colensoi x. M. australis	1	2	0	10 or 12	australis	14.7	0.4	8.0	3.7	3.5	1.0	1.1
M. sp. “Rock and Pillar”	3	2	0	8, 10 or 12	australis	12.1–14.1 (13.4 ± 1.2)	0.6–0.6 (0.6 ± 0.1)	6.4–7.4 (7.0 ± 0.6)	3.4–3.8 (3.5 ± 0.3)	2.9–4.2 (3.5 ± 0.7)	1.0–1.1 (1.1 ± 0.1)	1.0–1.4 (1.2 ± 0.2)	Endoaperture sometimes spheroidal/bulgy
M. tenericaulis	3	1, (2), 3	0 or 1	10	australis (2) or uniflora (1)	11.6–11.9 (11.8 ± 0.2)	0.3–0.8 (0.6 ± 0.3)	5.4–8.9 (6.6 ± 2)	2.6–3.4 (2.9 ± 0.4)	2.6–3.7 (3.0 ± 0.6)	1.0–1.1 (1.1 ± 0.1)	1.2–1.3 (1.2 ± 0.1)	Endoaperture and/or ektoaperture sometimes not well defined, pseudocolpi sometimes very wide
M. aff. pulvinaris	3	3, 2	0 or 1	8, 10 or 12	australis (1) or uniflora (2)	13.2–13.8 (13.6 ± 0.4)	0.4–0.4 (0.4 ± 0.1)	7–10.3 (8.6 ± 1.7)	3–3.7 (3.4 ± 0.4)	2.9–3.9 (3.4 ± 0.5)	1.0–1.1 (1.1 ± 0.1)	1.1–1.4 (1.2 ± 0.2)
M. matthewsii	3	3	1	8 or 10	uniflora	13.1–14.7 (14.1 ± 0.9)	0.2–0.4 (0.3 ± 0.2)	6.4–6.8 (6.7 ± 0.2)	2.8–3.6 (3.3 ± 0.5)	2.9–3.5 (3.3 ± 0.3)	1.0–1.2 (1.1 ± 0.1)	1.2–1.4 (1.3 ± 0.2)	Ektoaperture and/or endoaperture sometimes not well defined
M. spathulata var. spathulata	2	3	1	8 or 10	uniflora	12.1–12.2 (12.1 ± 0.1)	0.4–0.5 (0.4 ± 0.2)	5.2–5.3 (5.2 ± 0.1)	3.0–3.4 (3.2 ± 0.4)	2.7–3.4 (3.1 ± 0.5)	1.0–1.0 (1.0 ± 0.1)	1.2–1.3 (1.2 ± 0.1)	Ektoaperture sometimes not well defined
M. spathulata var. radicata	1	3	1	10	uniflora	12.7	0.4	4.8	2.1	1.9	1.0	1.2	Endoaperture not well defined
M. spathulata (both varieties)	3	3	1	8 or 10	uniflora	12.1–12.7 (12.3 ± 0.4)	0.4–0.5 (0.4 ± 0.1)	4.9–5.3 (5.1 ± 0.3)	2.2–3.4 (2.9 ± 0.7)	2.0–3.4 (2.7 ± 0.8)	1.0–1.1 (1.0 ± 0.1)	1.2–1.3 (1.2 ± 0.1)	Endoaperture and/or ektoaperture sometimes not well defined
M. chaffeyorum	1	3	1	10 or 12	uniflora	12.6	0.4	5.7	3.5	3.5	1.0	1.1	Endoaperture not well defined
M. cheesemanii	2	3	1	10 or 12	uniflora	14.4–14.4 (14.4 ± 0.1)	0.3–0.5 (0.4 ± 0.2)	5.7–7.3 (6.5 ± 1.2)	2.8–3.3 (3.1 ± 0.4)	3.6–3.8 (3.7 ± 0.2)	1.0–1.1 (1.1 ± 0.1)	1.3–2.0 (1.6 ± 0.5)	Ektoaperture sometimes not well defined
M. pulvinaris	3	3	1	10 or 12	uniflora	13.2–13.9 (13.6 ± 0.4)	0.3–0.7 (0.5 ± 0.3)	6.2–6.7 (6.5 ± 0.3)	3.1–4.4 (3.9 ± 0.7)	3.7–4.5 (4.1 ± 0.4)	1.0–1.0 (1.0 ± 0.1)	1.1–1.5 (1.3 ± 0.3)	Ektoaperture and/or endoaperture sometimes not well defined, endoaperture sometimes spheroidal/bulgy
M. uniflora	2	3	1	10 or 12	uniflora	12.8–13.2 (13.0 ± 0.3)	0.4–0.6 (0.5 ± 0.2)	5.2–7.3 (6.3 ± 1.5)	3.3–5.3 (4.3 ± 1.5)	3.2–3.4 (3.3 ± 0.1)	1.0–1.0 (1.0 ± 0.1)	1.2–1.3 (1.3 ± 0.1)	Endoaperture sometimes not well defined
SUMMARY	1–4	1–3	0 or 1	8, 10 or 12	discolor, angustata, australis or uniflora	10.6–16.5  (13.1 ± 1.3)	0.2–1.3  (0.6 ± 0.3)	4.4–10.3  (6.6 ± 1.3)	2.2–5.3  (3.2 ± 0.6)	1.7–4.5  (3.0 ± 0.6)	1.0–1.5  (1.1 ± 0.2)	0.7–2.2  (1.2 ± 0.3)

Note: The table is ordered first by polar cap presence/pollen type, then by total number of apertures and, finally, by species name.

^an = number of specimens sampled.

^bnMDS clusters in parentheses are placements with Mclust uncertainty scores > 0.1 (Figure 5).

^cPolar cap presence = 1, absence = 0.

^dTotal no. apertures = number of colpori + pseudocolpi.

^ePollen type follows Moar (1993) and Grau & Leins (1968). For each of the eight measurements and six ratios, maximum and minimum (mean ± standard deviation) are given when n > 1.

Figure 2. Scanning electron microscope (SEM) images of Southern Hemisphere bracteate-prostrate Myosotis pollen from nMDS Cluster 1 (Figure 5) in equatorial view (A, C, E, G, I, K, M, O, Q, S), polar view (B, D, F, H, J, L, P, R, T) or close up of endoaperture (N) showing Myosotis australis type (A–P), M. discolor type (Q–R) and M. angustata type pollen (S–T). A–B, Myosotis antarctica (WELT SP102775, WELT SP102779, respectively); C–D, M. drucei (CHR 386879, WELT SP102783); E–F, M. glauca (CHR 191750, WELT SP100497); G–H, M. pygmaea (CHR 245912, AK 231694); I–J, M. sp. “Volcanic Plateau” (WELT SP089738, CHR 310610); K–L, M. aff. tenericaulis (WELT SP103811, CHR 439290); M–N, M. sp. (unknown) (both WELT SP103892); O–P, M. albiflora (S15-37506, CONC 73040); Q–R, M. brevis (WELT SP090550/A, WELT SP102761); S–T, M. glabrescens (both WELT SP044913). Scale bar = 5 μm. These and additional pollen images are available on Te Papa’s Collections Online (http://collections.tepapa.govt.nz/Topic/10487).

Figure 3. Scanning electron microscope (SEM) images of Southern Hemisphere bracteate-prostrate Myosotis pollen from nMDS Cluster 2 (Figure 5) in equatorial view (A, C, E, G, I, K, M, O, Q, S) or polar view (B, D, F, H, J, L, N, P, R, T) showing Myosotis australis type pollen (A–T). A–B, Myosotis colensoi (WELT SP095578, CHR 96401, respectively); C–D, M. sp. “Rock and Pillar” (OTA 002703, WELT SP089763/A); E–F, M. elderi (CHR 132818, OTA 031559); G–H, M. lyallii var. lyallii (CHR 207153, WELT SP039638); I–J, M. lyallii var. townsonii (WELT SP104488/A, WELT SP091837); K–L, M. sp. “Fiordland” (both CHR 338108); M–N, M. sp. “serpentine” (both CHR 320240); O–P, M. sp. “Tapuae-o-Uenuku” (from two different plants on CHR 386966); Q–R, M. sp. “intermedia” (WELT SP089911, WELT SP089909); S–T, M. aff. glauca (WELT SP093282, WELT SP089898). Scale bar = 5 μm. These and additional pollen images are available on Te Papa’s Collections Online (http://collections.tepapa.govt.nz/Topic/10487).

Figure 4. Scanning electron microscope (SEM) images of Southern Hemisphere bracteate-prostrate Myosotis pollen from nMDS Cluster 3 (Figure 5) in equatorial view (A, C, E, G, I, K, M, O, Q, S) or polar view (B, D, F, H, J, L, N, P, R, T) showing Myosotis uniflora type pollen (A–R) and M. australis type pollen (S–T). A–B, Myosotis cheesemanii (CHR 475919, OTA 62709, respectively); C–D, M. uniflora (both CHR 499326); E–F, M. pulvinaris (WELT SP103819, WELT SP089842); G–H, M. aff. pulvinaris (WELT SP002699, CHR 624106); I–J, M. chaffeyorum (both CHR 310255); K–L, M. matthewsii (WELT SP002571, AK 46608); M–N, M. spathulata var. radicata (both AK174020); O–P, M. spathulata var. spathulata (CHR 210782, AK 303980); Q–T, M. tenericaulis (WELT SP095613 x2, WELT SP002691, WELT SP089834/A), showing high intraspecific variation with both M. uniflora (Q–R) and M. australis type pollen (S–T) represented. Scale bar = 5 μm. These and additional pollen images are available on Te Papa’s Collections Online (http://collections.tepapa.govt.nz/Topic/10487).

Figure 5. Non-metric multidimensional scaling (nMDS) analysis of a Gower’s distance matrix of nine pollen morphological characters for 69 individuals representing 30 taxonomic entities of Southern Hemisphere bracteate-prostrate Myosotis. Shapes refer to major habitat groups (circles, cushions or mat-forming plants with compact rosettes and branches; squares, pygmy plants belonging to the M. pygmaea complex; triangles, creeping or trailing rosette plants with long branches; diamonds, tag-named entities). Colours indicate different species within each habit group. The three significant clusters found in Bayesian clustering analyses using Mclust are shown as dashed lines (left to right, Clusters 1 to 3); individuals with uncertainty > 0.1 or > 0.2 are enclosed with shaded squares or circles, respectively. A, nMDS 1 vs. nMDS 2; B, nMDS 1 vs. nMDS 3.

Thiers B. [continuously updated]. Index Herbariorum: A global directory of public herbaria and associated staff. New York Botanical Garden's Virtual Herbarium. Available from: http://sweetgum.nybg.org/science/ih/

 Google Scholar

Moar NT. 1993. Pollen grains of New Zealand Dicotyledonous Plants. Lincoln, New Zealand: Maanaki Whenua Press. 200 pp.

 Google Scholar

Grau J, Leins P. 1968. Pollenkorntypen und Sektionegliederung der Gattung Myosotis. Berichte der Deutschen Botanischen Gesellschaft. 81:107–115.

 Google Scholar