Pollen morphology of Enkianthus (Ericaceae) and its taxonomic significance

Figures & data

Table I. Pollen morphological data based on light microscopic investigation.

Taxon (Collector, Herbarium)		Shape	Size∗	No. of Apertures	Ora	Costae	Shape of ora	Ornamentation∗∗
Section Enkiantella
E. chinensis	(Forrest 30465, TI)	PS	Minute	(2)–3	+	+	Lalongate	FVR / MR–CR
E. deflexus	(Yamazaki 2537, TI)	PS	Minute	3	−	+	Circular	FR
	(Unknown 0814, E 00201099)	PS	Mediae	3–(4)	+	+	Lalongate	MR–CR
	(Hara et al. 21810, TI)	SP	Minute	3–(4)	+	+	Lalongate	FVR
Section Meisteria
E. campanulatus	(Takahashi 511, SAPS)	SP	Mediae	3	+	+	Lalongate	FVR–MVR
	(Tatewaki et al. s.n., SAPS)	SP	Mediae	3	+	+	Circular	FVR
	(Sukawa s.n., SAPS)	P	Mediae	3	+	+	Lalongate	FVR
E. campanulatus var. longilobus	(Tashiro s.n., TI)	PS	Minute	3–(4)	−	+	Lalongate	MR–CR
E. campanulatus var. palibinii	(Tatewaki s.n., SAPS)	SP	Mediae	3	+	+	Lalongate	FVR
E. cernuus	(Takahashi 1827, SAPT)	PS	Minute	3	+	?	Lalongate	FR–G
E. cernuus f. rubens	(Tohyama s.n., SAPS)	SP	Mediae	3	−	+	Circular	FR
	(Matsuda s.n., SAPS)	PS	Minute	3	−	+	Circular	S
E. sikokianus	(Onooka 27206, SAPS)	SP	Minute	3	+	+	Circular	MVR–G
Section Andromedina
E. nudipes	(Onooka 27182, SAPS)	PS	Mediae	4–(5)	+	+	Lalongate	CRP
E. subsessilis	(Ohashi et al. 11824, SAPT)	OS	Minute	4	+	+	Lalongate	CR–CRP
Section Enkianthus
E. perulatus	(Takahashi 509, SAPS)	OS	Mediae	4–5	−	+	?	CRP
E. quinqueflorus	(McClure s.n., TI)	OS	Mediae	4–5	+	+	Lalongate	MR–CR
E. serotinus	(Togashi & Murata 8032, TI)	OS	Mediae	4–5	−	+	?	MR–CRP
Explanation of symbols: OS – Oblate spheroidal; PS – Prolate spheroidal; SP – Subprolate; P – Prolate; ∗ minute – 10–25 µm, mediae – 25–50 µm; ‘+’ – Distinct, ‘‐’– Indistinct; ‘?’ – Not clear; ∗∗ Scanning electron microscopic observation; CR – Coarsely rugulate; CRP – Coarsely rugulate‐psilate; FR – Finely rugulate; FVR – Finely verrucate‐rugulate; G – Granulate; MR – Moderately rugulate; MVR – Moderately verrucate‐rugulate; S – Scabrate with granules‐spinules.

Table II. Variation in pollen characters of Enkianthus; showing mean value and standard deviation (minimum – maximum values in parenthesis).

Taxon (Collector, Herbarium)		P (µm)	E (µm)	P/E	Apocolpial Exine Thickness	Mesocolpial Exine Thickness	Colpus		L/P
							Length (L) (µm)	Width (µm)
Section	Enkiantella
E. chinensis	(Forrest 30465, TI)	23.8±0.7 (23.0–25.4)	21.9±1.1 (19.7–23.3)	1.09	1.4±0.5 (0.7–2.2)	1.5±0.3 (1.2–2.2)	17.8±1.3 (16.3–19.7)	1.7±0.3 (1.2–1.9)	0.75
E. deflexus	(Yamazaki 2537, TI)	24.5±1.2 (23.3–26.6)	23.0±1.0 (21.8–24.5)	1.07	1.6±0.5 (1.0–2.4)	1.7±0.4 (1.2–2.2)	18.6±1.1 (16.8–20.0)	2.3±0.5 (1.9–3.6)	0.76
	(Unknown 0814, E 00201099)	25.4±1.3 (23.5–27.8)	23.4±2.1 (20.6–26.4)	1.08	2.1±0.3 (1.7–2.4)	2.0±0.2 (1.9–2.4)	19.9±0.7 (19.2–21.1)	2.1±0.2 (1.9–2.4)	0.78
	(Hara et al. 21810, TI)	24.4±2.8 (20.4–30.0)	21.4±4.4 (17.0–32.2)	1.14	1.9±0.4 (1.4–2.6)	1.9±0.4 (1.2–2.4)	16.9±2.0 (13.9–19.2)	1.6±0.5 (1.2–2.4)	0.69
Section Meisteria
E. campanulatus	(Takahashi 511, SAPS)	29.9±0.5 (29.4–30.7)	23.0±1.2 (21.5–25.1)	1.30	1.9±0.2 (1.7–2.0)	1.5±0.2 (1.3–1.8)	24.3±1.0 (23.1–26.4)	0.7±0.4 (0.3–1.7)	0.81
	(Tatewaki et al. s.n., SAPS)	29.2±1.3 (27.6–31.2 )	24.4±0.8 (23.5–26.4)	1.20	2.6±1.0 (1.4–4.8)	2.2±0.7 (1.2–3.6)	21.7±2.1 (19.2–26.4)	2.3±0.8 (0.7–3.4)	0.74
	(Sukawa s.n., SAPS)	29.1±1.0 (27.6–30.2)	19.6±3.2 (16.3–24.5)	1.48	1.6±0.6 (0.7–1.9)	1.4±0.3 (1.0–1.7)	21.9±1.3 (19.7–23.0)	2.2±0.3 (1.9–2.4)	0.75
E. campanulatus var. longilobus	(Tashiro s.n., TI)	23.6±1.1 (21.8–25.0)	22.2±2.0 (19.7–26.5)	1.06	1.7±0.3 (1.4–2.2)	1.4±0.3 (1.0–1.7)	18.8±1.9 (14.9–21.1)	1.8±0.3 (1.4–2.4)	0.80
E. campanulatus var. palibinii	(Tatewaki s.n., SAPS)	26.8±0.8 (25.2–27.6)	24.4±1.5 (22.8–26.9)	1.10	1.5±0.3 (1.2–1.9)	1.7±0.3 (1.2–2.2)	20.4±0.9 (19.2–21.6)	2.0±0.3 (1.4–2.4)	0.76
E. cernuus	(Takahashi 1827, SAPT)	17.1±0.4 (16.5–17.7)	15.1±1.0 (14.0–16.7)	1.13	1.1±0.2 (0.8–1.3)	1.1±0.3 (0.5–1.3)	14.4±1.1 (13.2–14.9)	0.9±0.6 (0.5–1.3)	0.84
E. cernuus f. rubens	(Tohyama s.n., SAPS)	25.4±1.8 (22.8–28.8)	20.8±0.9 (19.7–2.2)	1.22	1.7±0.2 (1.4–2.0)	1.4±0.2 (1.2–1.9)	19.3±0.9 (18.0–21.6)	2.1±0.5 (1.2–2.4)	0.76
	(Matsuda s.n., SAPS)	23.6±3.3 (18.0–28.8)	21.9±2.9 (16.8–25.2)	1.07	1.6±0.6 (0.5–2.4)	1.6±0.7 (0.5–2.4)	17.3±2.3 (13.2–20.4)	1.9±0.3 (1.4–2.4)	0.73
E. sikokianus	(Onooka 27206, SAPS)	23.7±1.5 (21.6–26.4)	20.8±0.9 (19.2–22.1)	1.14	1.0±0.2 (0.7–1.2)	1. 3±0.3 (1.0–1.9)	18.7±1.6 (15.6–20.6)	2.0±0.3 (1.7–2.9)	0.79
Section	Andromedina
E. nudipes	(Onooka 27182, SAPS)	29.0±2.1 (25.2–32.2)	27.1±2.0 (24.0–30.0)	1.07	1.9±0.3 (1.4–2.4)	1.9±0.5 (1.4–2.6)	18.3±1.4 (16.3–20.4)	1.5±0.5 (1.2–2.4)	0.63
E. subsessilis	(Ohashi et al. 11824, SAPT)	23.5±0.8 (22.8–24.8)	24.3±0.9 (23.3–25.9)	0.97	1.9±0.2 (1.7–2.1)	2.0±0.1 (1.8–2.1)	13.1±0.6 (11.6–14.0)	1.3±0.4 (0.7–1.9)	0.56
Section	Enkianthus
E. perulatus	(Takahashi 509, SAPS)	27.1±0.8 (25.6–28.1)	27.9±1.1 (26.1–29.4)	0.97	1.8±0.1 (1.7–2.0)	1.7±0.2 (1.5–2.0)	16.8±0.7 (15.7–18.2)	1.3±0.6 (0.5–2.6)	0.62
E. quinqueflorus	(McClure s.n., TI)	28.5±0.7 (27.6–29.0)	29.9±1.3 (28.8–32.0)	0.95	2.0±0.3 (1.4–2.4)	1.5±0.3 (1.2–1.9)	16.1±1.9 (14.9–19.4)	1.8±0.4 (1.4–2.4)	0.56
E. serotinus	(Togashi & Murata 8032, TI)	29.6±1.9 (26.4–33.6)	30.6±1.3 (28.8–33.1)	0.97	2.0±0.4 (1.2–2.4)	1.7±0.2 (1.4–1.9)	17.8±2.2 (14.9–22.8)	2.3±0.6 (1.7–3.8)	0.60
P – polar axis; E – equatorial diameter.

Table III. Matrix of palynological characters and taxa. Pollen observation of Clethra alnifolia (Zhang & Anderberg, 2002).

Pollen characters:	A	B	C	D	E	F
Clethra alnifolia	0	0	0	2	0	4
E. deflexus	0	1	0	0	0	0
E. chinensis	0	0	0	0	0	0
E. cernuus	0	0	0	0	0	1
E. campanulatus	0	1	0	1	1	0
E. subsessilis	1	0	1	2	0	3
E. nudipes	1	0	1	0	1	3
E. perulatus	2	0	1	2	1	3
E. quinqueflorus	2	0	1	2	1	2
E. serotinus	2	0	1	2	1	2
Explanation of symbols: A – Pollen with mainly 3 apertures (0); with mainly 4 apertures (1); with 4 to 5 apertures (2). B – Colpus membrane granulate (0); smooth (1). C – L/P 0.69–0.84 (0); 0.56–0.63 (1). D – Pollen grains prolate spheriodal (0); subprolate (1); oblate spheriodal (2). E – Pollen grains minute (0); medium (1). F – Exine sculptures fine verrucate‐rugulate to fine rugulate (0); granulate (1); mainly medium (– coarse) rugulate‐psilate (2); mainly coarse rugulate‐psilate (3); psilate (4).

Figure 1 Scanning electron micrographs ofEnkianthus pollen. A–C. E. chinensis (Forrest 30465, TI). D–E. E. deflexus (Yamazaki 2537, TI). F–K. E. campanulatus: (F, J, & K) Takahashi 511, SAPS. (G & I) Sukawa s.n., SAPS. (H) Tatewaki et al. s.n., SAPS. L–M. E. campanulatus var. longilobus (Tashiro s.n.; TI). N, O. E. campanulatus var. palibinii (Tatewaki s.n.; SAPS). Pollen grains in equatorial view (A, D, F, G, L & N); syncolpate grain at polar view (H); micrographs with mesocolpial exine details (B, E, I, J, K, M & O); apocolpial exine (C). Scale bar – 5 µm (A, D, F–H, L, N); 1 µm (B, C, E, I–K, M, O).

Figure 2 Scanning electron micrographs ofEnkianthus pollen. A, B. E. cernuus (Takahashi 1827; SAPT). C–F. E. cernuus f. rubens: (C–E) M. Tohyama s.n., SAPS; (F) Matsuda s.n., SAPS. G–K. E. sikokianus: (G, H, J & K) Onooka 27245, SAPS; (I) Onooka 27206, SAPS. L–O. E. nudipes: (L, M & O) Onooka 27182, SAPS; (N) Nakajima s.n., SAPS. Pollen grains in equatorial view (C, G, L); pollen grain in polar view (H, M); details of mesocolpial exine (A, D‐F, I, J, N & O); apocolpial exine (B & K). Scale bar – 1 µm (A, B, D–F, I–K, N, O); 5 µm (C, G, H, L, M).

Figure 3 Scanning electron micrographs ofEnkianthus pollen. A. E. nudipes: Onooka 27182, SAPS; B–F. E. subsessilis: (B & D) Tohyama s.n., SAPS; (C, E & F) Ohashi et al. 11824, SAPT. G–I. E. perulatus: (G, H) Sarwar & Takahashi s.n., SAPS; (I) Takahashi 509, SAPS. J–L. E. quinqueflorus (McClure s.n.; TI). M–O. E. serotinus (Togashi & Murata 8032; TI). Pollen grains in equatorial view (B, G & J); pollen grain in polar view (C & M); details of mesocolpial exine (D, E, H, K & N); apocolpial exine (A, F, I, L & O). Scale bar – 1 µm (A, D–F, H, I, K, L, N); 5 µm (B, C, G, J, M).

Figure 4 Morphological variation of mesocolpial exine sculpture inEnkianthus: (A) Granulate; (B) Scabrate with minute granules‐spinules; (C–E) Finely verrucate‐rugulate with minute granules; (F) Finely verrucate‐rugulate with minute granules; (G) Finely verrucate‐rugulate to moderately verrucate‐rugulate with minute granules; (H) Coarsely rugulate with minute granules; (I) Coarsely rugulate with faintly minute granules; (J) Coarsely rugulate‐psilate without granules. Scale bar – 1 µm (A–J).

Figure 5 Palynological data incorporated on phylogenetic tree ofEnkianthus by Anderberg (1994); C. – Clethra; E. – Enkianthus. For character states see Table III.

Zhang , X. P. and Anderberg , A. A. 2002 . Pollen morphology in the ericoid clade of the order Ericales, with special emphasis on Cyrillaceae. . Grana , 41 : 201 – 215 .

 Web of Science ®Google Scholar

Anderberg , A. A. 1994 . Cladistic analysis of Enkianthus with notes on the early diversification of the Ericaceae. . Nord. J. Bot. , 14 : 385 – 401 .

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