Saxifraga sect. Porphyrion in Flora of China @ efloras.org

6. Saxifraga sect. Porphyrion Tausch, Hort. Canal. 1. 1823.

垫状组 dian zhuang zu

Antiphylla Haworth.

Herbs perennial, forming dense cushions or mats, lacking basal bulbils. Leaves alternate or opposite; petiole scarcely differentiated; leaf blade leathery, usually stiff and hard, usually coated with a white deposit of calcium carbonate derived from chalk glands set submarginally (rarely marginally) in pits in adaxial surface, margin entire but often denticulate-ciliate proximally; foliar crystals absent. Inflorescence cymose or flower solitary. Flowers bisexual, actinomorphic, 4- or 5-merous. Petals white, pink, or red, rarely yellow, not callose. Filaments subulate to linear; pollen 2-nucleate, exine tectum coarsely striate. Carpels connate proximally or for most of placental region, dehiscing distally in fruit; ovary subsuperior to subinferior. Integuments 2.

About 90 species: primarily in Asia and Europe, mainly Himalayan and montane, also extending into North America; 25 species (17 endemic) in China.

1 Shoot leaves opposite; flower solitary. (2)

+ Shoot leaves alternate; flowers 1 to several. (8)

2 (1) Shoot leaves with 1(-3) chalk glands. (3)

+ Shoot leaves with 3-7 chalk glands. (5)

3 (2) Leaves of a pair meeting at an acute angle, margin denticulate-ciliate proximally; all flowers 5-merous 211 S. georgei

+ Leaves of a pair confluent at base, margin glabrous; all or most flowers 4-merous. (4)

4 (3) Petals 2-3 × as long as sepals; leaves with 1-3 chalk glands 213 S. decussata

+ Petals less than 2 × as long as sepals; leaves with 1 chalk gland 215 S. nana

5 (2) Leaves of a pair meeting at an acute angle, margin denticulate-ciliate proximally; all flowers 5-merous. (6)

+ Leaves of a pair confluent at base, margin glabrous; all or most flowers 4-merous. (7)

6 (5) All leaves in opposite pairs 210 S. oppositifolia

+ Some leaves on vigorous shoots 3-verticillate 212 S. subternata

7 (5) Flowering stem 0.7-1.5 cm, with 1 or 2 pairs of opposite cauline leaves 214 S. monantha

+ Flowering stem absent to 5 mm 213 S. decussata

8 (1) Petals yellow. (9)

+ Petals white, pink, or red. (12)

9 (8) Cyme 2- or 3-flowered 196 S. rotundipetala

+ Flower solitary. (10)

10 (9) Flowering stem more than 2 cm 194 S. kongboensis

+ Flowering stem to 1 cm. (11)

11 (10) Stamens equaling or exceeding petals; basal 2/3 of leaf margin denticulate-ciliate 195 S. nambulana

+ Stamens much shorter than petals; basal 1/3 of leaf margin minutely setose-ciliate 193 S. elliotii

12 (8) Corolla shorter than or subequaling calyx. (13)

+ Corolla at least 1.5 × as long as calyx. (14)

13 (12) Flower solitary, sessile or borne on a stem to 1 cm 192 S. rupicola

+ Flowers 2-7, borne on a stem 1-4 cm 191 S. chionophila

14 (12) Cyme 2- to several flowered. (15)

+ Flower solitary. (19)

15 (14) Cyme apparently sessile, embedded among leafy shoots; petals white 200 S. clivorum

+ Cyme elevated above leafy shoots on a stem 1.5-7 cm; petals reddish, pink, or white. (16)

16 (15) Sepals without chalk glands. (17)

+ Sepals with 1-3 chalk glands. (18)

17 (16) Styles less than 2.5 mm 197 S. afghanica

+ Styles more than 4 mm 201 S. pulchra

18 (16) Petals pink or purple 199 S. decora

+ Petals white, rarely pale pink 198 S. andersonii

19 (14) Leaves with 1 chalk gland. (20)

+ Leaves with more than 1 chalk gland. (21)

20 (19) Petals more than 2 mm wide 208 S. subsessiliflora

+ Petals less than 2 mm wide 209 S. pulvinaria

21 (19) Flowering stem ± absent 207 S. likiangensis

+ Flowering stem present. (22)

22 (21) Sepals glabrous abaxially 204 S. saxicola

+ Sepals glandular hairy abaxially. (23)

23 (22) Petals purple or reddish. (24)

+ Petals white. (25)

24 (23) Petals at least 9 mm 203 S. ludlowii

+ Petals 4-4.5 mm 206 S. saxatilis

25 (23) Petals less than 5 mm 206 S. saxatilis

+ Petals at least 6 mm. (26)

26 (25) Flowering stem to 1 cm 202 S. doyalana

+ Flowering stem more than 2 cm 205 S. unguipetala

List of lower taxa