Flora of China
  FOC Vol.8 (2001)              | Family List  Saxifragaceae  PDF     | Link Font:+ Big | - Small
   Saxifragaceae  A. L. Jussieu
虎耳草科   hu er cao ke
Authors:Pan Jintang , Gu Cuizhi (Ku Tsue-chih), Huang Shumei (Hwang Shu-mei), Wei Zhaofen (Wei Chao-fen), Jin Shuying , Lu Lingdi (Lu Ling-ti); Shinobu Akiyama, Crinan Alexander, Bruce Bartholomew, James Cullen, Richard J. Gornall, Ulla-Maj Hultgård, Hideaki Ohba, Douglas E. Soltis


Herbs or shrubs, rarely trees or vines. Leaves simple or compound, usually alternate or opposite, usually exstipulate. Flowers usually in cymes, panicles, or racemes, rarely solitary, usually bisexual, rarely unisexual, hypogynous or ± epigynous, rarely perigynous, usually biperianthial, rarely monochlamydeous, actinomorphic, rarely zygomorphic, 4- or 5(-10)-merous. Sepals sometimes petal-like. Petals usually free, sometimes absent. Stamens (4 or)5-10 or many; filaments free; anthers 2-loculed; staminodes often present. Carpels 2, rarely 3-5(-10), usually ± connate; ovary superior or semi-inferior to inferior, 2- or 3-5(-10)-loculed with axile placentation, or 1-loculed with parietal placentation, rarely with apical placentation; ovules usually many, 2- to many seriate, crassinucellate or tenuinucellate, sometimes with transitional forms; integument 1- or 2-seriate; styles free or ± connate. Fruit a capsule or berry, rarely a follicle or drupe. Seeds albuminous, rarely not so; albumen of cellular type, rarely of nuclear type; embryo small.

About 80 genera and 1200 species: worldwide; 29 genera (two endemic), and 545 species (354 endemic, seven introduced) in China.

During the past several years, cladistic analyses of morphological, chemical, and DNA data have made it clear that the recognition of the Saxifragaceae sensu lato (Engler, Nat. Pflanzenfam. 18a: 74-226. 1928) is untenable. Among the angiosperm families, Saxifragaceae sensu lato may in fact represent the most extreme example of a polyphyletic assemblage. For example, recent analyses of DNA sequence data indicate that these taxa represent at least ten separate evolutionary lines, many of which are only distantly related to one another (Morgan & Soltis, Ann. Missouri Bot. Gard. 80: 631-660. 1993; Soltis & Soltis, Amer. J. Bot. 84: 504-522. 1997). Furthermore, very large molecular phylogenetic analyses of hundreds of angiosperms indicate that these separate lineages are distributed among four of the six traditionally recognized subclasses of dicotyledons (Savolainen et al., Syst. Biol. 49: 306-362. 2000; Soltis et al., Nature 402: 402-404. 1999). These recent studies have also greatly clarified how this phylogenetically diverse assemblage should be divided into families and treated taxonomically (see The Angiosperm Phylogeny Group (APG), Ann. Missouri Bot. Gard. 85: 531-553. 1998). Recent studies of DNA sequence data have clarified both the circumscription and affinities of a narrowly defined Saxifragaceae (Saxifragaceae sensu stricto) and Hydrangeaceae (Soltis et al., Amer. J. Bot. 82: 504-514. 1995; Savolainen et al., loc. cit.; Soltis et al., loc. cit. 1999). Saxifragaceae sensu stricto should consist only of Saxifragoideae, a group of about 30 herbaceous genera. Members of Saxifragaceae sensu stricto from the Chinese flora include Astilbe, Astilboides, Bergenia, Chrysosplenium, Mitella, Mukdenia, Oresitrophe, Rodgersia, Saxifraga, Tanakaea, Tiarella, and the recently described Saniculiphyllum. Close relatives of Saxifragaceae sensu stricto include Itea, Penthorum, and Ribes. These genera, the sole members of Iteoideae, Penthoroideae, and Ribesioideae, respectively, are also best treated in separate families: Iteaceae, Penthoraceae, and Grossulariaceae (see APG, loc. cit.). These taxa, as well as several others, such as Crassulaceae, are basal to a large assemblage of taxa, most of which were traditionally placed in Rosidae. Sequence data also indicate that Parnassia (the sole member of the Parnassioideae) is a more derived member of the rosid alliance, most closely related to Brexia and Lepuropetalon (also part of Saxifragaceae sensu lato) and Celastraceae. Parnassia and Lepuropetalon should be placed in Parnassiaceae with Brexia part of an expanded Celastraceae (APG, loc. cit.).

Both morphological and molecular data indicate that Hydrangeoideae and Escallonioideae are, in contrast, allied with taxa traditionally placed in Asteridae. Hydrangeoideae are a well-defined, monophyletic lineage that should be treated as Hydrangeaceae. In China they include Cardiandra, Decumaria, Deinanthe, Deutzia, Dichroa, Hydrangea, Kirengeshoma, Philadelphus, Pileostegia, Platycrater, and Schizophragma, and are closely allied with families such as Cornaceae, Loasaceae, and Nyssaceae. Escallonioideae appear to be polyphyletic, and this group of approximately 14 genera is in need of thorough study. Members of this subfamily are allied with several different lineages of higher asterids. Polyosma, the only member of Escallonioideae in China, appears closely allied with Caprifoliaceae (Xiang & Soltis in Boufford & Ohba, Sino-Japanese Flora: its Characteristics and Diversification, 1998).

Nevertheless, in the present account, the Saxifragaceae are retained in the sense of FRPS, using the same sequence of genera and indicating the subfamilies in the key below, in order to facilitate comparison with that flora.

The genus Changiodendron R. H. Miao (Acta Sci. Nat. Univ. Sunyatseni 34: 65. 1995) and its single species, C. guangxiense R. H. Miao (loc. cit.: 66), was described from Guangxi (Napo Xian) and stated to belong to the Iteaceae (i.e., Iteoideae). However, Peng (Acta Bot. Yunnan. 18: 299-300. 1996) demonstrated that C. guangxiense is a synonym of Sabia parviflora Wallich (Sabiaceae).

Pan Jin-tang. 1992. Saxifragaceae (1) [Penthoroideae, Saxifragoideae]. In: Pan Jin-tang, ed., Fl. Reipubl. Popularis Sin. 34(2): 1-309; Hwang Shu-mei, Wei Chao-fen, Lu Ling-ti, Ku Tsue-chih & Jin Shu-ying. 1995. Saxifragaceae (2) [Parnassioideae, Hydrangeoideae, Escallonioideae, Iteoideae, Ribesioideae]. In: Lu Ling-ti & Hwang Shu-mei, eds., Fl. Reipubl. Popularis Sin. 35(1): 1-406.

1Plants woody or herbs; leaves opposite or alternate, rarely subverticillate or cespitose.(2)
+Plants herbs; leaves usually alternate.(16)
2(1)Stamens as many as sepals; leaves usually alternate, opposite or subopposite in Polyosma.(3)
+Stamens ca. 2 × as many as sepals, sometimes more; leaves usually opposite or verticillate, alternate or fascicled in Cardiandra (Hydrangeoideae).(5)
3(2)Leaves opposite or subopposite; fruit a 1-seeded berry (Escallonioideae)27  Polyosma    多香木属
+Leaves alternate; fruit a capsule or many-seeded berry.(4)
4(3)Leaves never lobed; stipules present, linear; sepals not petal-like; petals narrow; ovary 2-loculed; fruit a capsule (Iteoideae)28  Itea    鼠刺属
+Leaves often palmately lobed; stipules absent, spines or prickles sometimes present; sepals usually petal-like; petals usually scalelike; ovary 1-loculed; fruit a berry (Ribesioideae)29  Ribes    茶(藨)子属
5(2)Herbs; leaf blade palmately lobed; stamens 3 × as many as petals16  Kirengeshoma    黄山梅属
+Shrubs, scandent shrubs, or herbs; leaf blade not palmately lobed; stamens numerous or 2 × as many as petals.(6)
6(5)Filaments subulate, flat, apex 2-dentate or 2-lobed; shrubs; calyx lobes never enlarged and petaloid.(7)
+Filaments linear, neither subulate nor flat; herbs or shrubs; calyx lobes sometimes enlarged and petaloid.(8)
7(6)Leaves often stellate hairy; petals 5; stamens 10(-15); capsule 3-5-valved, loculicidally dehiscent17  Deutzia    溲疏属
+Leaves not stellate hairy; petals 4; stamens 20-40; capsule 4-valved, loculicidally or septicidally dehiscent18  Philadelphus    山梅花属
8(6)Inflorescences with all flowers fertile; calyx lobes never petaloid.(9)
+Inflorescences with both fertile and sterile flowers (except Schizophragma crassum); calyx lobes ± petaloid.(12)
9(8)Styles 2-6.(10)
+Style 1.(11)
10(9)Fruit a fleshy berry21  Dichroa    常山属
+Fruit a capsule26  Hydrangea    绣球属
11(9)Sepals and petals 7-10, apex free; stamens 20-30; stigma discoid19  Decumaria    赤壁木属
+Sepals and petals 4 or 5, apex connate and forming a calyptra; stamens 8-10; stigma conical20  Pileostegia    冠盖藤属
12(8)Leaves alternate; anthers obcordate, apex truncate, connective dilated22  Cardiandra    草绣球属
+Leaves opposite or verticillate; anthers oblong, ellipsoid, or subglobose, apex obtuse to subrounded, connective not dilated.(13)
13(12)Style 1; sterile flowers (if present) with 1(-3 in Schizophragma integrifolium) enlarged calyx lobe24  Schizophragma    钻地风属
+Styles 2 or more; sterile flowers (if present) with more than 1 enlarged calyx lobe.(14)
14(13)Sterile flowers with connate, enlarged, petaloid calyx lobes23  Platycrater    蛛网萼属
+Sterile flowers with free, enlarged, petaloid calyx lobes, or sterile flowers absent.(15)
15(14)Herbs perennial or subshrubs, with horizontal rhizomes; stem simple; petals imbricate in bud; styles 5, connate into a column25  Deinanthe    叉叶蓝属
+Shrubs or subshrubs, sometimes scandent, rarely small trees; stems often branched; petals valvate in bud; styles 2-5, free or connate only at base26  Hydrangea    绣球属
16(1)Flower solitary; stamens 5, staminodes 5, conspicuous, spreading into a lamina, usually distally lobed, inserted opposite petals; ovary 1-loculed (Parnassioideae)15  Parnassia    梅花草属
+Flowers usually in cymes, racemes, or panicles, sometimes solitary; stamens 4-14, staminodes absent; ovary 1-5-loculed.(17)
17(16)Leaves membranous; inflorescence a helicoid cyme; stamens (6-)10; ovary 5-loculed (Penthoroideae)1  Penthorum    扯根菜属
+Leaves usually not membranous; inflorescence often not helicoid; stamens 4-14; ovary usually less than 5-loculed, rarely more (Saxifragoideae).(18)
18(17)Leaves usually compound, rarely simple; sepals 4 or 5, sometimes 1-3 or absent; carpels 2 or 3(or 4); ovary 2- or 3(or 4)-loculed with axile placentation or 1-loculed with marginal placentation.(19)
+Leaves simple; petals 5(or 6) or absent; carpels 2(-5); ovary 2(-5)-loculed with axile placentation, or 1-loculed with marginal or parietal placentation, sometimes proximally with 2 terminal, parietal placentas and distally with marginal placentation.(21)
19(18)Leaves simple, leaf blade peltate, margin palmatilobed; petals 4 or 5; stamens (6-)8; carpels 2(-4), ovary 2(-4)-loculed2  Astilboides    大叶子属
+Leaves usually compound (or, if simple, leaf blade not peltate), usually 3-5-lobed; petals 1-5 or absent; stamens (5-)8-10(-14); carpels 2 or 3, ovary 1-3-loculed.(20)
20(19)Leaves palmately, pinnately, or subpinnately compound; bract absent; sepals (4 or)5(-7); petals usually absent; stamens 10(-14); ovary 2- or 3-loculed with axile placentation3  Rodgersia    鬼灯檠属
+Leaves ternately compound, rarely simple; bracts conspicuous; sepals (4 or)5; petals 1-5, sometimes more or absent; stamens (5-)8-10; ovary 2(or 3)-loculed with axile placentation or 1-loculed with marginal placentation4  Astilbe    落新妇属
21(18)Leaves all basal; bracts absent; sepals 5-7 or absent; stamens 5 or 6 or 10-14.(22)
+Leaves all basal or both basal and cauline; bracts conspicuous; sepals 4 or 5(-7); petals 5 or absent; stamens 4-10.(23)
22(21)Leaf blade ovate to cordate, glandular hairy abaxially, glabrous adaxially, margin irregularly dentate; sepals 5-7, unequal, many veined; petals absent; stamens 10-145  Oresitrophe    独根草属
+Leaves broadly ovate to orbicular, glabrous on both surfaces, margin palmately 5-7(-9)-cleft, lobes serrate; sepals 5 or 6, subequal, 1-veined; petals 5 or 6(or 7), white; stamens 5 or 6(or 7)6  Mukdenia    槭叶草属
23(21)Carpels 2 or 3, ovary 2- or 3-loculed7  Saniculiphyllum    变豆叶草属
+Carpels 2, ovary 1- or 2-loculed, or proximally 2-loculed and distally 1-loculed.(24)
24(23)Sepals 5; petals 5; stamens 10; ovary 2-loculed with axile placentation or 1-loculed with marginal placentation.(25)
+Sepals 4 or 5(-7); petals 5 or absent; stamens 4-10; ovary usually 1-loculed with 2 parietal placentas, or proximally 2-loculed with axile placentation and distally 1-loculed with marginal placentation.(27)
25(24)Herbs perennial, rarely annual or biennial; inflorescence a cyme or flower solitary; flowers usually actinomorphic, rarely zygomorphic; receptacle cyathiform or saucer-shaped; fruit a capsule, rarely a follicle10  Saxifraga    虎耳草属
+Herbs perennial; inflorescence a cyme; flowers actinomorphic; receptacle cyathiform; fruit a capsule.(26)
26(25)Leaves all basal, petiole short, broad, sheathing at base, leaf blade not peltate, margin entire or dentate; hypanthium scarcely adnate to ovary; petals white, red, or purple, margin entire; ovary subsuperior, proximally 2-loculed with axile placentation 8  Bergenia    岩白菜属
+Leaves both basal and cauline, stipules membranous, leaf blade peltate, margin palmatilobed; hypanthium proximally adnate to ovary; petals yellowish, margin usually sparsely denticulate; ovary semi-inferior, 2-loculed with axile placentation; seeds tuberc9  Peltoboykinia    涧边草属
27(24)Stipules conspicuous; sepals 5; petals 5, sometimes absent; stamens 5 or 10.(28)
+Stipules absent; sepals 4 or 5(-7); petals absent; stamens 4-10.(29)
28(27)Leaves simple or trifoliolate; inflorescence terminal or axillary, racemose or paniculate; petals entire; stamens 10; fruit with 2 distinctly unequal carpels11  Tiarella    黄水枝属
+Leaves simple; inflorescence terminal, racemose; petals usually pinnatifid, rarely entire; stamens 5 or 10; fruit with 2 subequal carpels12  Mitella    唢呐草属
29(27)Cauline leaves alternate or opposite; inflorescence usually cymose; sepals 4(or 5); stamens 4-8(-10); ovary subsuperior or semi-inferior to subinferior14  Chrysosplenium    金腰属
+Cauline leaves absent; inflorescence paniculate or racemose; sepals (4 or)5(-7); stamens 8-10; ovary subsuperior13  Tanakaea    峨屏草属
   List of lower taxa