Rosaceae tribe Spiraeeae

de Candolle

in A. P de Candolle and A. L. P. P. de Candolle, Prodr. 2: 541. 1825.

Treatment appears in FNA Volume 9. Treatment on page 398. Mentioned on page 21, 412, 414, 415, 416.

Shrubs, subshrubs, or herbs, perennial (Aruncus); unarmed. Leaves alternate, simple or pinnately compound; stipules absent; venation pinnate, sometimes palmate. Flowers: perianth and androecium perigynous; epicalyx bractlets absent or present; hypanthium shallowly bowl-shaped, hemispheric, campanulate, patelliform, +/- crateriform, or turbinate; torus absent, minute, or thickened; carpels 3–5(or 6)[–8], distinct, free or adnate to hypanthium base, styles +/- terminal, distinct; ovules 2–5, apical, collateral or clustered. Fruits aggregated follicles or achenes (Holodiscus); styles deciduous or persistent, not elongate.

Distribution

North America, Mexico, Central America, South America, Eurasia, introduced widely.

Discussion

Genera 8, species ca. 130 (6 genera, 25 species, including 3 hybrids, in the flora).

The two genera not present in North America north of Mexico are the southeastern European-western Asian Sibiraea Maximowicz (five species) and the Mexican Xerospiraea J. Henrickson (one species).

The base chromosome number for Spiraeeae is x = 9.

Selected References

None.

Key

1 Herbs, perennial; flowers unisexual; hypanthia shallowly bowl-shaped. Aruncus
1 Shrubs or subshrubs; flowers bisexual; hypanthia hemispheric, campanulate, patelliform, +/- crateriform, or turbinate > 2
2 Subshrubs; leaves 2–3(–5)-ternate, primarily crowded basally. Luetkea
2 Shrubs; leaves simple, cauline (tightly clustered in Petrophytum) > 3
3 Leaves deciduous, herbaceous, membranous, chartaceous, rarely coriaceous; stems erect, arching, or ascending, sometimes spreading to prostrate in Spiraea > 4
3 Leaves persistent, often marcescent, coriaceous; stems prostrate (mat-forming), sometimes ascending or erect in Petrophytum > 5
4 Fruits aggregated follicles; inflorescences panicles or corymbiform or racemiform; carpels free; petals greenish, yellowish, white, pink, or purple. Spiraea
4 Fruits aggregated achenes; inflorescences panicles; carpels adnate to hypanthium base; petals usually white, sometimes pink tinged, rarely pink. Holodiscus
5 Inflorescences panicles; petals white; stamens 20–40. Petrophytum
5 Inflorescences: flowers solitary; petals pink to pinkish, often purple tinged; stamens 7–12. Kelseya