FNA: Pyrus vs. Rosaceae tribe Maleae

Distribution

Europe; Asia; n Africa [Introduced in North America; introduced also in Mexico, South America, Pacific Islands (New Zealand), Australia]

[BONAP county map]

HI; North America; Mexico; Central America; Eurasia; Africa; Atlantic Islands (Madeira) [Introduced in temperate southern hemisphere]

Discussion

Species ca. 25 (6 in the flora).

Pyrus communis is widely cultivated and naturalized in temperate and subtropical regions around the world. The evergreen pear, P. kawakamii, is widely cultivated, especially in California. This taxon has recently been included in P. calleryana (G. Cuizhi and S. A. Spongberg 2003), which is escaped in California. Some of the ornamental pear cultivars available in North America are selections of the oriental P. betulifolia Bunge, with fruits less than 1 cm diameter and leaves tomentose or at least slightly hairy proximally. Pyrus betulifolia is frequently used as a grafting stock. The willow-leaved pear, P. salicifolia Pallas, with densely silvery-pubescent leaves, pendent branches, and brown, pyriform pomes, is rarely cultivated in North America and is not known to escape. The Ussurian pear, P. ussuriensis Maximowicz, is less often cultivated and not known in North America as an escape; it is distinguished by persistent sepals on the fruit and spinulose-serrate leaf margins.

Pyrus may be divided into three groups (J. S. Challice and M. N. Westwood 1973; R. L. Bell 1990; K. Browicz 1993). Pyrus calleryana belongs to the Asian pea pear group. Pyrus pyrifolia belongs to the medium- to large-fruited Asian pears. Both P. communis and P. nivalis belong to the group of European species.

Although the cultivated fruits of apples and pears are easily distinguished, the wild pears and wild apples are sometimes quite similar. Pears differ from apples (Malus) by their hard glossy leaves, leaf margins with callused serrations, flower clusters with a central axis, and fruit with abundant stone or grit cells. The closely related quince (Cydonia oblonga) differs in its basally subcordate leaves that are abaxially tomentose and have entire margins, and its tomentose, pyriform pomes.

The identification of wild pears in North America is difficult. For more information see 4. Pyrus calleryana. The genus requires more study to resolve relationships, taxa, and hybrid origins.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Genera 29, species 550–840+ (18 genera, 270 species, including 18 hybrids, in the flora).

The family name Malaceae Small (1903) is a conserved name, with Malus as its type genus. In contrast, the family name Pyraceae Vest (1818), with Pyrus as its type, is not a conserved name. Although Maleae was published later than Pyreae (1869), a Rosaceae tribe that includes both Malus and Pyrus is to be called Maleae (see Melbourne Code, Article 19.5, Example 5).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Key

1. Branches white-tomentose when young; leaf blades: abaxial surfaces densely whitish gray pubescent.	P. nivalis
1. Branches and leaf blades glabrous or glabrescent	→ 2
2. Leaf margins spinulose-serrate, surfaces brown-lanate when young; flowers 25–35 mm diam.; pomes subglobose.	P. pyrifolia
2. Leaf margins entire or crenulate, serrulate, crenate-dentate, obtusely serrate, or crenate, surfaces glabrous or brown-tomentose abaxially when young; flowers 15–35 mm diam.; pomes globose, subglobose, obovoid, ovoid, or pyriform	→ 3
3. Styles 2 or 3(or 4); pomes blackish brown or dark brown, brown, or yellow-brown (often with pale dots), subglobose, globose, or obovoid, 10–15(–22) mm diam	→ 4
3. Styles 3(–5); pomes yellowish, green, brown, or red (with or without pale dots), globose, subglobose, ovoid, or pyriform, 8–160 × 8–120 mm	→ 5
4. Sepals mostly persistent; pomes subglobose or obovoid, 15–22 mm diam.; styles 3(or 4).	P. serrulata
4. Sepals usually deciduous; pomes globose, 10–15 mm diam.; styles 2 or 3.	P. calleryana
5. Leaf margins densely ciliate when young; sepals persistent; petals (12–)13–15 mm; leaf blades ovate or suborbiculate to elliptic, bases broadly cuneate to almost rounded.	P. communis
5. Leaf margins eciliate or sparsely ciliate when young; sepals deciduous, sometimes persistent; petals 6–12 mm; leaf blades ovate, ovate-lanceolate, or suborbiculate, bases usually cordate, sometimes broadly rounded.	P. cordata

1. Leaf margins usually horny; carpels free; flowers: perianth and androecium perigynous; fruits woody capsules surrounded by a hypanthium, splitting into 5 follicles; seeds winged	Vauquelinia
1. Leaf margins not horny; carpels ± adnate to hypanthium; flowers: perianth and androecium epigynous; fruits pomes; seeds not winged or pyrenes.	→ 2
2. Fruiting carpels woody or bony.	→ 3
3. Leaf margins entire; stipules short-adnate to petiole; stems unarmed; sepals erect in flower; petal base clawed.	Cotoneaster
3. Leaf margins ± serrate, crenate, serrulate, or crenulate, sometimes entire; stipules free; stems usually armed (sometimes with compound thorns), sometimes unarmed; sepals spreading in flower; petal base slightly or barely clawed.	→ 4
4. Leaves persistent or late-deciduous; flowers 3–10(–12) mm diam., hypanthium campanulate; pomes 3–8 mm diam.	Pyracantha
4. Leaves deciduous (sometimes winter-persistent in south); flowers 8–35 mm diam., hypanthium ± obconic; pomes 6–40 mm diam.	→ 5
5. Flowers 8–25 mm diam., stamens 5–20 (rarely 30–45); pomes yellow to red or purplish to black mature, 6–20(–25) mm diam.; pyrenes 1–5; short shoots present; inflorescences 1–50-flowered, domed panicles, corymbose, or flowers solitary.	Crataegus
5. Flowers 25–35 mm diam., stamens 25–35(–40); pomes brownish, 15–40 mm diam.; pyrenes 5; short shoots rare or absent; inflorescences 1(or 2) flowered	Mespilus
2. Fruiting carpels cartilaginous.	→ 6
6. Stems armed (thorns present).>	→ 7
7. Stipules persistent; pedicels short or absent; styles basally connate 1/3 of length; pome flesh without stones; stamens 40–60; fruiting sepals deciduous.	Chaenomeles
7. Stipules usually deciduous or caducous; pedicels present; styles distinct or basally connate; pome flesh with stones (at least near carpels and epidermis); stamens 15–50; fruiting sepals persistent or deciduous.	→ 8
8. Pome flesh with stone cells adjacent to carpels and epidermis; styles basally connate.	Malus
8. Pome flesh with abundant stone or grit cells; styles distinct.	Pyrus
6. Stems unarmed.	→ 9
9. Inflorescences: flowers solitary or 1–5-flowered, corymbs or cymes.	→ 10
10. Pomes yellow; ovules (seeds) many; inflorescences: flowers solitary.	→ 11
11. Leaf margins entire, abaxial surfaces densely villous; buds ovoid, apices obtuse or acuminate, tomentose; young branches tomentose, glabrescent; stipules caducous; flowers 40–50 mm diam., petals white or light pink, suborbiculate, ovate, or obovate, stamens equal to or slightly longer than petals; pomes pyriform or subglobose, 30–50 mm.	Cydonia
10. Pomes pink, yellow-orange, purple, purplish or bluish black, brownish, or nearly black; ovules (seeds) (1 or)2; inflorescences 1–5-flowered, cymes or corymbs.	→ 12
12. Pomes yellow-orange; stipules adnate to petiole and base of blade; petioles short or absent; leaf blades elliptic to oblanceolate or linear.	Peraphyllum
12. Pomes pink, bluish or purplish black, purple, brownish, or nearly black; stipules free; petioles present; leaf blades elliptic, elliptic-oblong, or oblong-ovate to orbiculate.	→ 13
13. Leaves leathery, drought-deciduous or persistent; sepals nearly orbiculate (inner broadly deltate), petals round or kidney-shaped; carpels barely connate or distinct, styles lateral; pomes translucent, vivid pink, drying purplish black.	Malacomeles
13. Leaves membranous to coriaceous (not leathery), deciduous; sepals triangular to lanceolate, petals linear to orbiculate; carpels connate, styles terminal; pomes bluish or purplish to nearly black, pinkish or maroon-purple, dark purple-blue, or brownish.	Amelanchier
9. Inflorescences (4 or)5–400+-flowered, panicles, sometimes racemes, corymbs, or subumbellate.	→ 14
14. Leaves persistent, leathery; carpels basally adnate to hypanthium.	→ 15
15. Leaf margins flat; flowers 15–20 mm diam.; pedicels short or nearly absent; hypanthia usually tomentose; stamens 20; carpels connate, styles (2–)5; pomes soft apricot yellow, 20–30 mm (diam.).	Eriobotrya
15. Leaf margins revolute; flowers 10 mm diam.; pedicels present; hypanthia glabrous or weakly floccose; stamens 10; carpels distinct, styles 2 or 3; pomes usually bright red, sometimes yellow, 5–10 mm	Heteromeles
14. Leaves usually deciduous, sometimes semipersistent or persistent (then margin entire), membranous to ± leathery; carpels adnate to all or 1/3–1/2 of hypanthium.	→ 16
16. Pome flesh with stones or sclereids.	→ 17
17. Inflorescences terminal, 6–400+-flowered flat-topped or rounded panicles; flowers opening after leaf expansion, 5–17 mm diam.; sepals erect or ascending; leaves pinnately divided, sometimes simple or lobed.	Sorbus
17. Inflorescences terminal on short shoots, 4–9-flowered racemes or simple corymbs, umbel-like; flowers developing with or before leaves, 15–45 mm diam.; sepals reflexed; leaves simple.	Pyrus
16. Pome flesh without stones.	→ 18
18. Stipules adnate to petiole, persistent	Aronia
18. Stipules free, caducous or deciduous.	→ 19
19. Leaves persistent or deciduous; inflorescences corymbose or subumbellate; pomes red or black.	Photinia
19. Leaves deciduous; inflorescences racemes; pomes bluish or purplish to nearly black, pinkish or maroon-purple, dark purple-blue, or brownish	Amelanchier