Crataegus sect. Macracanthae

Loudon

Arbor. Frutic. Brit. 2: 819. 1838.

Endemic
Treatment appears in FNA Volume 9. Treatment on page 516. Mentioned on page 495, 503, 515, 522, 525.

Shrubs or trees, 20–70 (–80) dm. Stems: trunks 1–several, ± erect to oblique, bark flattened-scaly; compound thorns on trunks present or absent; thorns on twigs determinate, recurved, usually stout, sometimes ± slender. Leaves: blade ± ovate or rhombic to rhombic-elliptic or broadly elliptic, 3–8 (–12) cm, coriaceous or thin, lobes 0 or 3–5 (–8) per side, sinuses shallow, max LII usually 20%, veins (3–) 5–8 per side, absent to sinuses. Inflorescences: branches usually pubescent; symmetric bracteoles present, basal bracteoles absent, falcate bracteoles absent. Flowers: post-mature petals pale paper brown; stamens 10 or 20, anthers red, pink, purple, sometimes white, ivory, or cream. Pomes orange to red; pyrenes dorsally grooved, sides ± pitted or eroded, sometimes plane.

Discussion

Species 8 (8 in the flora).

Section Macracanthae is similar to some species of sect. Coccineae; it differs in possessing more or less pitted pyrenes.

Selected References

None.

Key

1 Pyrenes 2 or 3, (obtuse at ends), sides eroded; petioles usually eglandular. Crataegus ser. Macracanthae
1 Pyrenes 2–5, (obtuse or acute at ends), sides ± smooth to erose or pitted; petioles usually glandular > 2
2 Pyrene sides eroded, (always obtuse at ends); Great Plains. Crataegus ser. Macracanthae
2 Pyrene sides ± smooth to erose or pitted, (sometimes acute at ends); Great Lakes to New England. 64e.Crataegus ser. Anomalae
0.8 cm8 mm <br />0.008 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
cream +, ivory +, white +, pink +  and red +
James B. Phipps +
Loudon +
compound +  and simple +
opposite +  and alternate +
less ovate or rhombic-elliptic +  and rhombic-elliptic +
8 cm80 mm <br />0.08 m <br /> (12 cm120 mm <br />0.12 m <br />) +
rhombic +  and ovate +
2 cm20 mm <br />0.02 m <br /> (8 cm80 mm <br />0.08 m <br />) +
adnate +  and distinct +
crowded +, scattered +  and alternate +
North America +
not +  and aggregated +
unisexual +  and bisexual +
not +  and aggregated +
not +  and aggregated +
yellow +  and red or purplish +
0.6 cm6 mm <br />0.006 m <br /> (2 cm20 mm <br />0.02 m <br />) +
tomentose +  and glabrous +
constricted +
0.2 cm2 mm <br />0.002 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
crassinucellate +
deciduous +
entire +  and serrate +
serrate +  and crenate +
inferior +  and superior +
biseriate +  and clustered +
collateral +  and basal +
0.8 cm8 mm <br />0.008 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
elliptic +  and circular +
0 (?) +  and 4 (?) +
free +  and distinct +
post-mature +
adnate +, free +, connate +  and distinct +
dark gray-brown +  and russet +
exfoliating +  and corrugated +
orange +  and red +
Arbor. Frutic. Brit. +
not arillate +
persistent +
free +  and distinct +
appressed +  and erect +
triangular +
1-50-flowered +  and few-leaved +
eroded +  and pitted +
free +  and distinct +
branched +  and simple +
persistent +
distinct +
exsert +  and lateral +
elongate +
glabrous +  and tomentose +
Crataegus sect. Macracanthae +
Crataegus +
section +
6 cm60 mm <br />0.06 m <br /> (10 cm100 mm <br />0.1 m <br />) +
slender +
1 cm10 mm <br />0.01 m <br /> (6 cm60 mm <br />0.06 m <br />) +
craspedodromous +  and gland-tipped +
inconspicuous +
less erect +  and oblique +
1 +  and several +
determinate +
5 +  and 8 +
tree +  and shrub +