Crataegus sect. Douglasia

Loudon

Arbor. Frutic. Brit. 2: 823. 1838.

Endemic
Treatment appears in FNA Volume 9. Treatment on page 502. Mentioned on page 495, 508, 511, 633.

Shrubs or trees, (20–) 30–100 (–140) dm. Stems: trunks 1–few, usually ± erect, bark plated, ± exfoliating; compound thorns on trunks sometimes present; thorns on twigs determinate, usually numerous, straight to ± recurved, slender to stout. Leaves: blade ± rhombic to ± elliptic, elliptic-oblong, or ovate-rhombic, sometimes ± obovate, oblanceolate, or suborbiculate, 3–8 cm, ± coriaceous to ± thin, lobes 0 or 1–4 per side, obscure to evident and sinuses shallow to deep, veins (3 or) 4–9 (–12) per side, absent to sinuses. Inflorescences: branches glabrous or pubescent; symmetric bracteoles present, basal stipuliform, falcate bracteoles absent. Flowers: post-mature petals pale paper brown; stamens 5 or 10–20, anthers white to ivory, pink, or purple, sometimes puce. Pomes bright or deep red to purple or black (late Aug), reddish purple to black (late Sep); pyrene sides usually pitted, sometimes plane.

Distribution

w, nc North America

Discussion

Species 16 (16 in the flora).

Section Douglasia comprises all the North American hawthorns (except Crataegus brachyacantha) with purple (burgundy in two) to black fully mature fruit, usually fairly short (1.5–3.5 cm) thorns, and laterally eroded pyrenes. The lateral erosion or pitting on the pyrenes is not always very deep or as conspicuous as in C. macracantha and close allies.

Selected References

None.

Key

1 Leaves: blades narrow, more than 2:1, lobes 0, veins 6–8(–12) per side; flowers 10–13 mm diam.; stamens 20, anthers cream; bark on younger 2–5 cm thick branches often shining coppery, horizontal lenticels present. Crataegus ser. Cerrones
1 Leaves: blades usually broader, less than 1.6:1, lobes 0 or 1–4 per side, veins (3 or)4 or 5(–7) per side; flowers (10–)12–22 mm diam.; stamens 5 or 10(–20), anthers white to ivory, pink, or purple, sometimes puce; bark on younger 2–5 cm thick branches usually dark gray-brown or orange, conspicuous horizontal lenticels absent > 2
2 Stamens 10, anthers pink or pink-purple to purple; flowers 14–18 mm diam.; thorns on twigs slender. Crataegus ser. Cerrones
2 Stamens 10(–20), anthers pink or ivory to white, sometimes puce; flowers (10–)12–18(–22) mm diam.; thorns on twigs usually ± stout, sometimes slender > 3
3 Thorns 2–5(–7) cm, slender to stout; inflorescence branches usually sparsely villous, sometimes glabrate; sepal margins denticulate to finely, sometimes strongly, glandular-serrate; pomes bright red to purple (late Aug), reddish purple to deep purple, often nearly black (late Sep), sepals conspicuous unless eroded, usually erect-patent, sometimes ± reflexed, usually accrescent (except in C. williamsii). 64c.Crataegus ser. Purpureofructus
3 Thorns 1–3.5 cm, ± stout; inflorescence branches glabrous or pubescent; sepal margins subentire, finely glandular distally; pomes black or dark purple mature, sepals short, reflexed or patent-recurved, not accrescent. 64c.Crataegus ser. Douglasianae
... more about "Crataegus sect. Douglasia"
0.8 cm8 mm <br />0.008 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
white +  and ivory pink or purple +
James B. Phipps +
Loudon +
exfoliating +  and plated +
compound +  and simple +
opposite +  and alternate +
8 cm80 mm <br />0.08 m <br /> (12 cm120 mm <br />0.12 m <br />) +
suborbiculate +, oblanceolate +, obovate +, less rhombic +  and more or less elliptic elliptic-oblong or ovate-rhombic +
3 cm30 mm <br />0.03 m <br /> (8 cm80 mm <br />0.08 m <br />) +
pubescent +  and glabrous +
adnate +  and distinct +
crowded +, scattered +  and alternate +
w +  and nc 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 +
obscure +  and evident +
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 +
red +  and purple or black reddish purple +
Arbor. Frutic. Brit. +
not arillate +
persistent +
free +  and distinct +
appressed +  and erect +
triangular +
1-50-flowered +  and few-leaved +
shallow +  and deep +
free +  and distinct +
branched +  and simple +
persistent +
distinct +
exsert +  and lateral +
elongate +
glabrous +  and tomentose +
Crataegus sect. Douglasia +
Crataegus +
section +
6 cm60 mm <br />0.06 m <br /> (10 cm100 mm <br />0.1 m <br />) +
straight +
slender +  and stout +
1 cm10 mm <br />0.01 m <br /> (6 cm60 mm <br />0.06 m <br />) +
craspedodromous +  and gland-tipped +
inconspicuous +
1 +  and few +
determinate +
4 +  and 9 +
tree +  and shrub +