Crataegus douglasii Lindl.
black hawthorn
Rosaceae (Rose family)

Introduction to Vascular Plants

Photograph

© Bryan Kelly-McArthur     (Photo ID #68847)


Map

E-Flora BC Static Map

Distribution of Crataegus douglasii
Click here to view the full interactive map and legend

Introduction

Black hawthorn is a medium to tall shrub species frequently found in southern British Columbia. It has white flowers with 5 petals that appear in the spring; alternate simple leaves, and straight, stout thorns.

View a key to the hawthorns of the Pacific Coast (from Alaska to California), and species notes, by Jim Phipps.

Species Information

General:
Medium to tall shrub 1-7 m tall, with stout, straight thorns 1-2 (3) cm long; bark grey or brownish, rough and scaly.
Leaves:
Alternate, deciduous, egg-shaped to oval, 3-6 cm long, irregularly toothed, the top end often with 5 to 9 shallow lobes, somewhat thick and leathery, dark green above, paler below, nearly smooth to hairy.
Flowers:
Inflorescences short, terminal or axillary clusters; flowers several to many, stalked, 1-1.5 cm across; corollas white, the petals 5, nearly circular, 4-7 mm long; calyces 5-lobed, the lobes triangular, somewhat long-hairy toward the tip; ovaries inferior, smooth to short-curly-hairy, the styles usually 5; stamens 10 to 20.
Fruits:
Berry-like pomes (like miniature apples), globe- to egg-shaped, about 1 cm long, blackish-purple, smooth; stones (nutlets) 2 to 5, 1-seeded.
Notes:
Two varieties occur in BC:

1. Flowers mostly with 10 stamens; ovaries often hairy; leaves often weakly lobed above the middle as well as saw-toothed; plants from largely east of the Coast-Cascade Mtns., the common variety................. var. douglasii

1. Flowers mostly with 20 stamens; ovaries usually smooth; leaves merely 1- to 2-times saw-toothed; plants from west of the Cascade Mtns........................ var. suksdorfii Sarg.

SourceThe Illustrated Flora of British Columbia

USDA Species Characteristics

Flower Colour:
White
Blooming Period:
Mid Spring
Fruit/Seed characteristics:
Colour: Black
Present from Spring to Fall
Source:  The USDA

Ecology

Ecological Framework for Crataegus douglasii

The table below shows the species-specific information calculated from
original data (BEC database) provided by the BC Ministry of Forests and Range.
(Updated August, 2013)

Site Information
Value / Class

Avg

Min

Max

Elevation (metres)
601 1 1188
Slope Gradient (%)
9 0 80

Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]

248 0 360
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
4 1 7
Modal Nutrient Regime
Class
D
# of field plots
 species was recorded in:
121
Modal BEC Zone Class
IDF

All BEC Zones (# of stations/zone) species was recorded in

BG(14), CDF(5), CWH(10), ICH(36), IDF(36), PP(9), SBS(8)

Habitat and Range

Moist to mesic, open rocky slopes, bluffs, streambanks, lakeshores, gullies, thickets, edges of forests in the lowland to montane zones; frequent in S BC north to 56o N; N to S AK, E to ON and S to SD, WY and CA.

SourceThe Illustrated Flora of British Columbia

Synonyms

Synonyms and Alternate Names:
Crataegus columbiana Howell
Crataegus douglasii var. douglasii Lindl. [superfluous autonym]