244 POMACEAE. {Vor, II. 
12. Crataegus tomentosa 1. Pear- 
thorn. Pear Haw. (Fig. 2002.) 
Crataegus tomentosa I,. Sp. Pl. 476. 1753. 
A shrub or small tree, sometimes reaching 25° 
in height and a trunk diameter of 18’. Spines 
stout, 1/-234’ long; leaves petioled, broadly oval 
or ovate-oval, acute or acutish at the apex, nar- 
rowed or cuneate at the base, sharply dentate or 
somewhat lobed, not glandular, slightly scabrous 
above; pubescent, especially along the veins 
beneath, 2’-5’ long; corymbs many-flowered; 
twigs, petioles and calyx tomentose-pubescent; 
flowers about 6’’ broad; calyx-lobes lanceolate, 
usually incised; styles 3-5; fruit dull red, obovoid 
or globose, about 6’’ in diameter. 
In thickets, southern Ontario to New Jersey and 
Georgia, west to Michigan and Missouri. Wood 
hard, reddish-brown; weight per cubic foot 47 lbs. 
May-June. 
13. Crataegus flava Ait. Summer or Yellow Haw. (Fig. 2003.) 
Mespilus hyemalis Walt. F\. Car. 148. 1788? 
Crataegus flava Ait. Hort. Kew. 2: 169. 1789. 
C. flava var. pubescens A. Gray, Man. Ed. 5, 160. 1867. 
Crataegus flexispina Sarg. Gard. & For. 2: 424. 1889. 
Not Mespilus flexispina Muench. 1785. 
A tree, with maximum height of about 20° and 
trunk diameter of 10’, usually very thorny. 
Leaves obovate, petioled, obtuse or short-pointed 
and irregularly glandular dentate at the apex, nar- 
rowed or cuneate and often entire at the base, %4/- 
1%4/ long, pubescent on both sides or at length 
glabrate; corymbs few-flowered; pedicels and 
calyx pubescent; flowers 6//-9’’ broad; calyx- 
lobes entire or glandular-serrate; styles commonly 
5; fruit globose or somewhat pyriform, greenish, 
yellow or red, 5//-8’’ in diameter. 
In sandy thickets, Virginia to Florida, west to Mis- 
souri and Texas. April-May. 
14. Crataegus uniflora Muench. Dwarf Thorn. (Fig. 2004.) 
Crataegus uniflora Muench. Hausv. 5:147. 1770. 
Crataegus parvifolia Ait. Hort. Kew. 2: 169. 1789. 
Crataegus tomentosa Michx. F1. Bor, Am. 1: 289. 1803. 
Not L. 1753. 
A shrub, 3°-8° high or sometimes a small tree. 
Spines numerous, slender, 1/-2’ long; leaves ob- 
ovate, coriaceous, nearly sessile, obtuse and crenate 
at the apex, cuneate and entire at the base, 14/-14’ 
long, more or less pubescent on both surfaces or 
glabrate and at length shining above; corymbs I-7- 
flowered; twigs, pedicels and calyx pubescent; flow- 
ers 4//-5/’ broad; calyx-lobes lanceolate, deeply in- 
cised, glandular, about equaling the petals; styles 
commonly 5; fruit globose or pyriform, 5’/-8’” in 
diameter, yellow. 
In sandy soil, southern New York to Florida, west to 
West Virginia end Louisiana. April—May. 
