29. Crataegus viridis L. (green hawthorn)

C. davisii Sarg.

C. furcata Sarg.

C. lanceolata Sarg.

C. glabriuscula Sarg.

C. lutensis Sarg.

C. nitens Sarg.

C. ovata Sarg.

C. pechiana Sarg.

Pl. 531 a, b; Map 2440

Plants shrubs or trees, (2–)3–15 m tall. Bark thin, gray to dark gray, relatively smooth, mottled, peeling in large, irregular patches exposing lighter gray and orangish brown underlayers. Branchlets nearly unarmed or with scattered to relatively dense thorns, these(1–)2–4(–7) cm long, relatively slender, very dark brown to dark purplish brown or nearly black at second year, occasionally dark gray or with age. Petioles 0.7–2.5 cm long, glabrous or nearly so, nonglandular. Leaf blades 1.5–6.0(–8.0) cm long (rarely to 11 cm on extension shoots), narrowly elliptic to oblong elliptic, rhombic, or broadly ovate, tapered or less commonly narrowly angled at the base, (those of extension shoot leaves sometimes rounded), rounded to sharply pointed at the tip, unlobed or with 1–3 sharply (but sometimes broadly) pointed, but shallow lobes per side, the margins variously finely scalloped to coarsely and sharply but simply toothed, the largest teeth mostly 1–2 mm deep, papery to slightly leathery, the upper surface dull to less commonly somewhat shiny, the secondary veins usually 3–5 per side. Inflorescences 5–18(–30)-flowered, the branches usually glabrous, the bractlets usually relatively numerous, but shed early. Flowers 10–18 mm in diameter. Sepals glabrous. Petals 5–9 mm long. Stamens usually 20, the anthers ivory to cream-colored. Fruits 5–8 mm in diameter, orange to deep red, not glaucous. Diploid to triploid or higher (by flow cytometry; see Talent and Dickinson [2005]). Early April–late May.

Scattered in the state; uncommon to absent from most of the Glaciated Plains Division and the western and northern portions of the Ozarks (eastern U.S. west to Kansas and Texas). Bottomland forests, swamps, fens, marshes, margins of ponds, lakes, and sinkhole ponds, mesic upland forests, savannas, glades, edges of sand prairies, banks of streams and rivers, ledges, bases, and tops of bluffs; edges of pastures, margins of crop fields, fencerows, and roadsides.

Crataegus viridis is the most commonly encountered Missouri hawthorn at bottomland sites, however, the species also can occur in drier upland situations. Selected rust-resistant cultivars such as cv. ‘Winter King’ make excellent ornamentals. The best forms color well in the autumn and have attractive fruits. The fresh green foliage is attractive in the spring, against which the white flowers are well set off.

This is an extremely variable species in Missouri as to leaf size and shape, and to some extent fruit size. The bractlets of C. viridis are mostly nonglandular and are exceptionally narrow and shed very early. Forms with red anthers or hairy flower stalks, petioles, and leaves are very rare and may represent past hybridization with other hawthorn species. The major variants of C. viridis have been separated as varieties by some authors. In its main range, the most distinctive of these is var. glabriuscula, which is southwestern in its distribution and enters southern Missouri, where it becomes somewhat less distinct, intergrading somewhat with var. viridis. The other varieties all grade into one another and show no ecological segregation. Missouri specimens attributable to var. nitens were all collected in Marion County by the Rev. John Davis in the early 1900s. These plants possibly represent a hybrid, perhaps with C. pruinosa; their leaves are more leathery and fruits a little larger than those of the other varieties.The remaining varieties have been documented from both historical and modern collections. The following key is provided for those who wish to determine specimens below the species level.