Crataegus rivularis |
Crataegus flava |
|
---|---|---|
mountain river hawthorn, river hawthorn |
yellow hawthorn, yellowleaf hawthorn |
|
Habit | Shrubs or trees, 30–50 dm. | Shrubs or trees, 50–60 dm. |
Stems | twigs: new growth greenish, sparsely pubescent, early glabrescent, 1–2-years old often red-purple; bark on younger 2–5 cm thick branches dark gray-brown, sometimes copper-colored; thorns on twigs straight or ± recurved, 2-years old black or purple-black, glossy, fine, 1.5–4 cm. |
twigs straight or slightly flexuous, new growth color not recorded, glabrous, 1-year old purple-brown, older dark gray; thorns on twigs straight to slightly recurved, 2-years old purple-brown, slender, 2–3 cm. |
Leaves | petiole 1–2.5 cm, glabrous; blade elliptic to narrowly elliptic, 3–8 cm, length 2+ times width, thin, base cuneate, lobes 0 or small apiculi at ends of some vein tips, margins serrate, teeth numerous, usually acute, fine to coarse, venation semicamptodromous, veins 4 or 5 per side, larger often branched proximal to ends, apex acute, abaxial surface glabrous, adaxial appressed-strigose young. |
petiole 1 mm wide, length 30–45% blade, winged distally, slightly pubescent, glandular; blade rhombic-obovate, 5–8 cm (in type material), base cuneate, lobes 1–3 per side, sinuous, sinuses shallow, lobe apex obtuse to acute, margins crenate to crenate-serrate, teeth gland-tipped, veins 3 or 4 per side, apex subacute to obtuse, adaxial surface pubescent young, glabrescent. |
Inflorescences | 6–12-flowered; branches glandular-punctate; bracteoles early caducous, usually present, margins sessile-glandular. |
4–6-flowered; branches glabrous or sparsely villous; bracteole margins glandular. |
Flowers | 14–17 mm diam.; sepals broadly deltate, 6–8 mm, margins entire, apex narrow, glabrous; stamens 10, anthers pink, sometimes ivory; styles 3–5. |
16–18 mm diam.; hypanthium glabrous; sepals 4–5 mm, margins glandular; stamens 13–16, anthers purple; styles 3–5. |
Pomes | deep red (mid Aug), black or blackish purple mature, suborbicular, 10 mm diam.; sepals ± erect to strongly outcurved or ± patent, 2–3 mm; pyrenes 3 or 4, sides eroded. |
dull orange, ± pyriform-oblong, 8–12 mm diam., glabrous; sepals on collar, ± reflexed; pyrenes 3–5. |
Crataegus rivularis |
Crataegus flava |
|
Phenology | Flowering mid May–early Jun; fruiting Aug–Sep. | Flowering early Apr; fruiting Sep–Oct. |
Habitat | Intermontane streamsides, ditches, flood plains | Deep, sandy soil |
Elevation | 1300–2300 m (4300–7500 ft) | 10–100 m (0–300 ft) |
Distribution |
AZ; CO; ID; NM; NV; UT; WY
|
FL; GA; SC
|
Discussion | Crataegus rivularis is most abundant in intermontane Colorado and Utah and is one of two hawthorns found in Arizona; it is rare in Nevada. There are reports from northwestern Texas (for example, D. S. Correll and M. C. Johnston 1970); they have not been verified. Crataegus rivularis is one of the more common woody species of mesic, valley bottom intermontane habitats. The species flowers early. Crataegus rivularis is superficially similar to the more or less sympatric, less common, C. saligna; it has larger leaves with fewer veins, larger flowers with ten stamens, and larger pomes. It differs from C. erythropoda little other than in leaf shape and ripe fruit color. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Of conservation concern. Crataegus flava ranges from southeastern Georgia to South Carolina and northern Florida. Wild specimens of the typical form have not been seen since the early 1900s; vegetative specimens resembling this species were collected from the Florida panhandle in the early part of the present century. Crataegus flava has been widely confused with members of both ser. Apricae and ser. Lacrimatae (J. B. Phipps et al. 2007). Its stamen number has been wrongly credited as 10 or 20; stamen number in the type has recently been verified as 13–16 by S. Landrein (Kew). Recent collections with 13–16 stamens are unknown. The correct stamen counts are unusual for Crataegus, which are mainly narrowly dispersed around modes of 10 or 20, so this perhaps suggests, together with its somewhat flexuous twigs, and rarity, hybrid origin. Crataegus flava is similar to C. rubella, particularly in fruit shape and color as well as general glandularity, so its placement with members of sect. Intricatae seems appropriate. Lack of recent collections similar to the type suggests that modern attributions to C. flava may represent hybrids involving members of ser. Apricae. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 9, p. 510. | FNA vol. 9, p. 588. |
Parent taxa | Rosaceae > subfam. Amygdaloideae > tribe Maleae > Crataegus > sect. Douglasia > ser. Cerrones | Rosaceae > subfam. Amygdaloideae > tribe Maleae > Crataegus > sect. Coccineae > ser. Intricatae |
Sibling taxa | ||
Name authority | Nuttall: in J. Torrey and A. Gray, Fl. N. Amer. 1: 464. (1840) | Aiton: Hort. Kew. 2: 169. (1789) |
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