Rhodotypos

Siebold & Zuccarini

Fl. Jap. 1: 185, plate 99. 1841.

Common names: Black jetbead
Introduced
Etymology: Greek rhodon, rose, and typos, pattern, alluding to resemblance to genus Rosa
Treatment appears in FNA Volume 9. Treatment on page 386. Mentioned on page 387.

Shrubs, spreading, rounded, 5–20 (–30) dm. Stems 5–20+, widely arcuate; bark gray; long-shoots moderately branched; unarmed; glabrous. Leaves deciduous, cauline, opposite; stipules deciduous, linear, margins entire; petiole present; blade ovate, 4.5–10 cm, membranous, margins flat, sharply doubly serrulate, teeth sometimes stipitate-glandular along distal margins, surfaces sparsely sericeous. Inflorescences terminal on vernal, leaf-bearing branches, flowers solitary; bracts absent. Pedicels present. Flowers 30–45 mm diam.; epicalyx bractlets 4, slender; hypanthium shallowly cupped, 4–6 mm diam., exterior sericeous-strigose; sepals 4, spreading, ovate to oblong-ovate; petals 4, spreading-ascending, white, ovate-orbiculate, base short-clawed, apex rounded; stamens 30–60 (± in 4 clusters), much shorter than petals; torus thickened, dome-shaped, surrounding and overtopping ovaries, constricted below styles, leaving styles free, distally crenulate or 4-toothed; carpels 4, glabrous, styles lateral; ovules 2. Fruits aggregated nutlets (appearing as dry drupelets), 1–4, black, ovoid-globose, compressed, 6–9 mm; exocarp thin; mesocarp dry, thin; endocarp thick, cartilaginous; hypanthium persistent; sepals persistent, reflexed. x = 9.

Distribution

Introduced; e Asia

Discussion

Species 1.

Rhodotypos is an Asian mesophytic shrub that shares several characteristics with the western North American desert shrub Coleogyne, including opposite leaves, 4-merous, terminal, solitary flowers, ovaries with lateral (adaxial) styles, and a distinctive inner, rimlike or sheathlike torus extension that surrounds the ovaries and occasionally bears some of the stamens. The fruit of Rhodotypos is drupelike during development, but dries at maturity while retaining a shiny, smooth exocarp; it can be considered a modified drupelet.

With Coleogyne, Kerria and Neviusia, they form Kerrieae of subfam. Amygdaloideae, an alliance recognized by G. K. W. Schulze-Menz (1964) but in the Rosoideae.

Selected References

None.

... more about "Rhodotypos"
James Henrickson +
Siebold & Zuccarini +
compound +  and simple +
opposite +  and alternate +
short-clawed +
4.5 cm45 mm <br />0.045 m <br /> (10 cm100 mm <br />0.1 m <br />) +
free +  and distinct +
Black jetbead +
not +  and aggregated +
Greek rhodon, rose, and typos, pattern, alluding to resemblance to genus Rosa +
sericeous-strigose +
3 cm30 mm <br />0.03 m <br /> (4.5 cm45 mm <br />0.045 m <br />) +
unisexual +  and bisexual +
not +  and aggregated +
compressed +  and ovoid-globose +
0.6 cm6 mm <br />0.006 m <br /> (0.9 cm9 mm <br />0.009 m <br />) +
not +  and aggregated +
not +  and aggregated +
0.4 cm4 mm <br />0.004 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
crassinucellate +
opposite +  and alternate +
deciduous +
unarmed +  and branched +
serrulate +  and entire +
toothed +, unlobed +  and lobed +
inferior +  and superior +
biseriate +  and clustered +
collateral +  and marginal +
0 (?) +  and 4 (?) +
free +  and distinct +
spreading-ascending +
adnate +, free +, connate +  and distinct +
not arillate +
persistent +
free +  and distinct +
reflexed +  and spreading +
ovate +  and oblong-ovate +
tubelike +
Introduced +
free +  and distinct +
branched +  and simple +
5 +  and 20 +
persistent +
distinct +
not elongate +
Rhodotypos +
Rosaceae tribe Kerrieae +
stipitate-glandular +
inconspicuous +
4-toothed +, crenulate +  and dome--shaped +
constricted +