View source for Rhamnus

{{Treatment/ID
|accepted_name=Rhamnus
|accepted_authority=Linnaeus
|publications={{Treatment/Publication
|title=Sp. Pl.
|place=1: 193. 1753
|year=1753
}}
|common_names=Buckthorn;nerprun
|basionyms=
|synonyms=
|hierarchy=Rhamnaceae;Rhamnus
|hierarchy_nav=<div class="higher-taxa"><div class="higher-taxon"><small>family</small>[[Rhamnaceae]]</div><div class="higher-taxon"><small>genus</small>[[Rhamnus]]</div></div>
|etymology=Greek rhamnos, prickly shrubs, such as buckthorn
|volume=Volume 12
|mention_page=page 43, 44, 46, 51, 52, 62, 70
|treatment_page=page 45
}}<!--

--><span class="statement" id="st-undefined" data-properties=""><b>Shrubs </b>or trees, erect or spreading, unarmed or armed with thorns; bud scales present, buds glabrate. <b>Leaves</b> deciduous or persistent, present at flowering, alternate or opposite to subopposite, sometimes fascicled on short shoots; blade not gland-dotted; pinnately veined, secondary veins arching, not parallel. <b>Inflorescences</b> axillary, within foliage, fascicles or cymes, or flowers solitary; peduncles and pedicels not fleshy in fruit. <b>Pedicels</b> present. <b>Flowers</b> usually unisexual, rarely some bisexual (plants polygamous); hypanthium campanulate to cupulate, 2–3 mm wide, usually not circumscissile, rarely so at or just proximal to sepal bases; sepals 4–5, spreading, yellowish, yellowish green, green, or greenish white to white, ovate-triangular, thin, not keeled or crested adaxially; petals 0 or 4[–5], yellowish to cream, hooded, spatulate, not clawed; nectary thin, lining hypanthium; stamens 4–5, (rudimentary in pistillate flowers); ovary superior, 2–4-locular; styles 2–4, connate proximally. <b>Fruits</b> drupes; stones 2–4, longitudinally dehiscent. <b>Seeds</b> obovoid or oblong-obovoid, not beaked, longitudinally furrowed. <b>x</b> = 12.</span><!--

-->{{Treatment/Body
|distribution=North America;Mexico;Central America;South America;Europe;e Asia;Africa.
|discussion=<p>Species ca. 150 (14 in the flora).</p><!--
--><p><i>Rhamnus</i> in the flora area includes six species (species 9–14) introduced primarily from Europe and Asia. The native species for the most part are clearly delimited, but the <i>R. crocea</i> complex needs taxonomic study using modern techniques.</p>
|tables=
|references={{Treatment/Reference
|id=johnston1975a
|text=Johnston, L. A. 1975. Revision of the Rhamnus serrata complex. Sida 6: 67–79.
}}{{Treatment/Reference
|id=wolf1938a
|text=Wolf, C. B. 1938. The North American species of Rhamnus. Rancho Santa Ana Bot. Gard. Monogr., Bot. Ser. 1.
}}
}}<!--

--><div class="treatment-key">
==Key==
<div class="treatment-key-group">
  
{| class="wikitable fna-keytable"
|-id=key-0-1
|1
|Leaves persistent, alternate, blades distinctly coriaceous; petals 0 (rarely 4 in R. pilosa).
|[[#key-0-2| > 2]]
|-id=key-0-2
|2
|Leaf blade secondary veins with basal pair diverging much more acutely than distal pairs; inflorescences cymes or flowers solitary; sepals 5; drupes dark red, becoming black, stones 3.
|[[Rhamnus alaternus|Rhamnus alaternus]]
|-id=key-0-2
|2
|Leaf blade secondary veins all diverging at nearly same angle; inflorescences fascicles or flowers solitary; sepals 4(–5); drupes red, stones 2.
|[[#key-0-3| > 3]]
|-id=key-0-3
|3
|Leaf blade margins entire or coarsely serrate, blunt-serrate, or spinulose-serrate.
|[[#key-0-4| > 4]]
|-id=key-0-4
|4
|Shrubs, 1.2–2(–4) m, usually armed with thorns; leaf blades 0.7–2 cm, elliptic to obovate or ovate; California mainland.
|[[Rhamnus crocea|Rhamnus crocea]]
|-id=key-0-4
|4
|Shrubs or trees, 2.5–6(–10) m, unarmed; leaf blades (1.5–)2–5(–6) cm, broadly elliptic to oblong or ovate-oblong; California Channel Islands.
|[[Rhamnus pirifolia|Rhamnus pirifolia]]
|-id=key-0-3
|3
|Leaf blade margins spinulose to spinose-dentate.
|[[#key-0-5| > 5]]
|-id=key-0-5
|5
|Branchlets stiff, glabrous or densely and softly hirtellous; both leaf blade surfaces glabrous.
|[[Rhamnus ilicifolia|Rhamnus ilicifolia]]
|-id=key-0-5
|5
|Branchlets flexible, sparsely to densely softly hirtellous; both leaf blade surfaces sparsely to densely softly hirtellous.
|[[Rhamnus pilosa|Rhamnus pilosa]]
|-id=key-0-1
|1
|Leaves deciduous, alternate, subopposite, or opposite, sometimes fascicled on short shoots, blades herbaceous to subcoriaceous; petals 0 or 4.
|[[#key-0-6| > 6]]
|-id=key-0-6
|6
|Leaves usually alternate, sometimes subopposite, blade secondary veins 4–11 pairs; shrubs or small trees 0.5–3(–4) m, unarmed.
|[[#key-0-7| > 7]]
|-id=key-0-7
|7
|Sepals 5; petals 0; drupe stones 3; shrubs 0.5–1(–1.5) m; wetlands and seeps.
|[[Rhamnus alnifolia|Rhamnus alnifolia]]
|-id=key-0-7
|7
|Sepals 4; petals 4; drupe stones 2 (3 in R. arguta); shrubs or small trees 0.5–3(–4) m; drier habitats.
|[[#key-0-8| > 8]]
|-id=key-0-8
|8
|Petioles 10–28 mm; pedicels 10–24(–30) mm; drupe stones 3; leaf blades usually broadly ovate, ovate, oblong-ovate, or ovate-cordate, sometimes ovate-orbiculate, margins spinulose-serrate.
|[[Rhamnus arguta|Rhamnus arguta]]
|-id=key-0-8
|8
|Petioles 3–8 mm; pedicels (0–)0.5–4 mm; drupe stones 2; leaf blades lanceolate, elliptic-lanceolate, oblong-lanceolate, elliptic, or elliptic-oblong, margins crenulate, crenulate-serrate, or serrulate.
|[[#key-0-9| > 9]]
|-id=key-0-9
|9
|Branchlets 6+ cm; leaf blade apices acute to acuminate; c, e United States.
|[[Rhamnus lanceolata|Rhamnus lanceolata]]
|-id=key-0-9
|9
|Branchlets 2–5 cm; leaf blade apices acute to obtuse or rounded; w United States.
|[[#key-0-10| > 10]]
|-id=key-0-10
|10
|Bud scales thin, glossy, pale golden to yellowish; leaf blades usually lanceolate, sometimes elliptic-lanceolate or oblong-lanceolate, 3–8 cm, both surfaces glabrous.
|[[Rhamnus smithii|Rhamnus smithii]]
|-id=key-0-10
|10
|Bud scales coriaceous, dull, dark red to reddish brown; leaf blades usually elliptic to elliptic-lanceolate or elliptic-oblong, 1.5–5(–5.5) cm, both surfaces minutely hirtellous.
|[[Rhamnus serrata|Rhamnus serrata]]
|-id=key-0-6
|6
|Leaves usually opposite to subopposite, sometimes alternate or fascicled on short shoots, blade secondary veins 2–7(–8) pairs; shrubs or trees (1–)2–10 m, armed with thorns.
|[[#key-0-11| > 11]]
|-id=key-0-11
|11
|Leaf blade bases rounded to truncate or cordate; drupe stones 3–4.
|[[#key-0-12| > 12]]
|-id=key-0-12
|12
|Leaf blade margins crenate-serrate, secondary veins 2–4 pairs; pedicels 2–4 mm; drupes 5–6(–8) mm.
|[[Rhamnus cathartica|Rhamnus cathartica]]
|-id=key-0-12
|12
|Leaf blade margins spinulose-serrate, secondary veins (3–)4–5 pairs; pedicels 10–24(–30) mm; drupes 7–10 mm.
|[[Rhamnus arguta|Rhamnus arguta]]
|-id=key-0-11
|11
|Leaf blade bases cuneate or acute; drupe stones 2.
|[[#key-0-13| > 13]]
|-id=key-0-13
|13
|Leaf blades obovate to elliptic-oblanceolate or broadly oblanceolate, adaxial surfaces usually minutely hirtellous at least along main veins on distal 1/3, rarely glabrous.
|[[Rhamnus japonica|Rhamnus japonica]]
|-id=key-0-13
|13
|Leaf blades usually elliptic to oblong, oblong-obovate, obovate-elliptic, or oblong-lanceolate, sometimes ovate to obovate, rarely oblanceolate-elliptic, adaxial surfaces glabrous or sparsely pilose on veins.
|[[#key-0-14| > 14]]
|-id=key-0-14
|14
|Leaf blades green abaxially, abaxial surface with straight, colorless hairs on veins, secondary veins 3–5(–6) pairs; pedicels 10–20 mm.
|[[Rhamnus davurica|Rhamnus davurica]]
|-id=key-0-14
|14
|Leaf blades yellowish green abaxially, abaxial surface with wavy or curled, yellow hairs along veins or at least in vein axils, secondary veins (4–)5–7(–8) pairs; pedicels 5–10 mm.
|[[Rhamnus utilis|Rhamnus utilis]]
|}
</div></div><!--

-->{{#Taxon:
name=Rhamnus
|author=Guy L. Nesom;John O. Sawyer†
|authority=Linnaeus
|rank=genus
|parent rank=family
|synonyms=
|basionyms=
|family=Rhamnaceae
|distribution=North America;Mexico;Central America;South America;Europe;e Asia;Africa.
|reference=johnston1975a;wolf1938a
|publication title=Sp. Pl.
|publication year=1753
|special status=
|source xml=https://bitbucket.org/aafc-mbb/fna-data-curation/src/2e0870ddd59836b60bcf96646a41e87ea5a5943a/coarse_grained_fna_xml/V12/V12_820.xml
|genus=Rhamnus
}}<!--

-->[[Category:Treatment]][[Category:Rhamnaceae]]