View source for Corylus

{{Treatment/ID
|accepted_name=Corylus
|accepted_authority=Linnaeus
|publications={{Treatment/Publication
|title=Sp. Pl.
|place=2: 998. 175
}}, {{Treatment/Publication
|title=Gen. Pl. ed.
|place=5, 433. 1754
|year=1754
}}
|common_names=Hazel
|basionyms=
|synonyms=
|hierarchy=Betulaceae;Betulaceae subfam. Coryloideae;Corylus
|hierarchy_nav=<div class="higher-taxa"><div class="higher-taxon"><small>family</small>[[Betulaceae]]</div><div class="higher-taxon"><small>subfamily</small>[[Betulaceae subfam. Coryloideae]]</div><div class="higher-taxon"><small>genus</small>[[Corylus]]</div></div>
|etymology=Latin corylus, hazel, from Greek korus, helmet, for shape and hardness of nut shells
|volume=Volume 3
|mention_page=
|treatment_page=
}}<!--

--><span class="statement" id="st-undefined" data-properties=""><b>Shrubs </b>and trees, 3–15 m; tree trunks usually 1, branching mostly deliquescent, trunks and branches terete. <b>Bark</b> grayish brown, thin, smooth, close, breaking into vertical strips and scales in age; prominent lenticels absent. <b>Wood</b> nearly white to light brown, moderately hard, heavy, texture fine. <b>Branches</b>, branchlets, and twigs nearly 2-ranked to diffuse; young twigs differentiated into long and short shoots. <b>Winter</b> buds sessile, broadly ovoid, apex acute; scales several, imbricate, smooth. <b>Leaves</b> on long and short shoots, 2-ranked. <b>Leaf</b> blade broadly ovate with 8 or fewer pairs of lateral veins, 4–12 × 3.5–12 cm, thin, bases often cordate, margins doubly serrate, apex occasionally nearly lobed; surfaces abaxially usually pubescent, sometimes glandular. <b>Inflorescences</b>: staminate catkins on short shoots lateral on branchlets, in numerous racemose clusters, formed previous growing season and exposed during winter, expanding well before leaves; pistillate catkins distal to staminate catkins, in small clusters of flowers and bracts, reduced, only styles protruding from buds containing them at anthesis, expanding at same time as staminate. <b>Staminate</b> flowers in catkins 3 per scale, congested; stamens 4, divided nearly to base to form 8 half-stamens; filaments very short, adnate with 2 bractlets to bract. <b>Pistillate</b> flowers 2 per bract. <b>Infructescences</b> compact clusters of several fruits, each subtended and surrounded by involucre of bracts, bracts 2, hairy [spiny], expanded, foliaceous, sometimes connate into short to elongate tube. <b>Fruits</b> relatively thin-walled nuts, nearly globose to ovoid, somewhat laterally compressed, longitudinally ribbed. <b>x</b> = 11.</span><!--

-->{{Treatment/Body
|distribution=Throughout north temperate zone;North America;Europe;Asia.
|discussion=<p>Species ca. 15 (3 in the flora).</p><!--
--><p><i>Corylus</i> differs from other <i>Betulaceae</i> in various features, most notably in the infructescences, which consist of small clusters of well-developed nuts, each enclosed by a loose involucre of leaflike bracts. As in <i>Ostrya</i>, the staminate catkins are formed during the summer and are exposed through the winter prior to anthesis. In <i>Corylus</i>, however, pistillate catkins develop at the same time as the staminate, and they consist of only a few flowers, protected by the scales of special buds rather than being arranged in elongate pistillate catkins. The staminate flowers are unique in the family in that well-developed sepals are occasionally present, clearly defining the three individual flowers that make up each cymule.</p><!--
--><p>A longstanding disparity occurs in the literature regarding the diploid chromosome number found in <i>Corylus</i> species, with both 2n = 22 and 2n = 28 being cited. J. G. Packer (pers. comm.) believes that the 2n = 28 for several species (R. H. Woodworth 1929c) was in error because of a misinterpretation of Woodworth's meiotic preparations, a number of which actually indicate eleven haploid chromosomes. Woodworth's count may be largely, if not entirely responsible for the persistence of this number in the literature.</p><!--
--><p>The genus consists of three major subgroups, the first composed of shrubby plants having a short, open involucre of two bracts surrounding the fruits (<i>Corylus</i> sect. <i>Corylus</i>). Members of <i>Corylus</i> sect. Tuboavellana Spach are of similar habit but have the involucre modified into a tubular beak, and <i>Corylus</i> sect. Acanthochlamnys Spach is characterized by densely spiny bracts. Recent treatments have avoided applying sectional names. The genus as a whole should be considered for taxonomic revision.</p><!--
--><p><i>Corylus</i> is the source of hazelnuts and filberts. Commercial filberts (C. colurna Linnaeus and <i>C. maxima</i> Miller) are cultivated in various parts of the world, particularly Turkey, Italy, Spain, China, and the United States. Wild hazelnuts (<i>C. americana</i> and <i>C. cornuta</i>) are smaller but similar in flavor to those of the cultivated species.</p>
|tables=
|references={{Treatment/Reference
|id=drumke1965a
|text=Drumke, J. S. 1965. A systematic survey of Corylus in North America. Diss. Abstr. 25: 4925--4926.
}}{{Treatment/Reference
|id=kasapligil1964a
|text=Kasapligil, B. 1964. A contribution to the histotaxonomy of Corylus (Betulaceae). Adansonia, n. s. 4: 43--90.
}}{{Treatment/Reference
|id=rose1895a
|text=Rose, J. N. 1895. Notes upon Corylus rostrata and C. californica. Gard. & Forest 8: 263.
}}{{Treatment/Reference
|id=wiegand1909a
|text=Wiegand, K. M. 1909. Recognition of Corylus rostrata and Corylus americana. Rhodora 11: 107.
}}
}}<!--

--><div class="treatment-key">
==Key==
<div class="treatment-key-group">
  
{| class="wikitable fna-keytable"
|-id=key-0-1
|1
|Fruit surrounded by soft bristly involucre connate to summit into narrow tube 2–5 times length of fruit; branchlets and petioles glabrous to pubescent, with or without glandular hairs.
|[[Corylus cornuta|Corylus cornuta]]
|-id=key-0-1
|1
|Fruit surrounded by involucre of 2 downy, expanded, foliaceous bracts, distinct nearly to base; branchlets and petioles covered with bristly glandular hairs.
|[[#key-0-2| > 2]]
|-id=key-0-2
|2
|Involucre slightly longer than to 2 times length of fruit; staminate catkins mostly in groups of 1–2, peduncles 5 mm or shorter; slender native shrubs to ca. 3 m.
|[[Corylus americana|Corylus americana]]
|-id=key-0-2
|2
|Involucre shorter than to only slightly longer than fruit; staminate catkins mostly in groups of 2–4, peduncles more than 5 mm; broad, spreading, introduced shrubs to ca. 5 m.
|[[Corylus avellana|Corylus avellana]]
|}
</div></div><!--

-->{{#Taxon:
name=Corylus
|authority=Linnaeus
|rank=genus
|parent rank=subfamily
|synonyms=
|basionyms=
|family=Betulaceae
|distribution=Throughout north temperate zone;North America;Europe;Asia.
|reference=drumke1965a;kasapligil1964a;rose1895a;wiegand1909a
|publication title=Sp. Pl.;Gen. Pl. ed.
|publication year=;1754
|special status=
|source xml=https://bitbucket.org/aafc-mbb/fna-data-curation/src/2e0870ddd59836b60bcf96646a41e87ea5a5943a/coarse_grained_fna_xml/V3/V3_322.xml
|subfamily=Betulaceae subfam. Coryloideae
|genus=Corylus
}}<!--

-->[[Category:Treatment]][[Category:Betulaceae subfam. Coryloideae]]