Foliar trichomes of &lt;i&gt;Croton&lt;/i&gt; L. (Euphorbiaceae: Crotonoideae) from China and its taxonomic implications

Huan-Fang Liu,Jing-Ping Liao,Yun-Fei Deng

doi:10.3329/bjpt.v20i1.15468

Foliar trichomes of <i>Croton</i> L. (Euphorbiaceae: Crotonoideae) from China and its taxonomic implications

Huan-Fang Liu, Jing-Ping Liao + Show 1 more

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https://doi.org/10.3329/bjpt.v20i1.15468

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Abstract

Foliar trichomes of 21 species of the genus Croton L. from China have been examined using stereomicroscopy and scanning electron microscopy. Five trichome types characterized by their morphology are identified, viz., stellate, lepidote, simple, dendritic and appressed-rosulate. Only stellate trichome is observed in most species, with only six species that are found to maintain two or three trichome types. Trichome types and density are useful for species identification and sectional classification for Chinese species. Based on the trichome types and other morphological characters, 21 Chinese species are proposed to be placed in five sections. Croton crassifolius belongs to sect. Andrichnia; C. cascarilloides belongs to sect. Monguia; C. mangelong, C. kongensis, C. laevigatus and C. laniflorus belong to sect. Argyrocroton; C. lauioides, C. howii and C. damayeshu belong to sect. Adenophylli. The remaining Chinese Croton species might be placed into sect. Croton. A key for Chinese Croton species based on trichome morphology is provided.DOI: http://dx.doi.org/10.3329/bjpt.v20i1.15468Bangladesh J. Plant Taxon. 20(1): 85-94, 2013 (June)

Highlights

Croton L. (Euphorbiaceae s.s.) is one of the largest genera of flowering plants, with about1300 species of herbs, shrubs, trees and occasionally lianas that are ecologically prominent and important elements of secondary vegetation in the tropical and subtropical regions worldwide (Webster, 1993; Radcliffe-Smith, 2001)
Berry et al (2005) presented a molecular systematic analysis of the genus Croton and tribe Crotoneae using nrITS and trnL-trnF DNA sequences data to test the validity of Webster’s classification. van Ee et al (2011) revised the infrageneric classification and proposed a new system for New World Croton dividing into four subgenera and 31 sections including some species described as new ones
Foliar trichomes of 21 Chinese Croton can be separated into five types; stellate, lepidote, simple, dendritic and appressed-rosulate

Summary

Introduction

1300 species of herbs, shrubs, trees and occasionally lianas that are ecologically prominent and important elements of secondary vegetation in the tropical and subtropical regions worldwide (Webster, 1993; Radcliffe-Smith, 2001). Webster (1993) established the most recent infrageneric classification, recognizing 40 sections in the genus mainly based on the New World taxa. Berry et al (2005) presented a molecular systematic analysis of the genus Croton and tribe Crotoneae using nrITS and trnL-trnF DNA sequences data to test the validity of Webster’s classification. van Ee et al (2011) revised the infrageneric classification and proposed a new system for New World Croton dividing into four subgenera and 31 sections including some species described as new ones Berry et al (2005) presented a molecular systematic analysis of the genus Croton and tribe Crotoneae using nrITS and trnL-trnF DNA sequences data to test the validity of Webster’s classification. van Ee et al (2011) revised the infrageneric classification and proposed a new system for New World Croton dividing into four subgenera and 31 sections including some species described as new ones

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