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摘要： 樓梯草属植物的瘦果具有较高的形态多样性，可作为种类鉴定的重要依据。然而，中国超过半数楼梯草属植物缺少瘦果形态信息。该研究通过野外考察、标本查阅以及光镜和扫描电镜的观察，对七种楼梯草属植物的瘦果进行了补充描述，并提供了墨线图和照片。该研究结果对该属的进一步分类修订提供了有价值的信息。
关键词： 补充描述， 瘦果， 楼梯草属， 扫描电镜
Elatostema Forster & Forster comprises around 500 species of herbs， small shrubs and subshrubs （Wang， 2014） that grow in deep shade in forests， stream sides， gorges and caves. Elatostema is mainly distributed in tropical and subtropical regions of Africa， Asia and Oceania （Wang， 1995； Lin et al， 2003）. The latest revision for Chinese Elatostema was put forward by Wang （2014） that contained 280 species， of which 108 species were endemic.
Elatostema species are difficult to distinguish due to the tiny flowers， variation in staminate tepal number and the reduced nature of pistillate tepals which reduced the available number of characters for species delimitation （Fu et al， 2014）. The achene is one of important morphological characters in determining systematic position， evolutionary level and infragenetic relationship of Elatostema， as well as delimiting series （Wu et al， 2012； Wang， 2014）. Wang （2014） concluded ten types of achenes： （1） ribbed， （2） ribbed and puncticulate， （3） ribbed and tuberculate， （4） ribbed， tuberculate and winged， （5） tuberculate， （6） tuberculate and reticulatestriate， （7） smooth， （8） puncticulate， （9） lineolate and （10） lineolate and tuberculate. Despite the high morphological diversity of achene in this genus provides a useful character in delimitation， over half of Chinese species are lacking of achene information （Wang， 2014）.
In this paper， we aimed to supplement the description of achene based on our field collection and specimen checking by light microscope （LM） and scanning electron microscope （SEM） to provide valuable information for further taxonomic revision in this genus.
1 Materials and Methods
The mature achenes of seven species were carefully collected from specimen by tweezer for LM and SEM observation. For each species， 3-10 achenes were used to determine the size and shape. All the voucher specimens were deposited in the herbarium of Guangxi Institute of Botany （IBK）. The illustration for each species was also drawn based on LM and SEM photos.
For LM， achenes were examined under a XTZD binocular microscope and Plan Apo lens at × 20 magnifications. Photos were taken by Canon G12 camera.
For SEM， achenes were placed in a bathtype ultrasonic cleaner for 10 min with 70% ethanol to remove the impurity. After airdrying， the achenes were mounted on the stubs using doublesided adhesive tape and coated with gold in a sputter coater. The coated achenes were observed and photographed under ZEISSE VO18 scanning electron microscope. The achene size was measured on photo of SEM by the ImagePro Plus. The achene shape and surface were followed Liu et al （2004） and Wang （2014）. 2 Results and Discussion
2.1 Elatostema angulaticaule W. T. Wang & Y. G. Wei in Guihaia 29（6）： 716. 2009.
Achenes brownish， ellipsoid， 0.558-0.618 × 0.266-0.322 mm， length：width ratio 1.9-2.1：1， longitudinally 6ribbed （Fig. 1： A； Fig. 2： A； Fig. 3： A）.
Voucher specimen：
Guangxi： Xilin County， Guzhang， 7 June 2006， Y. G. Wei 06178 （IBK）.
Elatostema angulaticaule is the most similar to E. tenuifolium W. T. Wang （Wei & Wang， 2009）. The differences of achene between two species are that the former one has smaller size （0.558-0.618 × 0.266-0.322 mm vs. 1 × 0.6-0.8 mm） and surface with longitudinally 6ribbed （vs. longitudinally 6ribbed and sparsely tuberculate）.
2.2 Elatostema heterocladum W. T. Wang. A. K. Monro & Y. G. Wei in Phytotaxa 147（1）： 7. 2013.
Achenes brownish， ellipsoid， 0.790-0.985 × 0.412-0.499 mm， length：width ratio 1.8-2.3：1， longitudinally 4ribbed， and between each pair of ribs sparsely tuberculatepuncticulate （Fig. 1： B； Fig. 2： B； Fig. 3： B）.
Voucher specimen：
Guangxi：Longzhou County， Banbi， April 2011， Y. G. Wei & F. Wen 1176 （IBK）.
Elatostema heterocladum is the most similar to E. androstachyum W. T. Wang， A. K. Monro & Y. G. Wei （Wei et al， 2013）. The differences of achene between two species are that the former one is brownish （vs. beige）， has bigger size （0.790-0.985 × 0.412-0.499 Fig. 1Illustration of achenes of seven Elatostema speciesA. E. angulaticaule W. T. Wang & Y. G. Wei； B. E. heterocladum
W. T. Wang. A. K. Monro & Y. G. Wei； C. E. obscurinerve W. T. Wang； D. E. planinerve W. T. Wang & Y. G. Wei；
E. E. pseudolongipes W. T. Wang & Y. G. Wei； F. E. longibracteatum W. T. Wang； G. E. subtrichotomum
W. T. Wang. The same below. （Illustrated by LIN WenHong）
Fig. 2LM photos of achenes of seven Elatostema species
Fig. 3SEM photos of achenes of seven Elatostema species
mm vs. ca. 0.65 × 0.3 mm） and surface with longitudinally 4ribbed， and between each pair of ribs sparsely tuberculatepuncticulate （vs. 5 longitudinal ribs）.
2.3 Elatostema obscurinerve W. T. Wang in Bull. Bot. Lab. N. E. Forest. Inst. 7： 63. 1980.
Achenes brownish， ellipsoid， 0.550-0.741 × 0.283-0.355 mm， length： width ratio 1.9-2.1：1， longitudinally 6ribbed （Fig. 1： C； Fig. 2： C； Fig. 3： C）.
Voucher specimen：
Guangxi： Fengshan County， Yunfeng Cave， 27 April 2011， Y. G. Wei & F. Wen C005E1 （IBK）.
Elatostema obscurinerve is the most similar to E. involucratum Franch. et Sav. （Wang， 1980）. The differences of achene between two species are that the former one has smaller size （0.550-0.741 mm vs. 0.7-0.8 mm） and surface with longitudinally 6ribbed （vs. longitudinally 6ribbed and tuberculate）. 2.4 Elatostema planinerve W. T. Wang & Y. G. Wei in Nordic J. Bot. 30： 1. 2012.
Achenes brownish，ellipsoid， 0.552-0.566 × 0.297-0.331 mm， length：width ratio 1.7-1.8：1， longitudinally 6ribbed （Fig. 1： D； Fig. 2： D； Fig. 3： D）.
Voucher specimen：
Guizhou： Xingyi City，31 March 2010， Y. G. Wei & F. Wen 1027 （IBK）.
Elatostema planinerve is the most similar to E. bracteosum （Wen et al， 2012）. The differences of achene between two species are that the former one has smaller size （0.552-0.566 mm vs. 0.7-1 mm） and surface with longitudinally 6ribbed （vs. longitudinally 6ribbed and tuberculate）.
2.5 Elatostema pseudolongipes W. T. Wang & Y. G. Wei in Elatostema （Urticaeae） in China 279. 2014.
Achenes brownish， ellipsoid， 0.618-0.682 × 0.366-0.398 mm， length：width ratio 1.6-1.8：1， tuberculate （Fig. 1： E； Fig. 2： E； Fig. 3： E）.
Voucher specimen：
Guangxi： Longzhou County， Banbi， 21 May 2010， Y. G. Wei & A. K. Monro AM6813 （IBK）.
Elatostema pseudolongipes is the most similar to E. longipes W. T. Wang （Wang， 2014）. The differences of achene between two species are that the former one has smaller size （0.618-0.682 mm vs. ca. 0.8 mm） and surface with tuberculate （vs. longitudinally 6ribbed）.
2.6 Elatostema longibracteatum W. T. Wang in Bull. Bot. Res. Harbin 2（1）： 6. 1982.
Achenes brownish， ellipsoid， 0.540-0.687 × 0.243-0.293 mm， length：width ratio 2.0-2.5：1， longitudinally 68ribbed （Fig. 1： F； Fig. 2： F； Fig. 3： F）.
Voucher specimen：
Yunnan： Malipo County， Niuchang Village， 2 May 2013，L. F. Fu & S. L. Huang FL0020 （IBK）.
Elatostema longibracteatum is the most similar to E. asterocephalum W. T. Wang （Wang， 1982）. The differences of achene between two species are that the former one has smaller size （0.540-0.687 mm vs. 0.8 mm） and surface with longitudinally 68ribbed （vs. longitudinally 68ribbed and tuberculate）.
2.7 Elatostema subtrichotomum W. T. Wang in Bull. Bot. Lab. N. E. Forest. Inst. 7： 25. 1980.
Achenes brownish， ovoidellipsoid， 0.600-0.664 × 0.277-0.336 mm， length：width ratio 1.8.0-2.3：1， longitudinally 45ridded， between each pair of ribs sparsely tuberculate and two opposite rids winged （Fig. 1：G； Fig. 2： G； Fig. 3： G）.
Voucher specimen：
Guizhou： Guiyang City， Zijiang Difeng， 16 May 2012， Y. H. Tseng & L. F. Fu Zn1267 （IBK）.
Elatostema subtrichotomum is the most similar to E. oblongifolium Fu ex W. T. Wang （Wang， 1980）. The differences of achene between two species are that the former one has smaller size （0.600-0.664 mm vs. 0.8-0.9 mm） and surface with longitudinally 45ridded， between each pair of ribs sparsely tuberculate and two opposite rids winged （vs. longitudinally 6ribbed）. AcknowledgementsWe would like to thank LIN WenHong for the illustration and Dr. DONG LiNa for her constructive suggestions on the manuscript. We also thank the herbarium of Guangxi Institute of Botany （IBK） for checking specimens.
References：
FU LF， DO VT， WEN F， et al， 2014. Elatostema arcuatobracteatum （Urticaceae）， a new species from Vietnam [J]. Phytotaxa， 174（2）： 111-115.
LIN Q， FRIIS I， WILMOTDEAR MC， 2003. Elatostema [M]//WU ZY， RAVEN PH. Flora of China. Beijing： Science Press； St. Louis， Missouri： Missouri Botanical Garden Press， 5： 76-189.
LIU CJ， LIN Q， HE JX， 2004. Methods and terminology of study on seed morphology from China [J]. Acta Bot BorealOccident Sin， 24（1）： 178-188. [刘长江， 林祁， 贺建秀， 2004. 中国植物种子形态学研究方法和術语 [J]. 西北植物学报， 24（1）： 178-188.]
WANG WT， 1980. Classificatio specierum sinicarum Elatostematis （Urticaceae） [J]. Bull Bot Lab NE For Inst， 7： 1-96. [王文采， 1980. 中国荨麻科楼梯草属分类 [J]. 东北林学院植物研究室汇刊， 7： 1-96.]
WANG WT， 1982. Taxa Nova Pellioniae Elatostematisque E Sina [J]. Bull Bot Res， 2（1）： 1-31. [王文采， 1982. 赤车属和楼梯草属新分类群 [J]. 植物研究， 2（1）： 1-31.]
WANG WT， 1995. Elatostema [M]//WANG WT， CHEN CJ. Flora Reipubicae Popularis Sinicae. Beijing： Science Press， 23（2）： 187-317. [王文采， 1995. 楼梯草属 [M]//王文采， 陈家瑞. 中国植物志， 23（2）： 187-317.]
WANG WT， 2014.Elatostema （Urticaceae） in China [M]. Qingdao： Qingdao Press. [王文采， 2014. 中国楼梯草属植物 [M]. 青岛： 青岛出版社.]
WEI YG， MONRO AK， WANG WT， 2013. Additions to the flora of China： three new species of Elatostema （Urticaceae） from Guangxi [J]. Phytotaxa， 147（1）： 1-12.
WEI YG， WANG WT， 2009. Notes on Elatostema J.R. et G. Forst. （Urticaceae） from Guangxi [J]. Guihaia， 29（6）： 711-718. [韦毅刚， 王文采， 2009. 广西楼梯草属研究随记 [J]. 广西植物， 29（6）： 711-718.]
WEN F， FU LF， WEI YG， et al， 2013. Elatostema planinerve and E. longicuspe spp. nov. （Urticaceae） from Guizhou Province， China [J]. Nord J Bot， 31： 312-315.
WU ZY， WANG H， LI DZ， 2012. Supplementary description of achenes of seven species in Elatostema （Urticaceae） [J]. Guihaia， 32（5）： 603-606. [吴增源， 王红， 李德铢， 2012. 荨麻科楼梯草属七种植物果实的补充描述 [J]. 广西植物， 32（5）： 603-606.]
关键词： 补充描述， 瘦果， 楼梯草属， 扫描电镜
Elatostema Forster & Forster comprises around 500 species of herbs， small shrubs and subshrubs （Wang， 2014） that grow in deep shade in forests， stream sides， gorges and caves. Elatostema is mainly distributed in tropical and subtropical regions of Africa， Asia and Oceania （Wang， 1995； Lin et al， 2003）. The latest revision for Chinese Elatostema was put forward by Wang （2014） that contained 280 species， of which 108 species were endemic.
Elatostema species are difficult to distinguish due to the tiny flowers， variation in staminate tepal number and the reduced nature of pistillate tepals which reduced the available number of characters for species delimitation （Fu et al， 2014）. The achene is one of important morphological characters in determining systematic position， evolutionary level and infragenetic relationship of Elatostema， as well as delimiting series （Wu et al， 2012； Wang， 2014）. Wang （2014） concluded ten types of achenes： （1） ribbed， （2） ribbed and puncticulate， （3） ribbed and tuberculate， （4） ribbed， tuberculate and winged， （5） tuberculate， （6） tuberculate and reticulatestriate， （7） smooth， （8） puncticulate， （9） lineolate and （10） lineolate and tuberculate. Despite the high morphological diversity of achene in this genus provides a useful character in delimitation， over half of Chinese species are lacking of achene information （Wang， 2014）.
In this paper， we aimed to supplement the description of achene based on our field collection and specimen checking by light microscope （LM） and scanning electron microscope （SEM） to provide valuable information for further taxonomic revision in this genus.
1 Materials and Methods
The mature achenes of seven species were carefully collected from specimen by tweezer for LM and SEM observation. For each species， 3-10 achenes were used to determine the size and shape. All the voucher specimens were deposited in the herbarium of Guangxi Institute of Botany （IBK）. The illustration for each species was also drawn based on LM and SEM photos.
For LM， achenes were examined under a XTZD binocular microscope and Plan Apo lens at × 20 magnifications. Photos were taken by Canon G12 camera.
For SEM， achenes were placed in a bathtype ultrasonic cleaner for 10 min with 70% ethanol to remove the impurity. After airdrying， the achenes were mounted on the stubs using doublesided adhesive tape and coated with gold in a sputter coater. The coated achenes were observed and photographed under ZEISSE VO18 scanning electron microscope. The achene size was measured on photo of SEM by the ImagePro Plus. The achene shape and surface were followed Liu et al （2004） and Wang （2014）. 2 Results and Discussion
2.1 Elatostema angulaticaule W. T. Wang & Y. G. Wei in Guihaia 29（6）： 716. 2009.
Achenes brownish， ellipsoid， 0.558-0.618 × 0.266-0.322 mm， length：width ratio 1.9-2.1：1， longitudinally 6ribbed （Fig. 1： A； Fig. 2： A； Fig. 3： A）.
Voucher specimen：
Guangxi： Xilin County， Guzhang， 7 June 2006， Y. G. Wei 06178 （IBK）.
Elatostema angulaticaule is the most similar to E. tenuifolium W. T. Wang （Wei & Wang， 2009）. The differences of achene between two species are that the former one has smaller size （0.558-0.618 × 0.266-0.322 mm vs. 1 × 0.6-0.8 mm） and surface with longitudinally 6ribbed （vs. longitudinally 6ribbed and sparsely tuberculate）.
2.2 Elatostema heterocladum W. T. Wang. A. K. Monro & Y. G. Wei in Phytotaxa 147（1）： 7. 2013.
Achenes brownish， ellipsoid， 0.790-0.985 × 0.412-0.499 mm， length：width ratio 1.8-2.3：1， longitudinally 4ribbed， and between each pair of ribs sparsely tuberculatepuncticulate （Fig. 1： B； Fig. 2： B； Fig. 3： B）.
Voucher specimen：
Guangxi：Longzhou County， Banbi， April 2011， Y. G. Wei & F. Wen 1176 （IBK）.
Elatostema heterocladum is the most similar to E. androstachyum W. T. Wang， A. K. Monro & Y. G. Wei （Wei et al， 2013）. The differences of achene between two species are that the former one is brownish （vs. beige）， has bigger size （0.790-0.985 × 0.412-0.499 Fig. 1Illustration of achenes of seven Elatostema speciesA. E. angulaticaule W. T. Wang & Y. G. Wei； B. E. heterocladum
W. T. Wang. A. K. Monro & Y. G. Wei； C. E. obscurinerve W. T. Wang； D. E. planinerve W. T. Wang & Y. G. Wei；
E. E. pseudolongipes W. T. Wang & Y. G. Wei； F. E. longibracteatum W. T. Wang； G. E. subtrichotomum
W. T. Wang. The same below. （Illustrated by LIN WenHong）
Fig. 2LM photos of achenes of seven Elatostema species
Fig. 3SEM photos of achenes of seven Elatostema species
mm vs. ca. 0.65 × 0.3 mm） and surface with longitudinally 4ribbed， and between each pair of ribs sparsely tuberculatepuncticulate （vs. 5 longitudinal ribs）.
2.3 Elatostema obscurinerve W. T. Wang in Bull. Bot. Lab. N. E. Forest. Inst. 7： 63. 1980.
Achenes brownish， ellipsoid， 0.550-0.741 × 0.283-0.355 mm， length： width ratio 1.9-2.1：1， longitudinally 6ribbed （Fig. 1： C； Fig. 2： C； Fig. 3： C）.
Voucher specimen：
Guangxi： Fengshan County， Yunfeng Cave， 27 April 2011， Y. G. Wei & F. Wen C005E1 （IBK）.
Elatostema obscurinerve is the most similar to E. involucratum Franch. et Sav. （Wang， 1980）. The differences of achene between two species are that the former one has smaller size （0.550-0.741 mm vs. 0.7-0.8 mm） and surface with longitudinally 6ribbed （vs. longitudinally 6ribbed and tuberculate）. 2.4 Elatostema planinerve W. T. Wang & Y. G. Wei in Nordic J. Bot. 30： 1. 2012.
Achenes brownish，ellipsoid， 0.552-0.566 × 0.297-0.331 mm， length：width ratio 1.7-1.8：1， longitudinally 6ribbed （Fig. 1： D； Fig. 2： D； Fig. 3： D）.
Voucher specimen：
Guizhou： Xingyi City，31 March 2010， Y. G. Wei & F. Wen 1027 （IBK）.
Elatostema planinerve is the most similar to E. bracteosum （Wen et al， 2012）. The differences of achene between two species are that the former one has smaller size （0.552-0.566 mm vs. 0.7-1 mm） and surface with longitudinally 6ribbed （vs. longitudinally 6ribbed and tuberculate）.
2.5 Elatostema pseudolongipes W. T. Wang & Y. G. Wei in Elatostema （Urticaeae） in China 279. 2014.
Achenes brownish， ellipsoid， 0.618-0.682 × 0.366-0.398 mm， length：width ratio 1.6-1.8：1， tuberculate （Fig. 1： E； Fig. 2： E； Fig. 3： E）.
Voucher specimen：
Guangxi： Longzhou County， Banbi， 21 May 2010， Y. G. Wei & A. K. Monro AM6813 （IBK）.
Elatostema pseudolongipes is the most similar to E. longipes W. T. Wang （Wang， 2014）. The differences of achene between two species are that the former one has smaller size （0.618-0.682 mm vs. ca. 0.8 mm） and surface with tuberculate （vs. longitudinally 6ribbed）.
2.6 Elatostema longibracteatum W. T. Wang in Bull. Bot. Res. Harbin 2（1）： 6. 1982.
Achenes brownish， ellipsoid， 0.540-0.687 × 0.243-0.293 mm， length：width ratio 2.0-2.5：1， longitudinally 68ribbed （Fig. 1： F； Fig. 2： F； Fig. 3： F）.
Voucher specimen：
Yunnan： Malipo County， Niuchang Village， 2 May 2013，L. F. Fu & S. L. Huang FL0020 （IBK）.
Elatostema longibracteatum is the most similar to E. asterocephalum W. T. Wang （Wang， 1982）. The differences of achene between two species are that the former one has smaller size （0.540-0.687 mm vs. 0.8 mm） and surface with longitudinally 68ribbed （vs. longitudinally 68ribbed and tuberculate）.
2.7 Elatostema subtrichotomum W. T. Wang in Bull. Bot. Lab. N. E. Forest. Inst. 7： 25. 1980.
Achenes brownish， ovoidellipsoid， 0.600-0.664 × 0.277-0.336 mm， length：width ratio 1.8.0-2.3：1， longitudinally 45ridded， between each pair of ribs sparsely tuberculate and two opposite rids winged （Fig. 1：G； Fig. 2： G； Fig. 3： G）.
Voucher specimen：
Guizhou： Guiyang City， Zijiang Difeng， 16 May 2012， Y. H. Tseng & L. F. Fu Zn1267 （IBK）.
Elatostema subtrichotomum is the most similar to E. oblongifolium Fu ex W. T. Wang （Wang， 1980）. The differences of achene between two species are that the former one has smaller size （0.600-0.664 mm vs. 0.8-0.9 mm） and surface with longitudinally 45ridded， between each pair of ribs sparsely tuberculate and two opposite rids winged （vs. longitudinally 6ribbed）. AcknowledgementsWe would like to thank LIN WenHong for the illustration and Dr. DONG LiNa for her constructive suggestions on the manuscript. We also thank the herbarium of Guangxi Institute of Botany （IBK） for checking specimens.
References：
FU LF， DO VT， WEN F， et al， 2014. Elatostema arcuatobracteatum （Urticaceae）， a new species from Vietnam [J]. Phytotaxa， 174（2）： 111-115.
LIN Q， FRIIS I， WILMOTDEAR MC， 2003. Elatostema [M]//WU ZY， RAVEN PH. Flora of China. Beijing： Science Press； St. Louis， Missouri： Missouri Botanical Garden Press， 5： 76-189.
LIU CJ， LIN Q， HE JX， 2004. Methods and terminology of study on seed morphology from China [J]. Acta Bot BorealOccident Sin， 24（1）： 178-188. [刘长江， 林祁， 贺建秀， 2004. 中国植物种子形态学研究方法和術语 [J]. 西北植物学报， 24（1）： 178-188.]
WANG WT， 1980. Classificatio specierum sinicarum Elatostematis （Urticaceae） [J]. Bull Bot Lab NE For Inst， 7： 1-96. [王文采， 1980. 中国荨麻科楼梯草属分类 [J]. 东北林学院植物研究室汇刊， 7： 1-96.]
WANG WT， 1982. Taxa Nova Pellioniae Elatostematisque E Sina [J]. Bull Bot Res， 2（1）： 1-31. [王文采， 1982. 赤车属和楼梯草属新分类群 [J]. 植物研究， 2（1）： 1-31.]
WANG WT， 1995. Elatostema [M]//WANG WT， CHEN CJ. Flora Reipubicae Popularis Sinicae. Beijing： Science Press， 23（2）： 187-317. [王文采， 1995. 楼梯草属 [M]//王文采， 陈家瑞. 中国植物志， 23（2）： 187-317.]
WANG WT， 2014.Elatostema （Urticaceae） in China [M]. Qingdao： Qingdao Press. [王文采， 2014. 中国楼梯草属植物 [M]. 青岛： 青岛出版社.]
WEI YG， MONRO AK， WANG WT， 2013. Additions to the flora of China： three new species of Elatostema （Urticaceae） from Guangxi [J]. Phytotaxa， 147（1）： 1-12.
WEI YG， WANG WT， 2009. Notes on Elatostema J.R. et G. Forst. （Urticaceae） from Guangxi [J]. Guihaia， 29（6）： 711-718. [韦毅刚， 王文采， 2009. 广西楼梯草属研究随记 [J]. 广西植物， 29（6）： 711-718.]
WEN F， FU LF， WEI YG， et al， 2013. Elatostema planinerve and E. longicuspe spp. nov. （Urticaceae） from Guizhou Province， China [J]. Nord J Bot， 31： 312-315.
WU ZY， WANG H， LI DZ， 2012. Supplementary description of achenes of seven species in Elatostema （Urticaceae） [J]. Guihaia， 32（5）： 603-606. [吴增源， 王红， 李德铢， 2012. 荨麻科楼梯草属七种植物果实的补充描述 [J]. 广西植物， 32（5）： 603-606.]