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Transmission electron microscopy (TEM) observation of pollen grains of 18 species belongingto 18 respective genera of the tribe Peucedaneae Drude revealed distinct ultrastructural difference in thepollen exine, including the thickness and features of rectum, columnar layer, foot layer and endexine. Thesystematic position of those 18 species are re-evaluated based on their ultrastructural characteristics ofpollen exine observed in this study. Seven genera related to Angelica L. in Angelicinae Drude have beendeduced to genus Angelica L. For example, Osterfcum grosseserratum (Maxim.) Kitagawa was changed toAngelica L. by some authors, but it differs from Angelica sinensis (Oliv.) Diels in having well developedtectum which is thicker than the columnar layer and foot layer. Its columnar layer is quite well-developedwith long and branched columellae. Besides its surface is tuberculated. Evidently, its development exceedsthat of Angelica sinensis. However, it is only a moderate evolutional species in its genus, and the Angelicasinensis accounts as the most advanced species in Angelica Diels, thus, placing genus Ostencum Hoffm.in Angelica L is not suitable, it may be more appropriate to keep its original position. In addition, Ferulaakitschkensis B. Fedtsch. ex K.-Pol. differs greatly from those of Talassia transiliensis (Herd.) Korov. andSchumannia turcomnnia Kuntze, because of its very well-developed columnar layer, being about four tofive times thicker than the total of tectum and foot layer, tuberculated tectum surface and complicatedstructure of columnellae. As another species Heracleum forrestJ‘iWolff also differs from Semenovia rubtzovii(Schischk.) Monden. in having an even thickness of exine and well-developed columnar layer, it seemssuitable that they should also be treated as two independent genera. 相似文献
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弓翅芹属——伞形一科新属 总被引:1,自引:0,他引:1
复伞形花序分枝极多,侧伞形花序长度往往超过中央主伞形花序,组成为许多总状花丛,无总苞片和小总苞片,有时偶有1总苞片,但为膜质,脱落性;伞辐少数,纤细,极不等长,十分开展;每小伞形花序具少数花,花柄不等长,丝线形;花细小,花瓣白色,长卵形,基部具爪;花柱短粗,花柱基圆锥形,细小;萼齿显著,花粉粒为长球形。 相似文献
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