Abstract:

Transmission electron microscopy (TEM) observation of pollen grains of 18 species belonging to 18 respective genera of the tribe Peucedaneae Drude revealed distinct ultrastructural difference in the pollen exine, including the thickness and features of tectum, columnar layer, foot layer and endexine. The systematic position of those 18 species are re-evaluated based on their ultrastructural characteristics of pollen exine observed in this study. Seven genera related to Angelica L. in Angelicinae Drude have been deduced to genus Angelica L. For example, Ostericum grosseserratum (Maxim.) Kitagawa was changed to Angelica L. by some authors, but it differs from Angelica sinensis (Oliv.) Diels in having well developed tectum which is thicker than the columnar layer and foot layer. Its columnar layer is quite well-developed with long and branched columellae. Besides its surface is tuberculated. Evidently, its development exceeds that of Angelica sinensis. However, it is only a moderate evolutional species in its genus, and the Angelica sinensis accounts as the most advanced species in Angelica Diels, thus, placing genus Ostericum Hoffm. in Angelica L. is not suitable, it may be more appropriate to keep its original position. In addition, Ferula akitschkensis B. Fedtsch. ex K.-Pol. differs greatly from those of Talassia transiliensis (Herd.) Korov. and Schumannia turcomnnia Kuntze, because of its very well-developed columnar layer, being about four to five times thicker than the total of tectum and foot layer, tuberculated tectum surface and complicated structure of columnellae. As another species Heracleum forrestii Wolff also differs from Semenovia rubtzovii (Schischk.) Monden. in having an even thickness of exine and well-developed columnar layer, it seems suitable that they should also be treated as two independent genera.

Key words: Peucedaneae Drude, pollen exine, ultrastructure, systematic position