Abstract: The floral numerical variation and seed setting of an endemic plant of China Liriodendron chinense (Hemsl.) Sarg. were observed during 1994 to 1996 in three natural populations, located respectively in Songtao County, Guizhou Province (briefly G), Kelipo, Longshan County, Hunan Province (H) and Longwangshan Nature Reserv., Anji County, Zhejiang Province (Z). In general, the number of perianth segments is nine. The variation including ten, eleven, and twelve was reported. Pollen quantity of a single flower, pollen size and the number of pistils were found less variated in Population Z than that in Population G and H, the two populations having numerical perianth variation. Furthermore, the seed production of the two populations was higher than population Z. There was a significant positive correlation ( r = 0.76) between the mean pollen size and seed set in populations. Comparing the seed set with the pollen ovule ratios (P/O) in the three populations, based on three years data,it was found that a population with lower P/O rate usually tended to produce higher seed set. This suggested that resource allocation limited the seed set of this endangered plant, and the relationship between the floral numerical variation and seed set in populations indicated that the potential genetic diversity had significant influence on seed production.

Key words: Liriodron chinense, Floral numerical variation, Pollen ovule ratios, Seed set