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The Restoration of the Genus Cyclocodon ( Campanulaceae) and Its Evidence from Pollen and Seed-coat

HONG De-Yuan, PAN Kai-Yu   

  • Received:1900-01-01 Revised:1900-01-01 Online:1998-03-10 Published:1998-03-10
  • Contact: HONG De-Yuan

Abstract:

 The genus Cyclocodon Griff. was reduced by C. B. Clarke in 1881 into a section
of the genus Campanumoea. Our LM and SEM observations on pollen morphology show
that the pollen of all the three species in the former is 3-colporate with the exine sparsely
high-spinulose, whereas that of the two species in the latter is 5~8-colpate with the exine
relatively densely short-spinulose. SEM observations on seed-coat indicate that the primary
ornamentation of the seed-coat of the two species in Campanumoea (s. str. ) is characterized
by regular and polygonal areoles which are much larger than the radial walls in diameter and
by the bead-like secondary ornamentation on the radial walls, while that of the three species
in Cyclocodon is characterized by irregular-shaped areoles which are nearly equal to the radial
walls in diameter and by the rope-like secondary ornamentation on the radial walls. Thus,
the pollen morphology is closely correlated with the seed-coat morphology. Taking the char-
acteristics of pollen, seed-coat and gross morphology into consideration,  the genus Cy-
clocodon is restored, separate from Campanumoea (s. str. ). One new combination, Cy-
clocodon celebicus (B1.)Hong, is made in the present paper. The genus Cyclocodon is con-
sidered closely related to Platycodon rather than to Campanumoa.

Key words: Campanulaceae, Campanumoea, Cyclocoden, Pollen, Seed-coat, Taxonomicalrevision