Home arrow Cycas Taxonomy arrow The subgenera, sections, and species of Cycas
The subgenera, sections, and species of Cycas PDF Print E-mail
Written by David J. de Laubenfels   
Wednesday, 10 October 2007
Article Index
The subgenera, sections, and species of Cycas
First Section of Cycas
Second Section of Cycas
Third Section of Cycas
Fourth Section of Cycas
Fifth Section of Cycas
Sixth Section of Cycas
Page 1 of 7

Cycas Media
Cycas Media
Virtually all treatments of the genus Cycas, at some level, divide the species into those with serrulate margins of the megasporophyll apex and those with pectinate margins.  Thus, Wang (1996 in Wang & Liang, Cycads in China: 26 & 28) used two subgenera, Cycas (serrulate) and Panzhihuaensis Wang (pectinate; Revoluta de Laub., 1998, Blumea 43: 382).  The teeth on serrulate examples can reach 12 or rarely even 15 mm and the longest such teeth (except on four Australian species with peg-like teeth) increase apically.

Where shorter segments on pectinate examples occur these are always found towards the apex as a result of apical decrease and generally the longest segments are at least 18 mm long.  Not only are the two subgenera thus morphologically sharply differentiated, but geographically they are also segregated.  The two subgenera overlap minimally along the southern fringes of southeastern Asia and in the Philippines.

Related Cycas Information from the Royal Botanic Gardens


Prev - Next >>
Last Updated ( Sunday, 09 March 2008 )
 
Next >
[ Back ]