Abstract
The difficulties involved in the taxonomy of the genus
Crassula, such as the extensive variation and often difficult
species complexes, vicariousness and hybridization, are sketched
against a historical background. These difficulties have prompted
the author to review concepts of taxa from subspecific to generic
level and have also le~ to the approach adopted in this work.
It is argued that in several genera and sections, as
previously recognized, too much stress was placed on the several
floral characters which form part of a pollination syndrome which
is shown up by convergent developments of these flower typeso
The diff~rent types of seedling mprphology recognized
are considered in relation to the morphology of adult plants and
their affinities at specific and sectional level.
The distribution of the hydathodes has proved useful in
the delimitation of supraspecific taxau ThB morphology of the
developing seedlings and the distribution of the hydathodes on ,
the leaves become the main arguments for a new classification in
the genus Crassula.
A cytological review stresses the different basic chromosome
numbers (8,7) and their structural differences for the de~
limitation of the subgenerao Problems in determining the original
basic number and the high percent~ge of polyploidy with various
rainfall conditions are evaluated.
Subsequently the characteristics and affinities of
Crassula and its subgeneric taxa are briefly discussed.
The key to the species, subspecies and varieties is
divided into twelve groups which are similar to sections or groups
of sections recognized.
TOLKEN, H (2021). Taxonomic Studies On The Genus Crassula L.. Afribary. Retrieved from https://tracking.afribary.com/works/taxonomic-studies-on-the-genus-crassula-l
TOLKEN, HELLMUT "Taxonomic Studies On The Genus Crassula L." Afribary. Afribary, 15 May. 2021, https://tracking.afribary.com/works/taxonomic-studies-on-the-genus-crassula-l. Accessed 18 Dec. 2024.
TOLKEN, HELLMUT . "Taxonomic Studies On The Genus Crassula L.". Afribary, Afribary, 15 May. 2021. Web. 18 Dec. 2024. < https://tracking.afribary.com/works/taxonomic-studies-on-the-genus-crassula-l >.
TOLKEN, HELLMUT . "Taxonomic Studies On The Genus Crassula L." Afribary (2021). Accessed December 18, 2024. https://tracking.afribary.com/works/taxonomic-studies-on-the-genus-crassula-l