Plantlets on kalanchoe leaves

David Hershey dh321z at yahoo.com
Thu Oct 31 21:34:58 EST 2002


Kalanchoe daigremontiana versus Bryophyllum
daigremontianum is a classic "lumper" versus
"splitter" debate. The lumpers have considered the
flower structure differences as too minor to justify a
separate genus for Bryophyllum. This goes back to at
least 1930 when Berger keyed Bryophyllum from
Kalanchoe mainly on the insertion of the filaments in
the corolla tube. They are supposedly inserted at the
base in Bryophyllum and in the middle, or above, in
Kalanchoe. However, Turrill in the 1951 Curtis's
Botanical Magazine reported that for Bryophyllum
daigremontianum, the filaments were actually inserted
"somewhere near the middle." Thus, there is
inconsistency even in the flower structure differences
on which Bryophyllum was originally based. In 1938,
Baldwin (Amer. J. Botany 25:572-579) used "evidence
from taxonomy, embryology and cytology" to conclude
that there should be no separate genus Bryophyllum.
The following webpage noted the recent proposed change
from Kalanchoe to Bryophyllum and astutely asked "how
much actual, not bibliographic research is the base
for this?" That is a very legitimate question.

http://nhncml.leidenuniv.nl/fmbull/fmb54_s.htm

The recent justification for Bryophyllum is supposedly
based on their pendulous flowers and epiphyllous
plantlets but still apparently uses the unreliable
filament insertion too. None of that is new. Also, you
note that not all proposed Bryophyllum species have
epiphyllous plantlets so that is not a reliable
differentiating characteristic either. It even
contradicts the genus name, which means "sprouting
leaf." The following website talks about a "consensus"
for Bryophyllum but notes that the situation is far
from clear because removing Bryophyllum from Kalanchoe
may make it paraphyletic, which is bad thing in
taxonomy. 

http://hbs.bishopmuseum.org/pdf/op68-03.pdf

Another complicating factor is that Bryophyllum is
also a genus in the Kingdom Protista according to the
several websites, including the following one: Isn't
that a violation of the rules of nomenclature?  

http://protist.i.hosei.ac.jp/PDB/Images/Ciliophora/Bryophyllum/index.html
  
I gave both scientific names because it is often
listed both ways. The original publication in 1914 by
Hamet and Perrier used Kalanchoe daigremontiana Then
in 1930, Bryophyllum daigremontianum was proposed by
Berger which was accepted by a few. In a 1934 article,
Charles Swingle, who introduced the plant into the
USA, was still calling it Kalanchoe daigremontiana. 

In the scientific research literature, Kalanchoe
daigremontiana predominates by about a 3:1 ratio over
Bryophyllum daigremontianum, particularly in the last
twenty years. The Science Citation Index lists 209
references for Kalanchoe daigremontiana but just 68
for Bryophyllum daigremontianum and just 10 of the 68
are newer than 1980. BIOSIS lists 342 for Kalanchoe
daigremontiana and 111 for Bryophyllum
daigremontianum. A search on google.com gives 510
sites for Kalanchoe daigremontiana and 160 for
Bryophyllum daigremontianum.

The vast majority of plant reference books list
Kalanchoe daigremontiana including: 
Hortus Second 
Hortus Third 
Hortica 
New Royal Horticultural Society Dictionary of
Gardening 
New York Botanical Garden Illustrated Encyclopedia of
Horticulture 
American Horticultural Society Encyclopedia of Garden
Plants 
Manual of Cultivated Plants by Bailey
Wyman's Gardening Encyclopedia 
Handbook of Succulent Plants by Jacobsen
Illustrated Encyclopedia of Succulents by Rowley

The online USDA Plants Database also uses Kalanchoe
daigremontiana. The only major plant reference in a
university library reference section that listed
Bryophyllum daigremontianum was the 1956 Royal
Horticultural Society Dictionary of Gardening which is
superceded by the 1992 New Royal Horticultural Society
Dictionary of Gardening.

The current "correct" plant scientific name for a
particular species is going to remain an uncertain
area for plant scientists who are not taxonomists but
need to use scientific names in their publications. To
eliminate the uncertainty, it would be extremely
useful if professional plant taxonomists would put
together a website that gives the current "consensus"
scientific names for every plant species.  

David R. Hershey


----- Original Message ----- 
From: Cereoid+10 <cereoid at prodigy.net> 
Newsgroups: bionet.plants.education 
Sent: Wednesday, October 30, 2002 8:10 PM 
Subject: Re: Plantlets on kalanchoe leaves 

> Sorry dude, the name Bryophyllum daigremontianum is
the correct one for the
> plant. The genus Bryophyllum has recently been
reinstated because the flower
> structure differs considerably from Kalanchoe.
Several species and hybrids
> of Bryophyllum are viviparous but not all.
> 
> Different degrees of vivipary are found throughout
the Crassulaceae but
> there are a select few that produce adventitious
plantlets.
> 
> 
> David Hershey <dh321z at yahoo.com> wrote in message
> news:ap52uo$cub$1 at mercury.hgmp.mrc.ac.uk...
> > They are variously termed adventitious plantlets,
> > viviparous plantlets, epiphyllous buds, epiphytic
> > buds, and pseudobulbils. The most studied species
is
> > probably Kalanchoe daigremontiana, formerly
> > Bryophyllum daigremontianum. I recently wrote a
> > teaching article on using plantlet formation to
study
> > photoperiodism:
> >
> > Hershey, D.R. 2002. Using the Kalanchoe
daigremontiana
> > plant to show the effects of photoperiodism on
> > plantlet formation. Science Activities 39(2): 30-34.

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