Date: Mon, 19 Oct 1998 14:37:10 +1000 From: "Mark T. Bachelor" <bachelor@gateway.mggs.vic.edu.au> To: cp@opus.hpl.hp.com Message-Id: <aabcdefg3314$foo@default> Subject: Re: D. peltata/auriculata ID
>
>I have been growing 20 or so plants of D. peltata and D. auriculata in a 10"
>pot for the past year. They have been in a state of semi-continuous growth
>since November of 1997. When one dies back another invariably takes its
>place within a few weeks. From good advice supplied by growers on the
>listserve I have been keeping the pot in a moist state, letting the top get
>a tad dry before supplying more water.
You can also let them slowly dry out over summer and let them go dormant,
which is the normal growth habit of these plants. Easy to grow aren't
they? Watch out that they don't take over!
>
>Anyway, my question. Is there a way of telling these two closely related
>species apart? Are the floral parts the only way?
They are two sub-species of D. peltata (if you actually have two different
plants) and yes floral parts is the best way to tell the difference. The
other ways are seed shape and whether or not the flowers open in shade. D.
peltata peltata requires full sun to flower successfully.
When I planted them out
>last year the tubers pretty much looked the same- red and globose.
>From my experience D. peltata peltata has small white tubers and D. peltata
auriculata has larger pink tubers. However colour can vary depending on the
source of the plants. All of my plants are from around Melbourne.
I have a
>copy of Allen Lowrie's excellent book CP OF AUSTRALIA Vol. 1 but it only
>contains a description of the Western Australian D. peltata.
D. peltata peltata only seems to vary in colour, from the typical bright
green to a reddish pink like that of D. peltata auriculata (which can also
be green in shade). The most common form D. peltata ssp.peltata typica
(excuse my incorrect naming Jan, I can't remember if it is a form or a
variety) is bright green with white flowers and is found both in Australia
and overseas. Red plants can come up amongst a population of what was all
green plants.
I had more details to hand earlier in the year so check the back issues of
the digest. I put on a copy of the complete listing of the known D. peltata
subspecies and varieties.
>
>Some of the plants I have growing contain a small basal rosette and aerial
>parts
Juvinile plants growing to about 15 cm high, few flowers.
>while others lack this ground portion and have a pronounced reddish
>aerial stem.
Mature plants often exceeding 20 cm high. My auriculatas are over 50 cm
high and have multiple flower heads due to a number of side branches. Watch
as particular plants age. As the tuber becomes larger, the basal rosette is
lost. However it does appear that it may be possible to reverse this if the
tuber does not get enough food reserves to cope with putting up a stem
before producing leaves.
>The lamina on all plants (the aerial portions) are green with a
>hint of yellowish gold.
Regards
Mark T Bachelor
Biology Technican
Melbourne Girls Grammar School Voice: +61 (03) 9866 1676
South Yarra, Victoria, Fax: +61 (O3) 9866 5768
Australia 3141
National Science Week, STAV Family Day Co-ordinator
Lab Techs' Branch of STAV, South Yarra & Moorabbin Regional Rep.
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