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Re: Aquatic Plants Digest V1 #296


Subject: Re: Giant C wendtii & straw

Steve,
 
> > Not all Wendtii is so restrained.  In my tanks I have both red and green
> > varieties, and they are 16-18" tall ;-)
> 
> Wish that I had your problem! My two year old wendtii has leaves and
> stems around 6" but they grow kinda sideways so don't attain a large
> height. I've heard there are many varieties of this plant. What makes
> the difference between a variety and a species? Would mine attain these
> proportions given a different environment? How large can I hope to
> grow them? These leaves are much larger than the ones it had when I
> first got the plants. Mine have not produced any runners. Is there
> a way to propagate them for instance by root cuttings?

There _are_ different varieties of wendtii, and some are larger than others. 
 But if yours is not reproducing, it would lead me to believe that 
conditions aren't completely to it's liking.  It is one of the easiest 
Crypts, and tends to be _very_ prolific.  Unlike some Crypts, it does not 
send long runners out with plants popping up at great distances from the 
parent.  Instead, the runners are short, and the stand tends to get bigger 
and bigger, so it looks more like one large plant until you try to take it 
apart.  Then you will find that there are masses of individual plants, each 
with only about 5 leaves.  Is it possible that you are confusing this growth 
pattern with lack of reproduction?

As to what makes a species a species, the experts aren't sure, so I'm not 
gonna get in the middle of it!  That's why scientific names change all the 
time... New people come along with new ideas, and new information, and lines 
between species, subspecies and varieties shift.

There are a few things that make Crypts harder than other genera to 
classify.  They can look _very_ different depending on the conditions they 
are growing under.  I have photos of one stand of Crypts at various times 
over a 4 year period, as conditions changed in my tank.  If I didn't _know_ 
that it was the same plant, I don't think I'd believe it.

Second, like Day Lilies, some species of Crypts (even in the wild) come in 
diploid, (and I think triploid and tetraploid) varieties.  This can make 
them look very different, even if they are very closely related genetically.

Third, it is sometimes (fairly often) impossible to ascertain the species of 
a Crypt without examining the flower.  Since the plants do not flower 
readily in captivity, it has not been an uncommon for a plant to be in 
someone's greenhouse for years before it finally flowers and is discovered 
to be a new species.  Conversely, one that is _thought_ to be something new, 
can turn out to be a well known species once it flowers.  Neils Jacobsen has 
gone one step further and done genetic studies on many of these plants in an 
effort to classify them more accurately.

(more than you ever wanted to know about Crypts, eh?<g>)

> Subject: Straw for algae control?
> 
> I suspect the straw contains allelopathic chemicals which suppress
> algae growth. Straw comes from wheat, barley or oats which are just
> big domestic grasses; dead grass probably works too. Ever notice how
> nothing much else grows in a healthy lawn but grass? Same principle.

I don't know.  I have my doubts about this one.  One of the well known ways 
of getting a green water culture growing is with a handfull of crushed 
grass.


Subject: Green water

Neil,

> >Now my water is crystal clear (finally).  It cleared by itself (using a s
> >hang-on-tank filter with polyester batting in it) over a period of severa
> >weeks.  But now the water has a residual green tint to it (sort of like t
> >was some food coloring in it).  I am running the same filter with carbon 
> >but the green doesn't seem to be disappearing fast.   Any ideas?

> In both cases, fast growing plants are needed.  I have not found that > 
temporarily reducing the light is a good solution, but it can't hurt. 

I've actually had very good luck clearing up green water blooms by dpriving 
it of light.  But it hasn't been by cutting back the light just a little.  I 
have removed as much as possible from the water with either a diatom filter 
or by water changes, (to keep it from dying off in quantity and fouling the 
water) and cut the light _drastically_.  I turn the tank lights out, and 
cover all sides of the tank but one to cut down on ambient light as well.  I 
leave one end open just so the fish can see to eat, although I feed very 
lightly during this period.  I leave the tank in darkness for 5-7 days.  At 
the end of this time, the water has always been crystal clear, with no 
return of the algae.  The plants seem to tolerate this treatment without 
problem as well.

Karen

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