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[APD] Re: Aquatic vs Aquarium Plants - and cuticles

Here is a little bit more about the habitat of Stephan's seasonally
flooded aquatic plants, Elatine gussonei & Crassula vaillantii!

From: <http://www.nature.coe.int/istanbul/Em(2001)7.doc>

Application and development of the Palaearctic habitat classification in
the course of the setting up of the Emerald Project - Malta - by Pierre
and Jean Devillers-Terschuren

"22.3418. Mediterranean amphibious small herb communities

Formations of Mediterranean temporarily inundated or wet terrain,
including karstic pools, often highly ephemeral, dominated by annual
small herbs, among which Elatine spp. (Elatine macropoda, Elatine
gussonei, Elatine pedunculata), Damasonium bourgaei, Nananthea
perpusilla, Morisia monanthos, Radiola linoides, Myosurus minimus,
Laurentia gasparrinii.
(Molinier and Martin, 1980: XLII; Pignatti, 1982: II 136-137; Lanfranco,
1989: 24, 36; Gamisans, 1991: 126-127, 219; Lanfranco, 1999a, 1999b). "

Ephemeral: short-lived or fleeting.

Karstic: characterized by eroded limestone cavities.

See: Bob Hurt's Central Florida Geology
<http://rainsoft.ws/bad_water.htm >

"What Karstic Means.  Karst is a region in the Balkans whose underlying
rock is limestone, slowly dissolving in the groundwater, giving it a
distinctive terrain and water cycle. "Karstic" lands comprise five to
ten percent of the Earth's land surface, where oceans have retreated as
they did in Florida. Million of years ago Florida was under water;
calcium crystals and seashells sank to this ocean floor and over
millions of years compacted into hard limestone. As the ocean dropped
Florida became covered by plants and soil, and subject to rainwater.

"Effects of Acid Rain.  As rain falls through the sky it absorbs carbon
dioxide, making it slightly acidic. All stone is subject to this acid,
but limestone dissolves especially rapidly, and its cracked, fractured
structure lets the water seep down through it. Over many years,
elaborate networks of tunnels and caves form underground, often with a
honeycomb of vertical "pipes" which drain the area underground, rather
than through ordinary streams and rivers draining laterally to the
ocean. Karstic areas have few streams. Other features of a karstic
landscape are artesian springs, "underground rivers", natural bridges,
caves, quicksand, and especially sinkholes.

"Sinkholes.  A sinkhole forms when the roof of an underground cave
collapses and the rock and soil above it drop down to fill the void. "

A karstic biotope would be alkaline possessing carbonates from the
limestone. These carbonates could provide a source of carbon necessary
to support photosynthesis of Elatine gussonei when submerged. The short
period of inundation & followed by rapid drying & desiccating conditions
would require the plant to retain its protective waxy cuticle on its
leaves. The period of inundation may be too brief to require the plant
to grow specialized submerse leaves.

In the words of Spock: Fascinating! ;-)

Steve P in Vancouver

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