Hymenocallis, Dunes. and STOLONS

ConroeJoe@aol.com ConroeJoe@aol.com
Tue, 26 Oct 2004 15:45:59 PDT
Hi,

I have not seen 1-foot-long extensions from Hymenocallis liriosme, the local 
species.  However, I have seen downward extensions from the bulbs sometimes, 
and such tissues can be up to 5-6 inches long.  I have not examined them 
closely and could not say for sure  if they are modified stems or modified roots, 
but they sure don't seem to be modified leaves.  

Nonetheless, sometimes the downward extensions (of H. liriosme) have linked 
one bulb to another.  So, you can do a thought experiment to create a 
hypothesis if you lay out certain starting points.
1.  Roots don't give rise to shoots (generally), only stems give rise to 
shoots.  
2.  By linking 2 bulbs, you can suppose that the underground extension grew 
out of one bulb and gave rise to the second bulb (hence, not a root but a 
stem).  
3.  By similar logic, an underground leave is eliminated.
4.  Underground stems that give rise to shoots are stolons because rhizomes 
are "the main underground stem."  (This assumes that the bulb part is the "main 
stem")

With this type of fly-by-the-seat-of-my-pants thinking, as well as the 
knowledge that stolons do occur in closely related species, I've been supposing the 
downward extending parts are stolons.  It is true though that they sometimes 
grow right out of the bottom of a bulb and grow downwards.  

It is interesting that you surmise the plants in your area use the extensions 
to keep near the surface instead of being deeply buried.  Here in Texas, with 
H. liriosme, I've supposed that they use the extensions (and roots too) to 
pull the bulbs deeply into the soil.  The bottom of bulbs can be 12 inches or 15 
inches below the soil line--if you plant them in gardens they eventually make 
deeply buried clumps.  


Cordially,

Conroe Joe



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