Roots

I feel I covered a lot of root describing in the last post. I shall sum it up. 

The plant is a prairie plant. Prairies are low in water. The plants must have long roots to access the deep water tables. V. Thapsus is one of those plants with long, deep roots. No body has been able to measure the length of the tap root. The most people usually get is a couple feet down before they get impatient and snap it off. Here is a picture of V. Thapsus' tap root. As seen it is thick. 

On a side note you can see that the plant has it's growth center not above ground, but under/at ground level.  (Like the quiescent center but for the upward growth)This helps when a forest fire of herbivores eat/destroy the top of the plant. The V. Thapsus is able to regenerate new leaves quickly and is able to continue photosynthesizing. The stem on the plant is very small and the leaves are the main mass of the plant. 

This plant does have lateral roots, although they are not as main as the tap root. There are significantly less lateral roots.  

As for mycorrhize, I have not found any information. I looked at several different web sites which all talk about germinating and planing this plant, and they don't say anything about making sure there is the right species of mycorrhize. Their plants do well. I would assume that this means the plant uses a generic species of mycorrhize that can be found in the prairies. Most likely an arbuscular mycorrhize The mycorrhize would help with lack of lateral roots. The fungi would help the plants have enough nutrients, and in turn the plants would give the mycorrhize carbon or sugars or what ever it would need. The fungi would also help in collecting rain water and delivering it to the plant.