What is interesting is the red hairs on the leaf sheath is mentioned as being present in very few species, the other species do not have the broad leaves. I have seen this mentioned in several places, but in none have I seen the hairiness or not of the flower spathes being mentioned as an identifying factor.
There's a lot of info on this pdf:
http://herman.marc.usda.gov/sp...
The argument as to whether a plant can be defined as annual or perennial I think does depend on how anyone views the meaning of each. Even if something acts as an annual in one location, but is perennial in another, should in my view be called whatever the behaviour exhibits for that location. e.g. species X is annual in one location, but is perennial in another location, then they must surely be defined as to how they act for each location? How could a plant be called a perennial if it doesn't behave like a perennial for a certain location? If it grows from seed and dies in one year, then it is 'annual', but if it remains dormant due to dryness but the roots regrow when rain allows it to, then it should be called perennial due to the fact the plant has survived even if not in growth.
I think labelling plants as a definite type of plant, i.e. annual, perennial or biennial is more a means of describing how a plant will behave than being attached to the actual description of the plant. True, some plants can be definitely annual, and some will be permanently perennial with many dying back in a season (not always in winter!) and retaining the roots with growth eyes waiting to spring into life again when conditions allow. Where plants are able to behave in different ways to what people consider to be 'normal' for a certain location should not define, in my opinion, the exact annual/biennial/perennial nature of plants. Perhaps people have tagged plants with these descriptions as a matter of conforming to make information available to the people who want to grow them. Plants don't know about that part of human nature.
Then we get into whether a plant is deciduous, evergreen, or semi-evergreen!
