No Phragmites
As you may know, the Yin Chiao formula contains herbs for both Wind-Heat and Wind-Cold conditions, and generally works well for both types of illness.
But the fact is that people mainly use Yin Chiao for Wind-Cold conditions like the common cold, and hardly ever use it for Wind-Heat conditions like the flu or measles.
Though Phragmites (Lu Gen) reduces the high fever and thirst of caused by Wind-Heat, you wouldn’t use this extremely cold herb in a formula that you knew was going to be used strictly for Wind-Cold caused illness .  At best, the herb would just be taking up space, and at worse might hinder the action of the formula. 
We’ve found that when you use Yin Chiao for the common cold, it works better without the Lu Gen.