Hammer Differences...

[Z06-Hec]

If their are 2 types of Hammer coral, why the differences in them?

So for the Branching Hammer type...
Why are some long arms and smaller hammers and some much more thick stemmed with much larger hammers?
I have 2 different types of Aussie Hammers in my tank. Both Branching, both described as Bi Color Hammers.
1 is short with really fat stems and fat hammers
while my other set are skinnier long stemmed with smaller hammers in respect to other kind...

Again both are Aussie, Bi Color Branching hammers...

 

[Z06-Hec]

Also the 2nd picture, has grown from 2 heads to 6 in about 4-5 months time. The first picture has gotten puffier.. but i haven't noticed any splitting...

 

[Tab28]

There are two common varieties wall and branching. You have branching as you mentioned. Within the branching i have seen the tentacle tips in several shapes. Just like frogspawn the tentacle shapes vary. I think this may be just from where they are collected. My personal preference in the branching are the ones with the tips more hammer shaped than the rounded more blunt form. I would not classify the top purple tipped as a bi-color. The bottom pic is a bi-color. Two distinctly different tentacle tips. The tips are almost always a different color than tentacle.

Wall hammers are more similar shape tentacles basically anchor shaped.