Physical Description

Cryptodendrum adhaesivum can grow up to a diameter of 75cm¹ with a 30cm diameter oral disc when expanded². The unlobed oral disc³ is flat to wavy when expanded, but can be undulating⁴, particularly so in strongly contracted individuals³. It is entirely covered in extremely short (to 5mm in length) and sticky tentacles that are densely packed together, except around its mouth, which gives it a furry-looking appearance^1,2. Although the tentacles are extremely sticky, they do not detach with contact, unlike some other anemones such as Stichodactyla haddoni¹.

There are three differently shaped tentacles:

1) short with a narrow stalk and branched into five or more short finger-like projections at the tip in the center of the oral disc^1,2

Tentacles are narrow and branched at the tip into short finger-like projections (left); close-up of a few tentacles under a dissecting microscope (right)
 
2) simple elongate stalks that end in a bulb about 0.1cm in diameter near the edge on the outer rim of the disc^1,2

Tentacles have tips that end in bulbs (left); close-up of bulb-shaped tips under a dissecting microscope (right)

3) in addition, bordering the extreme margin of the oral disc is another type of tentacle that looks similar to those in the center but with fewer branches^1,2. They are sometimes referred to as 'verrucae'^2,3.

Tentacle is branched like those in the oral disc, but with less branches 

C. adhaesivum occurs in a wide variety of colors¹. The elongate bulbs are always differently colored to the tentacles in the center, and the tentacle stalks and tips may also be of different colors. Some of the color combinations include yellow and pink, blue and grey, and green and brown, and there may be differently colored tentacles occurring in patches amongst the predominant color. The mouth area may take on a bright color, for instance fuchsia, yellow, green or white².

The column of C. adhaesivum is contractile but it has been noted to be as long as or longer than the oral disc width. It is also firm but will become wrinkled when contracted. The mouth is central and small, and is usually accompanied by two symmetrical siphonoglyphs³ (see Anatomy & Physiology).

Interestingly, many copepods were found living on this C. adhaevisum individual. Given they were unharmed by the nematocysts (see Defense Mechanisms), they could possibly have been ectoparasites. 
Various copepods observed darting about on the oral disc and tentacles of C. adhaesivum