Mysterious nameless blocks appear in statistics menu

What are those two grayish bar things? What is that snowy powder stuff?

On the first picture, those are melon and pumpkin stems.
On the second picture, it's the end portal

On the second picture, the end portal has it's own block code? (like the nether portal?) Is the end portal a separate block from the end portal frame?

And I don't even understand why these would even be showing up in this menu!

Yes, the End Portal has its own ID (119, if I recall correctly), and can be obtained through /give. Though, the 'powder stuff' may also refer to block 39❓ which is the Block Moved by Piston, also obtainable through /give. You might have used them in an earlier stage before 1.4, as the Statistics don't change when the version does.

I think the snowy texture is the End Portal itself, not the frame surrounding it.

Blocks you cannot normally attain but you can /give to yourself simply has no tooltip as... they cannot be normally attained.

But the thing is I have never done this before! I have not used the /give command to give myself these blocks, so they should not be appearing there!

And they should at least have their label so you know what they are.