Cephalocereus senilis blossom?

[shoshana5000]

I've had this cactus for a little less than two years, and I've assumed it to be a C. senilis. I've gotten a little confused lately by photos of similar cacti (Espostoa nana, for example), so maybe it's something else. It was about two and a half inches tall, maybe three, and among a very large assortment of young succulents in two inch plastic containers. So, now it is about five and a half inches tall, and just yesterday I noticed this little tuft on it. Is it actually an inflorescence? I thought C. senilis wouldn't bloom indoors--and not until it was very old. Or is this just a wad of lint? (Just kidding.) But I'm getting all excited about it, and just wondered if anyone can confirm the identification. Thanks for reading.

[Gerd Hayenga]

Hello,

your inflorescence looks a bit papery. Maybe it's just because of the picture(?) but it reminds me of similar objects I find on my cacti in these days. In my case there are spiders (Argiope bruennichi) responsible that build there egg sac on my plants.

[vtoman]

This looks more like an Espostoa (lanata?) to me.

[shoshana5000]

Thank you, Gerd Hayenga and vtoman for your responses. I'm afraid you may be right, Gerd, as we do (unfortunately) have a lot of spiders, and it doesn't look substantial enough to have a flower inside of it. Oh, well!

I appreciate the input from you both.

[greenknight]

Whether Cephalocereus or Espostoa it would first grow a cephaiium, from which the flowers would emerge. Spiders do like to lay eggs in the shelter of cactus spines, I think that's a good guess.

Looks like an Espostoa to me, too.

[DaveW]

It would also be quite an event if it flowered that small.

It was said by some in the past that the peudocephalia all face in the same compass direction, but this is not true. Graham Charles was showing us some habitat slides at the Cactus Explorers Weekend and showed that the pseudocephalia usually pointed outwards from the centre of the plant, presumably as the flowers are bat pollinated, outwards facing pseudocephalia are easier for bats to reach than having to fly in among the stems.

The pictures in the link enlarge if you click on them.

http://www.cactiguide.com/cactus/?uname ... toa%20nana

[shoshana5000]

Thanks for the different thoughts. Much appreciated. I am realizing I have even more to learn/understand about cacti than I realized! However, looking at the plant today, even though the change has been minor, I can tell it isn't a spider's egg sac. It is definitely plant growth, so I'm excited! I'll post another pic in a week or so, or whenever the change is more obvious in a photograph.