I think I sorted this out and it is something interesting, Desert Broomrape (Orobanche cooperi). Now the question is, do I try to destroy it, or let it play out?

Yes, it appears to be parasitizing two of my Agaves, and since I fancy myself an Agave collector, that is a problem. I've destroyed the flowers to stem the tide of seed production, and am considering pulling up and destroying the two host Agaves, in the hope that depriving the parasite of its hosts will lead to its demise. I am afraid it might sweep across the whole of my irrigated property and wipe out my entire collection.

Very interesting and quite pretty. I would have a hard time pulling it out. Does it weaken the host with its parasitic appetites or is it mannerly like the Indian paint brush . Some plants take but don't take too much. Maybe one can dig the agave out and clip back the roots that it is attached to and save the two agaves. I see that it is considered a "invasive" in California. A native invader. HMMMM, Or a Native fighting back against the invader alien tomato crop. Those pesky restless natives.

The Agave that serves as parasitic host #1 is not healthy. I've known for some time that it was afflicted by some mysterious malady, but never understood until now. It is probably safe to assume that anything called "broomrape" is not very mannerly.

Well that answers that question. There are parasites and then there are parasites. My mom was a host to a tapeworm for 8 months while she was pregnant with me. She did not look to good either.

Dig that bugger out. It would be interesting to see how it invades . What area of the plant/ Good luck on the rocky soil you have.

OK I pulled the A. vilmoriniana variegate up, and found nothing unusual, though I had removed a massive amount of broomrape plant/root several days ago with the flower stalks. I'll leave the plant outside for a week or so, then pot it up to see if that was enough to free it of the parasite. I still have a large A. guadalajarana to dig up, though it is not nearly as infested as the other.

BTW, now that we know what to look for, we're seeing plenty of broomrape blooms out in the desert on our habitat excursions.

curiouser and curiouser.

Most likely, the broomerape is parasitizing fresh supple root material, which is still in the ground, as opposed to the dried out stuff that came up with the plant.

SO interesting! Keep the updates and comments coming!

We found a different kind of broomrape out in habitat today. Meet Orobanche fasiculatus (Clustered Broomrape).

According to Wikipedia they are fairly host=specific and this one prefers Asteraceae ... You have any brittlebrush nearby? Desert Broom?

The clustered broomrape was found out in habitat near Cave Creek, the desert broomrape is on my property presumably parasitizing my Agaves. The only other plant in the vicinity is a Palo Verde tree. I understand many/most broomrapes are rather host-specific, but cultivation presents a whole new paradigm, and parasites might find suitable hosts they would never encounter in habitat.