Thai wat architecture: dok so fa

Thai wat architecture: dok so fa

(there will be no new posts until Thursday)

Thai wats have chofah (ช่อฟ้า; lit. sky tassel) at the top of the end of the roof and hang hong (หางหงส์) at the gable.

http://en.wikipedia.org/wiki/Chofah or for a wordier version: http://bangkokbois-gay-thailand-blog.com/2013/06/21/buddhism-101-cho-fa-cho-fah-chofah-gesundheit/

But in Lao and northern Thailand, I noticed structures in the middle of the roof ridge of wats, that are absent in central Thailand.

A book I was browsing in a bookshop said these are "dok so faa", but this gave no hits on google, however "dok so fa" does (google images, the quickest way to confirm if a name in Thai or in English is what I think it is).

But what is the Thai spelling of "dok so fa"? ดอกช่อฟ้า doesn't give hits on google, and ใบระกา and หางหงส์ have been suggested by friends, but are different structural elements (and are pronounced completely different anyway: "bai ra ga" and "hang hong").

Pictures of Wats with "dok so fa" I took in Vientiane, Luang Prabang and Chiang Rai:

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