Is honey found in Arka trees?

[H. Isaacson]

The following subhaa.sita is often quoted (eg. "Sabara's Bhaa.sya
1.2.4; Yuktidiipikaa ad Saankhyakaarikaa 2;
Saardhatri"satikaalottaravrtti ad 8.12;
Nyaayavaarttikataatparya.tiikaa ad Nyaayasuutra 1.2.1 etc.):

arke cen madhu vindeta kimartham parvata.m vrajet|

i.s.tasyaarthasya sampraaptau ko vidvaan yatnam aacaret||

Often Mss give the variant akke for the first word.  Apte (and not
Monier Williams) defines akka as  `[a] corner of a house'; but he
cites no instance of its use other than the first paada of the above
verse (which he also cites under arka).  Does akka occur elsewhere,
or is Apte's an ad hoc explanation  of a corruption of the word in
this verse?

Should one assume that arka is correct and that it refers to the tree 
(?Calotropis Gigantia (Linn) R.Br ex Ait.)?  Is honey never found in 
such trees?  Do they grow in the plains and not in mountain regions?
I think that there is an article about this, but I don't remember 
the details. I should be grateful, if someone could offer 
me some help. 
Dominic Goodall.