I have a couple of questions that have been raised by the grammar section of my Collins Latin Dictionary. I crossed referred with Tanaquil's lessons and did not find the same points referred to. I would usually print the latter off as I don't like reading from the screen for too long but my printer's faulty.

Anyway Collins gives amongst its 1st declension examples 'crambe (-es)'(f)= cabbage, and it declines consistent with say terra (-ae) except in the singular as follows:
Nom - crambe
Acc - cramben
Gen - crambes

Is this 1st group of nouns i.e., (f) -e, -es a rarity, and typically only feminine?

Second issue concerns 3rd declension Group IV which Collins heads up exactly as follows: 'Group IV: Greek nouns'. It then goes on to give the examples of aer, heros, Pericles, Naias, poema. Surely this group doesn't only refer to Greek nouns or derivatives?

Sorry if I'm trying to run before I can walk or I've missed something in the SLL lessons!*S*