Yellow blooms indicates either a tuberous type, an African rhizomatous, or a Hiemalis (usually treated as an annual). I would do an image search to find the one you do have and go from there.

The spotted cane is another matter. If you have a fast drying soil mix, you should thoroughly water your begonia when it dries some and not water again until it dries again (rule of thumb is to test the top 1" with your finger to see if it is dry before watering again but if you have a fast draining mix you should be okay without doing this test - I rarely do this). During warm weather I would move it outdoors to get as much warmth and bright light (not afternoon sun) as possible. You can keep it indoors as well but they seem to do a lot more growing being outdoors. Use a slow release fertilizer

Also make sure your pot is not too large for the plant.

Thank you for your response!! I'm re-posting an email that sent I to your email just in case you didn't receive it. Yes, the one with the yellow blooms is not the cane variety but it is losing leaves as well. The one that dropped all the leaves this morning --more or less all of a sudden--was the spotted angel wing. I have three different begonias planted in a large container together all outside. I don't know what the third one is, but it's short and kind of clumped up, reddish leaves growing close to the soil surface--I think it's called a begonia :dewdrop." seems to be doing well. I probably put them all together in a too big pot I suppose and possibly overwatered after a recent short heat spell. Can you tell me why the container size matters? Is it because there is too much soil that stays moist for too long? Do you think I should repot the spotted angel wing in a smaller container with a faster draining soil? Maybe I can save it. Again, thanks so much for your reply.