Mas, se no texto está escrito daffodil e depois Narcissus, pensei que tinha uma diferença. Daffodil é Narciso Silvestre?
Obrigada

   In English, generally speaking everybody says daffodil, not Narcissus (Narciso in Portuguese).   Of course people that deal with plants and flowers know and  use the word Narcisus as you can see in this site:

http://www.teleflora.com/about-flowers/daffodil.asp

  Even so, you may have noticed that they used daffodils 10 times, and narcissus 03 times, this speaks volumes...

   And in general they don´t make the distinction if the daffodil is "silvestre" (wild) or not.

   Generally, I said, there are guys that will name them (as you saw in the links I divulged before).  

http://www.daffodilusa.org/daffodils/faq.html

What is the difference between daffodils and narcissus?
None. The two words are synonyms. Narcissus is the Latin or botanical name for all daffodils, just as ilex is for hollies.
Daffodil is the common name for all members of the genus Narcissus, and its use is recommended by the ADS at all times other than in scientific writing.

   This goes back to the beggining of taxonomy, as can be seen, Linneus wrote in Latin, the standard intellectual language of his time. 

    Portuguese and Spanish are languages that branched out from Latin, hence we call it "narciso" and we can afford the luxury of classifying them (at least in Brazil), because we don´t have the climate to all of them, only some types.  I think that´s why. 

   Anyway, you can in a conversation explain that your daffodils are the yellow, white ones, or any other classifiction, provided that you and the listener/reader shares this knowledge.

   Again, in general, English speakers kis (keep it simple); they say daffodil.