Luke 17:6 says,

 So the Lord said, “If you have faith as a mustard seed, you can say to this mulberry tree, ‘Be pulled up by the roots and be planted in the sea,’ and it would obey you.

                                     NKJV

 Mustard Seed Plants

Matthew 17:20 says,

 So Jesus said to them, “Because of your unbelief;or assuredly, I say to you, if you have faith as a mustard seed, you will say to this mountain, ‘Move from here to there,’ and it will move; and nothing will be impossible for you.

                                     NKJV