I am looking for cuttings or plants of Selenecereus grandiflorus. Also looking for Ranunculus bulbosus bulbs
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As you were very specific about the two species mentioned, the latter, Bulbous or St. Anthony’s Turnip (Ranunculus bulbosus), is part of the Buttercup or Ranunculus family. Although it is “bulbous”, it’s not actually a bulb. The bulb refers to the swelling at the base of the plant, which distinguishes it from other butter cup that are commonly found in open areas. It should be available from on-line suppliers, and it may be found in nurseries that do not operate out of home and hardware stores.
More information: https://www.botanical.com/botanical/mgmh/b/butcup97.html
The former, Sweet-Scented or Vanilla Scented Cactus (Selenecereus grandiflora) is a night blooming tropical found in the West Indies, Mexico and parts of South America. Cactus are rarely supplied by nurseries, yet there are nurseries that specialize in certain plants, including cacti.
More Information: https://www.botanical.com/botanical/mgmh/c/cernig48.html
Both the plants you have inquired about have herbal or medicinal value. Either may be available at growers that specialize in herbs.