This bryophyllum is probably bryophyllum x houghtonii, but there are several similar looking varieties of bryophyllum. Their common names are telling, however. Bryophyllum x houghtonii is known as ‘hybrid mother-of-millions.’ Common names for other bryophyllums include ‘mother-of-millions,’ ‘prolific mother-of-millions,’ and ‘mother-of-thousands.’
Such names make it no surprise that bryophyllums are invasive. They’re also poisonous to both livestock and humans, which is problematic since these photos were taken at Pu’u Wa’awa’a, in an area occupied by sheep and cattle.
For more information about Pu’u Wa’awa’a and its trails, go to puuwaawaa.org.