An expensive one, mentioned in the New Testament as a specifically costly thing -- to continue may theme from last week of Biblical plants. The identification of the modern plant with the ancient substance is not certain, but it seems very likely. The plant is in the valerian family, and its name comes from Medieval Latin spīca nardī, spiked nard, the latter half of which traces back through Latin and Greek to some Semitic root, possibly Hebrew nērd. The North American plants also called spikenard are unrelated, being members of the ginsing family.
First they bring me frankincense, then myrrh, then spikenard -- I just want a clean nappy so I can change this dratted baby!