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Key to Orobanche

Orobanchaceae

Orobanche

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1 Flowers solitary on a long pedicel (appearing as a scape, the true stem entirely underground or nearly so)
1 Flowers several-many, sessile or subsessile in a dense spike.
  2 Calyx 5-lobed, the lobes subequal, all well-developed
  2 Calyx 2-4-lobed, rarely 5-lobed, but then the fifth lobe minute and much smaller than the other lobes.
    3 Calyx divided to the base into 2 lateral halves, these usually 2-lobed, the 4 lobes long-attenuate or caudate; stem unbranched
    3 Calyx tubular, with 4 (-5) lobes about the length of the calyx tube; stem branched (except in depauperate individuals)