The order of gnetales

Of the three peculiar genera belonging to this order only one, Ephedra, occurs in the United States. Welwitschia is found only in Damaraland, South Africa, and Gnetum is tropical and subtropical. Gnetum thrives in the greenhouse, but the other two have not been cultivated successfully. All show vessels in the secondary wood, an angiosperm character. The strobili can be fixed in formalin-alcohol- acetic acid, but in Ephedra the dry chaffy scales must be dissected away before completing the dehydration and infiltration with paraffin.

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