dodendrons may be
| | |divided into several groups
| | |according to parentage. Of
| | |these groups by far the
| | |most familiar is the one
| | |that has originated through
| | |the crossing and
| | |intercrossing of the
| | |Himalayan R. arboreum
| | |with the American R.
| | |catawbiense, the Caucasian
| | |species R. caucasicum, or
| | |the European and Asiatic
| | |ponticum. This hybridising
| | |has been progressing for
| | |half a century or more,
| | |and the parentage is
| | |plainly seen in the
| | |offspring. Thus where R.
| | |arboreum asserts itself
| | |most strongly we find rich
| | |red flowers and leaves
| | |with a silvery
| | |under-surface. Where R.
| | |catawbiense is most in
| | |evidence the leaves are
| | |large and handsome, deep
| | |green, and softer to the
| | |touch than R. arboreum,
| | |while the clusters are
| | |often of great size, the
| | |flowers prettily spotted,
| | |and the plants of
| | |exceptionally good habit.
| | |For very cold districts the