Eliminating these variations, three jordanons can be identified on leaf shape and the presence of marginal incisions (fig. 1). The basis is partly geographical as indicated by the following table:—
Fig. 1.—Hebe colensoi. Leaf forms of Jordanons. 1—Taruarau. 2.—Kuripaponga. 3—Rangitikei.
Fig. 2—Changes in Leaf Form from base to tip of Shoot. Jordanon 1 (Cultigen).
[The section below cannot be correctly rendered as it contains complex formatting. See the image of the page for a more accurate rendering.]
|Margin Entire.||Margin Incised.|
|Leaf obovate. Jordanon 1.||Leaf elliptic.||1-10 pr. general. Jordanon 2.||0-3 pr. occasional.|
|Makahu||0||14||50 + 17||19|
|Western.||Rangitikei and Mangamaire||3||93||4|
These figures can only be taken as rough approximations for the colonies of the eastern area, though the totals for the eastern and western areas represent large and comparable numbers.
The first column represents a jordanon with obovate entire leaves most strongly represented at the Taruarau bridge, and probably occurring all through the eastern area. It comes true from seed and agrees with the Kew specimen of V. hillii Col. It does not appear to be present in the western area, the figure in that column covering variations in leaf form in specimens otherwise recognisable as a western jordanon.
Column 2 covers a well-marked jordanon, of the Western area, distinguished by the larger size of fully-developed plants and drooping branch tips (fig. 4). The leaf has a characteristic shape—Cheeseman's “oblong-lanceolate” perhaps describes it better than “elliptic.“It does not occur in the eastern area; the figures in that column certainly refer to hybrids between another Eastern jordanon and that of column 1.
Column 3 represents the jordanon, preponderant at Kuripapanga and the Makahu and present throughout the Eastern area. It is distinguished by much-incised elliptical leaves. Its seedlings are noticeably slower than those of the other jordanons to assume the glaucous colour of the adult form and epharmonic variation is more marked, the extreme form having a linear-oblong leaf, only slightly incised.
The lesser figure against the Makahu colony represents a group with strongly serrated rather than incised leaves, whose affinities are not obvious. The colony is a comparatively small one, outside the main area of distribution, and having only recently been located, breeding experiments have not yet had time to give any results.
The fourth column does not lend itself to ready analysis, but consists partly of exposed epharmones of the third jordanon, and almost certainly a number of cases of occasional juvenile toothing persisting in adult forms of both the first and second jordanons.
A large proportion of the fourth column together with column 2, however, must be referred, in the eastern area to the existence of hybrids between jordanons one and three. Except in the Makahu a fair range of forms in leaf shape and the development of incisions occur in each colony, and, though jordanon one has not been collected at Kuripapanga, forms closely approaching it have been.
Hybridization with other species is suspected in one example at the Taruarau, but cultivation from seed has given no definite proof of this.
In the Dominion Museum Petrie's No. 6 from the Upper Rangitikei ford, “identified at Kew in 1891 as V. colensoi,” appears to be a hybrid, its blackness in drying suggesting Hebe buxifolia as a possible parent.