Further Notes on an Artificial Rubus.
Hybrid (× Rubus parvicoloratus Vida).
[Read before the Philosophical Institute of Canterbury, 1st August, 1928; received by Editor, 20th September, 1928; issued separately, 30th November, 1928.]
A description of the F1 seedlings of this artificial hybrid was given in Trans. N.Z. Inst., vol. 58, 1927, pp. 51–54. The horticultural value of the hybrid was stated in The Gardeners' Chronicle of 19th November, 1927, p. 405, and its points of difference from the well-known × R. Barkeri mentioned. Reference was there also made to the wild hybrid plant (X R. Mackayi) discovered near Notown by Dr. W. Mackay, of Greymouth. This latter plant resembles × R. Barkeri rather closely. A third wild hybrid plant was grown for some time on the Nelson Rock Garden Society's rockery. A cutting from this has been established by Dr. L. Cockayne in his garden at Ngaio. The original plant possibly came from the Styx valley, but I have been unable to obtain exact information. This hybrid very closely resembles my artificial one. Should its origin from a wild hybrid plant be definitely shown I propose for it the name × R. Hollowayi, after Dr. J. E. Holloway, whose botanical work on the west coast of South Island is so well known.
A comparison of the three wild hybrids with the artificial hybrid strongly suggests that both × R. Barkeri and × R. Mackayi are derivatives of the cross R. australis × parvus, and that × R. Hollowayi is derived from R. parvus × schmidelioides. The male parent of my hybrid was R. schmidelioides var. coloratus. This jordanon I regard as so distinct from what has been considered R. schmidelioides proper that it should have specific rank. It is by no means certain, however, that var. coloratus is not really Cunningham's R. schmidelioides. His description (Ann. Nat. Hist., vol. 3, 1839, p. 568) includes “foliolis omnino ternatis rugosis venosis subtus (discoloribus) valde ferrugineo-tomentosis.” This certainly does not fit the jordanon with orbicular-ovate, glabrous leaves.
A comparative table of the vegetative characters of the adult hybrid and its parents is here given, as it may be a long wait till the hybrid plants flower. It is of interest to note that the succession of leaves on lateral branchlets of the adult is from unifoliate, through irregularly bifoliate and trifoliate forms, to the fully trifoliate leaves of the final stage, thus recalling the forme passed through by the seedling plants as a whole.
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|Characters||R. schmidelioides var coloratus (Plant used as ♂ parent).||× R. parvicoloratus Vida.||R. parvus (plant used as ♀ parent).|
|Growth-form||large scrambling liane||shrub, with stems prostrate and non-rooting||shrub, with far - creeping and rooting stems|
|Young branchlets||pubescent; prickles numerous; brownish green in winter||glabrous or nearly so; no prickles; golden brown in winter||glabrous; no prickles; chestnut brown in winter.|
|Leaves: nature||predominately 3-foliate||3-foliate||simple|
|Size||central lflt ± 2.5 cm. by 5 cm.||central lflt ± 1.5 cm. by 6 cm.||± 1.75 cm. by 8 cm.|
|shape||central lflt ovate-oblong, acute||central lflt linear - lanceolate, acute||linear-lanceolate, acute|
|petioles||pubescent, prickly||with few hairs, prickly||with very few hairs, not prickly|
|upper surfaces||somewhat rugose; with scattered hairs||not rugose; glabrous or nearly so||not rugose; glabrous or nearly so.|
|lower surfaces||whitish, tomentose||pale green, glabrous||pale green, glabrous|
|margins||coarsely and irregularly toothed, teeth blunt||serrate-dentate, somewhat irregularly, teeth sharp||regularly and sharply dentate.|