A tetraploid plant of Dendrobium Samarai (D. stratiotes x D. antennatum) arose spontaneously among diploid offspring. This tetraploid section, K1315-60, has two sets of chromosomes each of D. stratiotes and D. antennatum and produces flower parts that are slightly broader and of heavier substance than those of its diploid counterpart.

K1315-60 was crossed on February 27, 1995, to amphidiploid D. Caesar, the parent plant of the seed-propagated cultivar D. Lim Chong Min (UH1382) released earlier. Seeds were germinated in June 1995, and most of the seedlings began to flower about 27 months later. The flowers of the cross (UH1577) are light lavender (RHSCC 81D), in contrast to the purple (RHSCC 81A) flowers of D. Caesar and the white-green flowers of D. Samarai. The lavender color often fades with age, resulting in yellow-green petals and slightly variable colors within the same plant. The broad mid-lobe of the lips is light purple with dark purple veins. The petals of UH1577 are upright and twisted 180° and are light purple on a yellow-green base. The majority of the flowers were produced between December and May and lasted three to four months on the plants (see chart). Because of the long life of the flowers, the plants remained attractive through June and July despite the scarcity of new blooms during these months.

Dendrobium Caesar x D. Samarai was registered with the International Orchid Registrar as D. Lorrie Mortimer, after the wife of the president of the University of Hawaii. The attributes of D. Lorrie Mortimer are attractive light lavender flowers, relatively uniform seed-propagated offspring, short stature, excellent keeping quality of sprays on plants, and desirable flowering season from December through May. Seed pods of D. Lorrie Mortimer have been released to Dendrobium growers’ associations in Hawaii as a seed-propagated flowering potted-plant cultivar. Dendrobium Lorrie Mortimer should complement white-flowered D. Samarai (UH988) purple-flowered D. Lim Chong Min (UH1382) during the period of good demand for potted plants from December to June.

Flower length

2.8 ± 0.2

Flower width

2.0 ± 0.3

Petal length

1.9 ± 0.2

Petal width

1.2 ± 0.2

Dorsal sepal length

1.1 ± 0.1

Dorsal sepal width

0.4 ± 0.1

Pedicel length

1.0 ± 0.1

Scape length

3.2 ± 0.6

Raceme length

7.0 ± 1.0

Flowers per spray (number)

5.7 ± 1.0

Bud drop (%)

5.7

Pseudobulb height at first flower

10.2 ± 3.9

Pesudobulb height in June 1998

18.3 ± 4.2