Sinojackia xylocarpa Hu

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Credits

Alan Elliott (2019)

Recommended citation
Elliott, A. (2019), 'Sinojackia xylocarpa' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/sinojackia/sinojackia-xylocarpa/). Accessed 2020-09-23.

Genus

Common Names

  • Jack Flower
  • Jack Tree
  • Chinese Jack Tree

Glossary

ellipsoid
An elliptic solid.
Extinct
IUCN Red List conservation category: ‘there is no reasonable doubt that the last individual [of taxon] has died’.
ovoid
Egg-shaped solid.

References

There are currently no active references in this article.

Credits

Alan Elliott (2019)

Recommended citation
Elliott, A. (2019), 'Sinojackia xylocarpa' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/sinojackia/sinojackia-xylocarpa/). Accessed 2020-09-23.

Trees or shrub to 7 m tall. Branchlets densely grey-brown stellate pubescent. Leaves on fertile branches ovate, 2–5 × 1.5–2 cm, base rounded to shallowly cordate; leaves on sterile branches obovate to elliptic, 3–9 × 2–5 cm, base rounded to cuneate; upper leaf surface glabrous with sparse stellate pubescent on midrib, lower surface sparsely stellate pubescent, margin serrate, apex acute, veins 5–7 pairs; petiole c. 5 mm. Inflorescences 3–5-flowered, 3–5 cm long; pedicel c. 5 cm. Flowers pendulous. Calyx tube c. 4 mm, densely stellate pubescent; teeth 5–7, lanceolate. Corolla lobes oblong-elliptic, 8–12 × c. 6 mm, apex obtuse. Filaments c. 4 mm, sparsely stellate pubescent. Style c. 8 mm. Fruit ovoid including a conical beak, 1.8–2 × 0.8–1.5 cm, rounded base. (Hwang & Grimes 1996).

Distribution  China Jiangsu

Habitat Forest edges; 500–800 m.

USDA Hardiness Zone 6a-9b

RHS Hardiness Rating H4

Conservation status Vulnerable (VU)

Taxonomic note Most easily differentiated from Sinojackia rehderiana in fruit. S. xylocarpa fruits are ellipsoid in shape and greater than 2 cm long, S. rehderiana fruits are ovoid and less than 2 cm long.

This species was introduced to cultivation in the 1930s by Professor H. H. Hu who first discovered and described the species (Arboretum Foundation 1980). However, it appears never to have been particularly common in cultivation and presently only a handful of gardens grow this species, preumably from more recent collections. Specimens can be seen at Kew, the Sir Harold Hillier Gardens, and the Arnold Arboretum. This species is in the horticultural trade in Europe and North America.

In the wild this species has a very narrow distribution and is threatened due to being cut for firewood. Its rarity has been evident since it was discovered as Bean relates: ‘The type-specimens were taken from a single tree growing at a resort in the suburbs of Nanking known as the Sen-Tai-Tung cave. Shortly afterwards this tree, the only one found, was cut down during roadmaking, and the seeds that had been distributed to botanical institutions in Europe and America were immature, and failed to germinate. Thus, for a brief space, it seemed as if this new genus was extinct. Then, in 1933, S. xylocarpa was found to be quite common in the hills of Pukow, on the other side of the Yangtse from Nanking, and was successfully introduced to cultivation later in the decade’ (Bean 1981b).


'Lagrima'

This cultivar is a fastigiate form selected by Highland Creek Nursery in Fletcher, North Carolina. This cultivar is available in the horticultural trade in the US and is occassionaly listed in Dutch nursery catalogues. (Hatch 2018-2020).


'Linda Carol'

This is a weeping and spreading form selected by Highland Creek Nursery in Fletcher, North Carolina, USA. So far it appears to be restricted to the horticultural trade in the USA. (Hatch 2018-2020).

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