Rusk

Synonyms

de Rush, de Rusk (sec. Cottin 2002)

Cultivar or taxon

Citrus x aurantium L., pro sp. [Sweet Orange Group] X Citrus trifoliata L. (sensu Mabberley 2004, Bayer et al. 2009); Citrus sinensis (L.) Osbeck x Poncirus trifoliata (L.) Raf. (sensu Swingle and Reece 1967; sensu Tanaka sec. Cottin 2002; sec. NPGS/GRIN 2010)

Origin

Hodgson (1967) noted that: "Rusk, a Ruby orange and trifoliata hybrid, is one of the oldest citranges, having been created by Swingle in 1897 and described and released in 1905 (Webber and Swingle). It was named in honor of J. M. Rusk, the first Secretary of Agriculture of the United States."

Description

Crown compact or dense, not weeping. First-year twig surface glabrous; second- or third-year twig surface striate; thorns straight; prickles absent or not persistent. Petiole glabrous, length medium, long or very long; wings medium, adjoining the blade. Leaflets one or three, margin crenate/crenulate or bluntly toothed, rachis wings absent, shade leaflet blades weakly conduplicate, sun leaflet blades weakly or strongly conduplicate. Scent of crushed leaflets spicy, peppery, or not scented. Fruit broader than long; rind yellow (7-10), yellow-orange (11), orange (12), or red-orange (13); rind texture slightly rough (4-5); firmness leathery; navel absent; flesh orange or yellow; taste sour.

Hodgson (1967) provided the following additional notes on the cultivar:

"Fruit rather small, oblate to spherical; smooth and virtually glabrous; color deep orange with reddish flush. Rind thin and tightly adherent; segments about 10. Flesh color orange-yellow; very juicy; flavor sprightly acid and only slightly bitter. Seeds few and highly polyembryonic. Early in maturity.

Tree vigorous, tall-growing, productive, and hardy; foliage evergreen to semi-deciduous and dense, consisting of moderately large trifoliolate leaves."

Notes

Hodgson (1967) additionally noted that:

"The tree is an attractive ornamental and the fruit is juicy and approaches edibility more closely than most citranges. Its low seed content mitigates against use as a rootstock.

Rusk is currently of greatest interest and importance in Florida."

References

Bayer, R.J., D.J. Mabberley, C. Morton, C.H. Miller, I.K. Sharma, B.E. Pfeil, S. Rich, R. Hitchcock, and S. Sykes. 2009. A molecular phylogeny of the orange subfamily (Rutaceae: Aurantioideae) using nine cpDNA sequences. American Journal of Botany 96: 668–685.

Cottin, R. 2002. Citrus of the World: A citrus directory. Version 2.0. France: SRA INRA-CIRAD.

Hodgson, R.W. 1967. Horticultural varieties of Citrus. In: Reuther, W., H.J. Webber, and L.D. Batchelor (eds.). The Citrus industry, rev. University of California Press. http://lib.ucr.edu/agnic/webber/Vol1/Chapter4.html.

Mabberley, D.J. 2004. Citrus (Rutaceae): A review of recent advances in etymology, systematics and medical applications. Blumea 49: 481–498.

Swingle, W.T. and P.C. Reece. 1967. The botany of Citrus and its wild relatives. In: Reuther, W., H.J. Webber, and L.D. Batchelor (eds.). The Citrus industry. Ed. 2. Vol. I. University of California, Riverside. http://lib.ucr.edu/agnic/webber/Vol1/Chapter3.html.

Webber, H.J. and W.T. Swingle. 1905. New citrus creations of the Department of Agriculture. U.S. Department of Agriculture Yearbook 1904: 221–240.

Resources

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