Figure 31. — Winterfat utricle showing dense, long, silky hairs. (Scale in mm.) 



Winterfat is remarkably resistant to drought, and even on dry sites will produce 

 seed in the third and fourth year. On favorable sites, plants have produced some seed 

 in their first year of growth. The species has a deep taproot and numerous extensive 

 lateral roots. The plant may appear dead after unusually dry years, but it normally 

 recovers after rain. It exhibits strong reproductive qualities; however, establishment 

 from artificial seeding has often been unsuccessful because seedlings are highly 

 sensitive to frost damage. ,. 



Hybridization: The different ecotypes (forms) of winterfat not only show wide 

 variation in stature, but also in seed production, seed size, seedling germination 

 and vigor, pubescence on fruit and seed, and tolerance to varying pH in soils. 



A more woody, somewhat spinescent form of winterfat (C. lanata ssp. subspinosa) 

 occurs on rocky hills in southern Utah, Arizona, California, and Mexico. It apparently 

 is the only form present in southern Arizona. This subspecies shows intergradation in 

 all characteristics with typical winterfat (Kearney and Peebles 1960). Possible prod- 

 uction of superior strains through hybridization and selection appears excellent because 

 of the wide variation between ecotypes and the natural hybridization with subspecies 

 subspinosa. Riedl and others (1964) found that parts of female plants covered with 

 muslin bags did not set seed, but uncovered parts did; so winterfat appears to be wind 

 pollinated. Thus, one should be able to bag a branch bearing pistillate flower buds for 

 use in hybridization. The desired pollen could be introduced when the flowers are in 

 bloom and the stigmas receptive. A limited number of viable seeds have been obtained by 

 pollinating fourwing saltbush pistillate flowers with winterfat pollen (table 1). None 

 of the seedlings have survived. Winterfat is diploid with a chromosome number of 

 2n = 18 (Bassett and Crompton 1971). 



25 



