Garden, 2006 ), and the U.S. Department of Agriculture (USDA) National Plant Germplasm System ( USDA, 2006 ). Taxonomy of Taxodium Baldcypress, pondcypress, and montezuma cypress are three taxa recognized historically in the genus Taxodium . Baldcypress
Geoffrey C. Denny and Michael A. Arnold
Geoffrey C. Denny* and Michael A. Arnold
An experiment was initiated to evaluate the effects of previously recommended seed treatments for baldcypress [Taxodium distichum (L.) Rich.] or pondcypress [Taxodium distichum (L.) Rich. var. imbricarium (Nutt.) Croom] on Montezuma cypress [Taxodium distichum (L.) Rich. var. mexicanum Gordon], and to determine which, if any, provided optimum germination. Factorial combinations of seed treatments and stratification (2 °C for 0, 45, or 90 d) were applied to seeds of Montezuma cypress. Treatments included: 1) 90% ethanol 5 min soak, 2) ethyl ether 5 min soak, 3) 100 mg·L-1 citric acid 48 h soak, 4) mechanical scarification, 5) five hot water baths (42 °C) allowing the water to cool to room temperature between baths, and 6) a non-treated control. Three more seed treatments consisted of water soaks at room temperature (25 °C) for 0, 45, or 90 d. Seeds were germinated on moist filter paper in a growth chamber with a 12-h day/night photoperiod at a constant 25 °C. Data was collected daily for 14 d and then weekly for the following 4 wks. Radicle elongation of 1 cm was considered germination. Without stratification, 100 mg·L-1 citric acid and the hot water bath treatments were significantly different from other treatments by 7 d, though not from each other, with a mean cumulative germination of 15.6% and 12.2%, respectively. By 14 d, the 100 mg·L-1 citric acid treatment differed only from the ethyl ether wash attaining 28.9% and 14.4% germination, respectively. There were no other statistically significant differences observed among any other treatments without stratification. Germination percentages were low,<30%, without stratification. Effects of additional stratification will also be discussed.
Rolston St. Hilaire
Indigenous stands of Taxodium mucronatum Ten. are found in North and Central America, but relatively little is known about the propagation of the species. Progeny from one tree in the Mesilla Valley near Las Cruces, N.M., and from two trees in the Gila National Forest, New Mexico, were observed to be relatively cold-hardy. I initiated this research to find the best conditions for asexual and sexual propagation of those three trees. Terminal softwood cuttings were collected on 16 Oct. 1998 from a half-sibling of the Mesilla Valley tree, and from two half-siblings from the trees in the Gila National Forest. Cuttings were treated with two concentrations of IBA and rooted under intermittent mist in the greenhouse for 13 weeks. Cuttings taken from the Mesilla Valley source and from one of the half-siblings from the Gila did not root. The other half-sibling plant from the Gila showed 82% rooting when cuttings were treated with 8 g IBA/kg. Fifty percent of cuttings rooted when they were treated with 3 g IBA/kg. Root number and root length were greatest for cuttings treated with 8 g IBA/kg. Replication over time will determine whether stock plant environment and the time of taking cuttings affect rooting. Strategies that optimize seed germination and seedling development of asexually and sexually propagated material are being evaluated.
Lijing Zhou, David L. Creech, Ken W. Krauss, Yin Yunlong, and David L. Kulhavy
three separate species of Taxodium : Taxodium distichum (baldcypress), T. ascendens (pondcypress), and T. mucronatum (Montezuma cypress). Although the taxonomic relationships among these three species, or varieties, of Taxodium remain a source
Geoffrey C. Denny, Michael A. Arnold, and Wayne A. Mackay
Gordon (Montezuma cypress) remains semievergreen ( Arnold, 2002 ). It is an extremely long-living tree with a lifespan of up to 700 years ( Cox and Leslie, 1988 ). All of these factors allow T. distichum to tolerate many environmental stresses, making
D. Creech and Yin Yunlong
There are three botanical varieties associated with the genus Taxodium: 1) Baldcypress (BC) = Taxodium distichum (L.) Rich.var. distichum, 2) Pondcypress (PC) = T. distichum var. imbricarium (Nutt.) Croom and 3) Montezuma cypress (MC) = T. distichum var. mexicana Gordon. Taxodium hybridization promises to combine the best characteristics of superior parents. In 1988, clones T302 (a BC × MC F1 hybrid), T401 (PC × MC), and T202 (PC × BC) were selected in China primarily for growth rate and tolerance to alkaline and salt-rich coastal floodplains. T302 is recommended in China for soils with pH 8.0∼8.5 and salt concentrations <0.2%. Other attributes of T302 included 159% faster growth than BC, good columnar form, longer foliage retention in fall and early winter, and no knees. T302 has been in the USA since January 2002 and is currently under evaluation in over 30 locations in southern USA. The clone was named `Nanjing Beauty' in 2004 as a cooperative introduction of the SFA Mast Arboretum and Nanjing Botanical Garden. In March 2005, the SFA Mast Arboretum received two new clones from China. T140 and T27 are considered more evergreen than T302 and both demonstrate strong salt tolerance. The clones were selected from a field population of T302 × TM—with strong TM characteristics and improvements in growth rate, salt tolerance, form and vigor. T140 grows faster than T27, which produces a wider profile. The foundation of the most recent selections comes originally from crosses made by Professor Chen and Liu in 1992 at the Nanjing Botanical Garden. Pollen from TM was applied to a female T302 and fifteen selections were made in 1995. The main characteristics for selection were 1) fast growth rate, 2) dark green color during the growing season and a red-orange leaf color in the fall, and 3) evergreen leaves. In 2006 or 2007, the results from T140 and T27 will be reported and registered with the Chinese Forestry Department. It will be at least five years before T140 and T27 enter commerce. In June, 2005 there were <100 each of these two clones. T118, T120 and T149 have already been registered with the Chinese Forestry Department at the provincial level, while T302 has been registered at the national level.
Qin Shi, Yunlong Yin, Zhiquan Wang, Wencai Fan, and Jianfeng Hua
. mexicanum (Carriere Gordon) (Montezuma cypress-MC) and T . distichum var. imbricarium (Nutt.) Croom (pondcypress-PC) ( Adams et al., 2012 ; Creech et al., 2011; Denny and Arnold, 2007 ). For the purpose of this study, we have accepted the
Garry Vernon McDonald, Geoffrey C. Denny, Michael A. Arnold, Donita L. Bryan, and Larry Barnes
designates Taxodium distichum var. mexicanum (also known as Montezuma Cypress), D designates T. distichum var. distichum , and I designates T. distichum var. imbracarium . Selections from central Texas were from along spring-fed riparian areas
Andrew R. King, Michael A. Arnold, Douglas F. Welsh, and W. Todd Watson
( Arnold, 2008 ; Dirr, 2009 ). The genus Taxodium Rich. includes three different varieties: baldcypress [ Taxodium distichum (L.) Rich. var. distichum ], pondcypress [ Taxodium distichum var. imbricarium (Nutt.) Croom], and Montezuma cypress
Junqin Zong, Yanzhi Gao, Jingbo Chen, Hailin Guo, Yi Wang, Fan Meng, Yiwei Jiang, and Jianxiu Liu
baldcypress ( Taxodium distichum ) and montezuma cypress ( Taxodium mucronatum ) in surviving waterlogging. In enzymatic defense systems, SOD plays a central role in catalyzing the dismutation of O 2 ·- to H 2 O 2 and O 2 ( Bowler et al., 1992 ). In