Table 1.

Mean and range of xylem pressure at 75% loss of hydraulic conductivity (P75)

Species (year)	n	Mean	Standard error	Minimum	Maximum	Variance
2002 (*)
H. anomalus	9	–2.663	0.133	–3.45	–2.15	0.142
H. deserticola	9	–3.421	0.250	–4.80	–2.90	0.438
2003 (ns)
H. anomalus	8	–2.838	0.189	–3.65	–2.15	0.287
H. deserticola	12	–2.817	0.173	–3.90	–2.00	0.359

P75 was estimated for each individual then pooled for all native H. anomalus and H. deserticola collected in 2002 and 2003. Species means differ significantly in 2002 but are not significant in 2003. Note that native plants were sample at the same time in 2002 but not in 2003. See Materials and methods for details.