Quantitative and qualitative data are presented for wood anatomy of 35 collections representing 22 Old World species of Ephedra; the survey of bark and pith anatomy is based on some of these species. Character-state ranges similar to those of the New World species are reported, although more numerous species show vessel absence in latewood. Little diminution in vessel diameter or density occurs...

The formation of tumors in tissues of higher plants by the crown-gall organism, (Phytomonas tumefaciens), is influenced by several factors. First, the bacteria themselves must be virulent. Avirulent strains of the crown-gall organism will not produce a gall in susceptible tissue unless that tissue is also stimulated by a growth hormone (1, 10) or by products from a gall produced by fully virule...

With at least 60 independent origins spanning monocotyledons and dicotyledons, the C4 photosynthetic pathway represents one of the most remarkable examples of convergent evolution. The recurrent evolution of this highly complex trait involving alterations to leaf anatomy, cell biology and biochemistry allows an increase in productivity by ∼ 50% in tropical and subtropical areas. The extent to w...

BACKGROUND AND AIMS Plants of Ephedra normally have vessels, but are known to become nearly vessel-less in some alpine localities. Previous studies implied that wood formation in Ephedra differs fundamentally from that in dicotyledons in which vessel-bearing and vessel-less taxa are systematically distinct. Using E. pachyclada in the Mustang district of Nepal, growing in an altitudinal range of...

Paleobotanists have long built leaf climate models based on site mean of physiognomic characteristics woody dicotyledons species (WDS) for estimating past climate. To explore the potential order Ericales in paleoclimate, we developed two linear each climatic factor. One is WDS, and other both WDS characters (WDS-E). We found that, compared with models, WDS-E improved greatly annual precipitatio...