Many of the complex traits related to sexual reproduction , photosynthesis , and other plant characters , evolved first in charophyceans . Analysis of cpDNA ( chloroplast DNA ) shows that characteristics of plant chloroplasts evolved first in the charophycean genera Staurastrum and Zygnema . Many of the complex traits related to sexual reproduction , photosynthesis , and other defining characteristics of plants evolved first in charophyceans ; analysis of cpDNA ( chloroplast DNA ) , for instance , reveals that many characteristics of plant chloroplasts evolved first in the charophycean genera Staurastrum and Zygnema .