Mistletoe species can be hemiparasites or holoparasites. A hemiparasite, such as Viscum album, possesses green leaves with functional chloroplasts and can perform photosynthesis to produce its own organic nutrients. However, it lacks a root system to absorb water and mineral ions from the soil. To survive, the parasite grows a specialized tissue called a haustorium that penetrates the host plant's stem to access its transport systems. Which of the options describes the primary host tissue that the haustorium of V. album must connect to in order to obtain the resources it cannot absorb from the environment?