Xylem cells are elongated cells with lignified secondary thickening of the cell walls. Xylem cells are specialised for conduction of water, and first appeared in plants during their transition to land in the Silurian period more than 425 million years ago (see Cooksonia). The possession of xylem defines the vascular plants or Tracheophytes.
hobo. a hobo is an itinerant worker, a career which sprang up during the depression. A hobo, unlike a bum or a tramp, is more than willing to work, but mostly for a short duration, as their main impetus is travel, the love of the journey above the actual destination.
A âGoboâ is a small stencilled circular disc, and used in lighting fixtures to create a projected image or pattern.The term Gobo is short for âGo Between Opticsâ, describing the location where it needs to be positioned in the light path of a lighting fixture.Whilst Goboâs are not a new technology they are still being used on events the world over.he possibilities are endless but first we look at the history of the gobo and what you need to know before creating a customised gobo. 1  Audio Visual Discipline: Lighting for events. 2  Audio Visual Event Category: AV Effect. 3  AV Jargon: Gobo, Batman Signal.