Crime Scene Botanicals

Long ago the court wouldn't allow the people that works with plants and or collects plants for evidence wasn't able to be used cause there's so many plants around the world, how were they going to be able to identify where the person was at the time of the crime. For an example two kids were found buried under a tree and the people found seeds in the kids stomach and when they found out that the seeds were poisonous. The stepfather called a missing report to the police and they got the man sentenced two life sentence because the seeds on the blanket and the seeds on the father was a match. He even lied his way out saying he had these types of seeds on this farm he owned and none was to be found. Now a days they use plants to use in court unless it doesn't have anything to do with the crime. (i got this information from this site http://www.botany.org/planttalkingpoints/crime.php#Milne) (I got the image from http://www.cbclearning.ca/media/catalog/product/cache/6/image/800x600/17f82f742ffe127f42dca9de82fb58b1/Z/Z/ZZY-09-07_450__1.jpg) My opinion of Forensic Botany, well it isn't the greatest job in the world because you don't get to use some of the evidence you get from crime scenes if it deals with plants in court.