Ganja, the guaza of the London brokers, consists of the flowering and fruiting heads of the female plant.
These coloured spots are due to the presence of a sorus or layer of countless numbers of minute brown spores, the uredospores of the summer fruiting form.
The developing seed thus encloses fungal hyphae, which remain dormant within the seed and in spring develop symbiotically with the growth of the wheat plant, doing no apparent injury until the time of fruiting is reached, when the fungus takes complete possession and fills the new seed with a mass of darkcoloured spores.
Spikelets oneto indefinite-flowered; in the one-flowered the rachilla frequently produced beyond the flower; rachilla generally jointed above the empty glumes, which remain after the fruiting glumes have fallen.
The flower-stalk becomes recurved in the fruiting stage, and the fruit bears a number of hooks which enable it to cling to rough objects, such as the coat of an animal, thus ensuring distribution of the seed.