| Cenchrus echinatus |
| The
spikelets are enclosed in a special covering called a * bur
(or burr) - a term which has been used loosely (esp. in the
temperate) to describe a 'seed-coat' that is armed with spines. In
the case of Cenchrus echinatus, the spines are not only sharp
and rigid, but are armed with minute recurved barbs. These barbs aid
dispersal as they are well-suited to hook onto the fur of passing
animals. As for the adventurous naturalists, they will soon learn that the spines readily draw blood when under-estimated and mishandled ! * the bur is a vegetative organ derived through the evolutionary modification of sterile branchlets fusing together as one membrane. In many other grass species, bristles are formed instead. |
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