Sunday, July 4, 2010

The Dichanthelium Series: Dichanthelium lanuginosum

This is the most commonly encountered Dichanthelium in the eastern United States. Correspondingly, it is the most generalist species of Dichanthelium in the eastern United States. It has 26 synonyms that loosely represent its range of morphological and geographical variation. It is often lumped with D. acuminatum. In Michigan, Wisconsin and the Chicago region, it is erroneously referred to as D. implicatum (a travesty that won’t soon be rectified and that largely hinges on the cult of personality).

The sheaths are pubescent with short uniform hairs. The vernal stem leaves (biggest leaves on the stem) are oriented nearly 90 degrees from the stem. The adaxial leaf surfaces can range from glabrous to villose to velutinose; consistency is found at the population level. The spikelets average around 1.6mm long.

Ligule length is the strongest character. Unlike D. acuminatum (to which it is only distantly related), D. lanuginosum has a uniformly long (2.0-4.0mm) ligule. It also lacks the ciliate leaf margins of D. acuminatum which has margins akin to D. laxiflorum (for those in the know).

It disturbs me that the most common Dichanthelium, the weedest Dichanthelium, in the eastern United States is so shamefully misunderstood. This presents a sad dichotomy in that scientists travel the world, infinitely dissect cells and monophylogenically clade molecules in attempt to discover new ways in which organisms manifest themselves from the biotic and abiotic ether of existence, but so easily lump or ignore that which strays from the convenience of preordained knowledge right in their back yard. Such ignored mysteries harbor the bulk of missing knowledge.