Wednesday, January 5, 2011

Red Berries coastal California, winter it is not, coincidence neither

An obvious feature of coastal central California settings at the turn of the new year is the presence of both native and introduced shrubs and trees with fully ripe, red fruits. Red fruit = bird dispersal. At this time of year in coastal central California it is hardly winter for many vascular plants, as temperature is suitable for growth and moisture is no longer limiting. In the Santa Cruz Mountains we have toyon (Heteromeles arbutifolia) as the sole native red berried shrub. Close by one finds madrone (Arbutus menziesii) which in some regions this year are very heavily laden with ripe pendant clusters of fruit. One of the common names of toyon is Christmas berry.

Non-native shrubs, largely Rosaceae, are juxtaposed against the natives: cotoneaster (C. franchetii and C. pannosa) and pyrracantha (P. angustifolia). Often one can see mixed stands of both native and non-native red berried shrubs. One can, and I do, also point to a non-rosaceous, but relatively rarely encountered red fruited shrub, Ilex aquifolium, English holly (Aquifoliaceae), an asterid eudicot contrasts to the others, which are rosids. Coincidence of red fruits? No. Clearly selection for bird dispersal which has produced this syndrome in unrelated lineages.

Interesting, there are known genetic variants of both native and non-native rosaceae with orange rather than red fruit. The photo is such a variant of pyrracantha, perhaps P. fortuneana. A named race of toyon, H. arbutifolia var. cerina (Jepson) E. Murry with yellow fruits is a similar genetic variant. In the case of the pyrracantha in the photo, the variant is orange vs. red

Plant taxonomists are a wishy-washy bunch, as if they do not want to be ever caught with their names in parenthesis, so the yellow variant of toyon is not considered a 'taxon'. Get real folks, it is genetically based, is it not? Ought names be coined to facilitate our use, and ought not those names, when used, be taken to refer to specific genome features? Taxonomists: recognize H. arbutifolia var. cerina please, and get over species denial.

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