Blue-Eyed Grass

Sisyrinchium angustifolium

(Sisyrinchium comes from Greek for “pig-snout,” reportedly because hogs dig the roots, although to my eye the yellow anther cluster resembles a pig snoot.  Angustifolium means narrow-leaved.)

Iridaceae – the Iris Family

Sisyrinchium angustiphyllum by John Bradford

Thanks to rain, no fieldtrip this morning, so I’m turning back the hands of time to the wet meadow my PBSC botany class explored yesterday at Sweetbay Natural Area near Palm Beach Gardens, Florida.  The wet prairie flowers are glorious now, and the fairest of the fair is Blue-Eyed Grass.

S. xerophyllum by JB

Sisyrinchium is a genus with about 80 species, essentially native to the Americas.   With controversial species definitions, we have 3 or 4 species locally, ranging in preferences from sun-cooked scrub sands to soggy meadows.  We’ll concentrate on narrow-leaved blue-eyed grass, Sisyrinchium angustifolium so elegantly in flower now.   Beautiful!   Looks like a tiny Iris to which it is related.   The similar S. nashii has tufts of fibers at the base of the clump.

Sisyrinchium angustifolium ranges all the way from Palm Beach palms to Canadian ice.  Those blue flowers with fancy yellow eyes host mostly bees and certain flies,  not to exclude possible butterflies.    That tidy picture belies a complex floral structure and equally complex evolutionary history.

Toxomerus geminatus Syrphid Fly enjoys Sisyrinchium. Photo contributed by John Lampkin.

The flower has an idiosyncratic construction probably dating back to bird-pollinated ancestry according to the late botanist Verne Grant, famous for interpreting floral features functionally.  The seed-bearing inferior ovary hangs below the flower out of harm’s way relative to big abusive pollinators such as birds.    Even more indicative of avian predecessors, the center of the flower sports a column made of the male stamens fused into a tube around the female style and stigmas.   Dr. Grant interprets such a stamen tube as a bird-beak-shield, as you see in big Hibiscus flowers.   The tube protects the delicate style in the fashion plastic insulation protects a copper wire.

Stamen tube, the column, at center of flower. Style and stigmas are hidden within.

Later…stigmas protruding from column tip.

Later still, stigma bent outward between anthers.

 

At the base of the column is a brush of large yellow hairs, and at the column tip are the bright yellow anthers.  Both features beg attention.   First the hairs.   Their role in attracting pollinators to today’s species is unclear, possibly due to its northern distribution.  In Tropical American Sisyrinchiums  the hairy brush secretes oils to feed tropical bees.   But North America is not a land of oil-collecting bees, and it seems our species has lost the oil.  Despite possessing the hairs normally associated with oil production, tests have shown S. angustifolium surprisingly bereft of oil.  But who knows, maybe the beard still contributes somehow to pollinator satisfaction.    The scentless flowers are another point consistent with bird-pollinated ancestry.

Hairs at column base. Where’s the oil?

To wrap it up, how about those three big yellow pollen-producing anthers topping the column?   When the flower is young they are shedding yellow pollen but no female parts stand encased within the column.   The tip of that hidden style has three slender stigmas (pollen-receiving lobes).   The stigmas eventually push up into the light of day above the anthers, switching the flower’s sex from male to female.  The stigmas bend finally outward between the anthers.