Distinctive features of S. parksii as compared to other fall-blooming species in the Navasota Flora
Hugh D. Wilson - TAMU Herbarium with photos by  James Manhart, David Reed, and Hugh Wilson (TAMU Biology/Horticulture)
Full set of Spiranthes photos from the Vascular Plant Image Gallery

Botany 301 Students:  If you encounter Fall-blooming Spiranthes and take a sample for your collection, collect only the inflorescence and its stalk by removing at the soil surface.  The plants are perennial with the inflorescences produced from an underground rhizome.  Thus, if you limit your sample to parts of the plant that are above found, the plant will remain intact for flowering next year.


 

Spiranthes lacera var. gracilis:  Usually tall, delicate inflorescences that appear 2-3 weeks prior to those of parksii/cernua.  Easily distinguished by the green coloration on the inside of the lowest petal of its flowers, which are smaller and usually more numerous (per inflorescence) than parksii/cernua.

Leaves - S. parksii/cernua
Leaves - S. lacera var. gracilis
Fall-blooming Spiranthes produce a basal rosette of leaves shortly after flowering.  These persist until late Spring and the plants are not evident until inflorescence emergence in October/November.  Leaves of  parksii/cernua are long, narrow, and often lustrus whereas those of S. lacera var. gracilis are short, wide, and generally dull.  The rosette leaves of parksii and cernua are similar, i.e., the two species cannot be determined on the basis of rosette leave structure.


 
Spiranthes parksii
Spiranthes cernua (typical)
S. parksii flower, side view

Flowers of S. parksii have short lateral petals, i.e., the sepals are longer than the petals and, as a result, the ends of the sepals appear as extensions at the tip of the flower.  Typical cernua types (left, right photo) have flowers with lateral petals and sepals about the same length and the extended sepal tips are not evident.  As compared to typical cernua types, the flowers of parksii tend to extend from the inflorescence stalk at an angle, as opposed to being perpendicular to the stalk.  The parksii perianth (sepals + petals) is not as long as that of typical cernua and tends to be cream colored, as opposed to bright white.  Thus, typical or 'woodland' cernua is a more 'showy' orchid.




Spiranthes cernua - peloric or closed type
The 'closed' type of Spiranthes cernua produces a flower that rarely opens, i.e., the perianth parts (sepals/petals) remain clustered together.  The plants appear to be in the process of early inflorescence development, but inhibition of full anthesis (perianth opening for pollinators) is indicated by the presence of plump, developing ovaries located beneath the perianth.  Plants of this type tend to be delicate when found in shaded, woodland habitats and more robust, often as colonizers, in open fields or roadsides.


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