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Vol. 6(7), pp. 8-11The McAllen International Orchid Society JournalJuly 2005

A Pictorial Monograph of Three Spiranthes Species and Their Hybrids

Cliff Pelchat

According to Luer (1972), two spring blooming Spiranthes, S. praecox (Walter) S. Watson and S. vernalis Engelmann & Gray, have similar blooming times and ranges. As will be seen in the following photographs there appears to be hybridization between S. praecox and S. vernalis. Additionally, a third species that can be grouped with these, was recently described (Brown, 2001) as Spiranthes sylvatica P. M. Brown. S. sylvatica is very similar to S. praecox and distinguishing between the two species requires examination of actual specimens along with field notes as to habitat, e.g. in shaded woods versus alongside of roads, etc. A fourth, late-summer-early-fall blooming species, Spiranthes lacera (Rafinesque) Rafinesque var gracilis (Bigelow) Luer, is also found in similar habitats as S. vernalis and S. sylvatica, but it differs in both blooming period and specific morphology.

At the outset, the author would like to note that the genus Spiranthes is complex and many times it is difficult to distinguish between species in the field and it is especially difficult to make a determination as to a specific species based only a photograph or a few photographs because of many factors, including film color temperatures, camera angles, lens qualities, focal lengths used, and other considerations. The information presented here, although photographic, is also based on clinical observations and personal field notes except where noted.

Spiranthes praecox (Walter) S. Watson

Spiranthes praecox is an early spring bloomer first observed in February on the east coast of Florida, and this same species has been observed by this worker in bloom in East Texas as late as June. The common form has a lip with green veins, lateral sepals that are appressed to the corolla, club-tipped pubescence and the tendency to have browning at the edge of the sepals and petals, presumably caused by the visiting pollinators. Plants can reach heights of more than 60 cm. and their 5 or 6 leaves may be as long as 25 cm. (Luer, 1975, p 104). This species also appears to hybridize with S. vernalis, and the various forms are described below. They also have 2 or more rows of flowers in the spiral. Luer (1975) also states,

"they frequent damp meadows, sparse woods and road banks

where frequent mowing discourages competing vegetation."

Fig. 1. S. praecox; Angelina Natl. Forest, in sandy ditches and along pine forest roads-Texas; June, 1999

Fig. 2. S. praecox; Angelina Natl. Forest, in sandy ditches and along pine forest roads-Texas; June, 1999

Fig. 3. S. praecox; Angelina Natl. Forest, in sandy ditches and along pine forest roads-Texas; June, 1999

Fig. 4. S. ×meridionalis P. M. Brown (hybd: S. praecox × S. vernalis (ref: Brown, 2004); Six Mile Creek housing dvlpmt Melbourne, Florida, 1995.

Fig. 5. S. ×meridionalis P. M. Brown (hybd: S. praecox × S. vernalis (ref: Brown, 2004); Six Mile Creek housing dvlpmt Melbourne, Florida, 1995.

Fig. 6. S. praecox alba form (pos. hybrid with S. vernalis); Six Mile Creek housing dvlpmt Melbourne, Florida, 1995.

Fig. 7. S. ×meridionalis P. M. Brown (S. praecox × S. vernalis) ref.: Brown, 2004. p. 209; Six Mile Creek housing development; Melbourne, Florida, 1995.

The plants depicted in this group [(Fig. 1) (Fig. 2) (Fig. 3) (Fig. 4) (Fig. 5) (Fig. 6) (Fig. 7)] were observed on road banks along the edge of sparse woods in the Angelina National Forest, Texas; in damp meadows in Six Mile Creek Florida; and along the edge of Slash Pine (Pinus elliottii Engelmann) forests in Six Mile Creek Florida.

Spiranthes vernalis Englemann & Gray

Fig. 8. S. vernalis (ref. Luer, 1975, p. 103); Texas, roadside, 1999

Fig. 9. S. vernalis (ref. Luer, 1975, p. 103); Six Mile Creek housing dvlpmt Melbourne, Florida, 1995.

Fig. 10. S. vernalis (ref. Luer, 1975, p. 103); Six Mile Creek housing dvlpmt Melbourne, Florida, 1995.

Fig. 11. S. vernalis, green form, probably hybridized with S. praecox; Six Mile Creek housing development in Melbourne, Florida, 1995. Note: all the orchids that were in this development are now gone because of new construction since the time these pictures were taken. These hybridizations could have been a local occurrence, and this worker has not observed them in anywhere else. Note the angles and positions of the lateral sepals in this figure. They are very much like S. vernalis, while the labellum resembles that of S. praecox.

Spiranthes vernalis [(Fig. 8) (Fig. 9) (Fig. 10) (Fig. 11)] is also an early spring bloomer seen as early as February on the east coast of Florida and around March in Texas. It can be found in Oklahoma as late as the end of June and early July. I have yet to observe any hybridization with S. praecox in Texas or Oklahoma and also have not yet seen them growing together in habitat. This species also has club-tipped pubescence. The lateral sepals do not adhere to the corolla, but jut out at an angle of about 40 degrees. Also, the lateral sepals have the tendency to be "rolled" into a tube shape. Leaves are usually not present in the field, but this is a plastic characteristic since if you cultivate them with plenty of fertilizer in the garden the leaves will persist during anthesis and will also become less grass-like. It also exhibits some interesting variation in Florida presumably from crossing with S. praecox. There is a creamy yellow coloring on the labellum. They tend to have a single row of flowers in the spiral.

Spiranthes lacera (Rafinesque) Rafinesque var. gracilis (Bigelow) Luer

Fig. 12. S. lacera var. gracilis. Roadside, College Station, Texas 2001.

Fig. 13. S. lacera var. gracilis. Roadside, College Station, Texas 2001.

Fig. 14. S. lacera var. gracilis. Roadside, College Station, Texas 2001.

Spiranthes lacera var. gracilis [(Fig. 12) (Fig. 13) (Fig. 14)] blooms in the late summer early fall in the southern United States and this worker has only observed it in Texas. It differs from both S. praecox and S. vernalis in that it is mostly glabrous with only an occasional pubescence. It also has a green coloring on the lip Brown, 2004 p. 200). The green coloring is persistent throughout the lower portion of the lip and can be seen from the underside of the flower. The flowers tend to grow in single ranks and the leaves are sometimes present at anthesis, but can also be fugacious. I have observed that the presence of leaves is a plastic characteristic. This means that the plant may shed the leaves during anthesis because of environmental factors, e.g. drought stress, low nitrogen, etc. Therefore the presence or lack of leaves should be used cautiously for identification. This species is better identified by the single ranked tightly grouped spiral and the green throat of the labellum.

References

Brown, P. M., 2001. Recent Taxonomic and Distributional Notes From Florida 11: Spiranthes sylvatica P.M. Brown, a New Species of Ladies' Tresses From the Southeastern United States. North American Native Orchid Journal 7(3): 193-205, pl 1. (desc. p. 194).

________. 2004. Wild Orchids of the Southeatern United States, North of Peninsular Florida. Gainsville, Florida: The University Press of Florida. 394pp.

Luer, C. A. 1972. The Native Orchids of Florida. New York: The New York Botanical Garden 1972. 293pp.

________. 1975. The Native Orchids Of The United States And Canada excluding Florida. New York: The New York Botanical Garden. 361pp.

Copyright © 2005 Cliff Pelchat