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Vol. 6(3), pp. 9-15The McAllen International Orchid Society JournalMarch 2005

Spiranthes parksii Correll - Navasota Ladies' Tresses

Cliff Pelchat

S. parksii, the "Navasota ladies' tresses" is the only endemic orchid that Texas can claim and it has had an elusive history since its discovery in 1945. It was first described by Donovan Stewart Correll, (Correll 1947). In his 1950 book, Native Orchids of North America North of Mexico, Correll states that it was discovered in Texas in 1945 and that it had no close allies in North American orchid flora. "This species has no close allies in our flora. Its affinity seems to be with several Mexican and Central American species. It apparently occurs in moist habitat, and blooms in October" (Correll 1950). The specimens Correll used to describe the Navasota Ladies' Tresses were collected by Haliburton Braley Parks along the Navasota River (Democratic Bridge) in Brazos County, (Correll 1947). For the next 30 years H. B. Parks was the only person to have seen a live specimen of this plant. Many of the herbarium specimens deposited by H. B. Parks contain short non-specific descriptions for location (e.g. "Democratic Bridge"), which certainly contributed to the difficulty of locating existing populations of S. parksii. With Correll, Carlyle Luer searched for the plants on two different occasions without finding them leading him to speculate on their origin; "The writer has thoroughly searched the type locality, along the Navasota River in eastern Texas, in two different years, once with Dr. Correll, but without success. Within a radius of a few miles, three familiar species of Spiranthes were discovered in flower: S. cernua, S. ovalis, and the robust Texan S. lacera var. gracilis,... It is considered unlikely that a southern relict might survive in the western part of the Coastal Plain and the Eastern Woodland where no other localized endemic species of orchid is known to occur. However, endemic species of other plants are not infrequent. Very possibly Spiranthes parksii represents an aberrant or polyploid form of var. gracilis, or a non-persisting hybrid of var. gracilis and S. cernua." (Luer 1975). Nevertheless S. parksii Correll was listed as endemic to Brazos County, Texas (Correll, 1950; Correll & Johnston, 1970). In 1975 it was listed as an Endangered and Threatened Orchid of the United States (Ayensu 1975), and in 1982 it was listed as federally endangered (MacRoberts & MacRoberts 1997). Throughout the 1980's and 1990's it had a tendency to become newsworthy such as when it stopped the expansion of Texas highway 6 in 1983 (Liggio, 1999), or when it became the focus of a conservation effort in 1990 that involved the Marie Selby Botanical Gardens and the San Antonio Botanical Gardens, when 500 plants were reproduced for planting back into the wild (Houston Chronicle, 1990).

Rediscovery

On October 25, 1978 the Navasota ladies' tresses species was rediscovered in Brazos county by Paul Catling and K. L. McIntosh in a Post Oak woodland northwest of the town of Navasota (Catling and McIntosh 1979). They located 7 plants along the banks of a temporary stream surrounded by scattered oaks (Post Oak, Quercas stellata, and Blackjack Oak, Q. marilandica) along with American Beauty Berry (Callicarpa americana). Another site with 13 plants was also discovered close by in an open oak woodland on the banks of another temporary stream. They reported that S. parksii Correll occurred both on the tops of banks in open sand with a sparse cover of grass and on the sides of banks in the shade of tress and thickets. Since that time it has been documented in Lee, Leon, Freestone, Grimes, Burleson, Madison, Robertson, Fayette, Washington and Jasper counties (Bridges & Orzell, 1989; and Liggio, 1999). The Jasper county site represents a small disjunctive population within the Piney Woods of Angelina County National Forest in East Texas 170 kilometers east of all other known populations. Recent surveys of the Jasper County Black Branch Barrens area of the Angelina National Forest have resulted in finding a few other plants (MacRoberts & MacRoberts, 1997).

Range/Habitat

Fig. 7. Confirmed and likely sites of Spiranthes parksii. Source: C. Pelchat.

With the exception noted above for Jasper County, Spiranthes parksii inhabits the Post Oak Savannah region of East Texas (Fig. 7). The Post Oak Savannah region is located northwest and west of Houston and occupies a space between the Blackland Prairies to the west and the Piney Woods to the east. To the south the Post Oak Savannah tapers out and mixes with the Blackland Prairies habitat. This unique habitat is made up of an area of about 8,500,000 acres of gently rolling hills with elevations from 200 to 800 feet above sea level. It receives about 35 to 45 inches of rainfall annually with the peak rainfall occurring during the months of May or June. Vegetatively it consists of open fields dominated by tall grasses and spots of woodlands populated mostly by Post Oak (Quercas stellata) and Blackjack Oak (Q. marilandica). Soils consist of acid loamy sands in the upland areas to acid loamy sands and clays in the bottomland areas (Correll & Johnston, 1970). The area was extensively cultivated for grains, vegetables and fruit trees up through the 1940's (Wilson, unpublished), and this cultivation may explain the rarity of S. parksii and the disjunctive nature of some of the populations.

Within this range Spiranthes parksii is found mostly along drainage areas that represent naturally disturbed areas through the Post Oak woodlands leading to the Navasota river and is rarely if ever found in unnaturally disturbed areas such as roadsides, power-line right of ways or open fields (Wilson, unpublished). When I first began searching for this plant I looked in the open grassy areas near woods and along drainages areas [outside of woods] as described by others and as noted on herbarium sheets, e.g. Texas International Speedway. Though I found some plants, mostly at the beginning of drainage areas from the grassy fields leading into woodlands and adjacent to the edge of woods along hiking trails the most plants were found within the woods on the banks of the natural drainage ditches. This observation confirms that S. parksii does not typically inhabit open areas or areas disturbed by man. Today S. parksii is well documented growing in the Navasota region and one especially good and accessible (because it is not private property) location is Lick Creek Park located in College Station. I have observed it growing in this park along the banks of drainage streams and at the mouth of these drainage areas leading from the open grassy areas of the Post Oak Savannah. I have also observed it growing on the margins of the wooded forest near drainage ditches where hiking trails have been formed. This habitat lies in close proximity to Texas A & M University and Dr. Hugh Wilson, from the University, undertook a detailed study of S. parksii. Unfortunately this study was brought to an abrupt halt by the expansion of a recreational bike path.

Morphology

The genus Spiranthes is highly variable from the morphological point of view and, at times, it is difficult to differentiate between species in the field. The problem of field identification is compounded for the species S. parksii because it blooms at the same time and in the same range as two other species, S. cernua (L.) L.C. Richard and S. lacera Raf. var. gracilis (Bigel.) Luer, and is found in similar habitat as S. cernua mixed in with blooming populations. However, once one establishes a pattern of identification there is no mistaking S. parksii for either S. cernua or S. lacera var. gracilis, though there are some plants that seem to be intermediate between S. parksii and S. cernua, and these are not easily resolved in the field. While photographing these plants with a 10mm. macro lens, many of the characters described by Correll (1947, 1950) are apparent. The line drawing by G. Dillon that accompanies Correll's description is extremely accurate, and looks as though it was drawn from a live specimen rather than from a herbarium sheet.

Fig. 8. S. parksii inflorescence. Photo: C. Pelchat.

Fig. 9. Springtime growth of Spiranthes parksii. Photo: C. Pelchat.

The plants I have observed are from 21 cm. to 25 cm. tall with the flowers taking up the top 7-8 cm. of the spike (Fig. 8). They are in 4 ranked coils of 14 to 30 flowers spiraling counterclockwise looking down on the top of the plant. The plants tend to have the flowers concentrated more at the top of the rachis, generally twisting in a counterclockwise direction forming 4 ranks, giving the rachis a symmetrical appearance. In contrast S. lacera var. gracilis tends to have a single rank forming a long spiral to the top for most of the length of the rachis. There are no leaves present at anthesis, but I have observed the leaves of plants in the springtime and they form basal rosettes of 2 to 3 lanceolate-elliptic leaves (Fig. 9). It should be noted that I find the number, size and dimensions of leaves for Spiranthes sp. to be quite variable depending on the time of year observed, the amount of moisture present, and apparently the amount of nutrients in the soil. Plants of S. vernalis grown in pots and fed high nitrogen fertilizer have produced over 8 large grass like leaves along with one large bract like leaf on the spike that have sustained through anthesis compared to the 4 to 5 often observed in the field. These observations suggest that identification of S. parksii based on vegetative characteristics of the rosettes is highly unlikely unless the plants were specifically marked while in bloom.

The flowers and most of the rachis are covered in a fine pubescence the apex of which is tipped with a ball or club. The same pubescence is found on S. cernua but S. lacera var. gracilis is essentially glabrous. The characteristically obovate petals (Correll 1947), are also easily seen in the field through the lens of the camera or with a 10x loupe. The lip is presented in such away that the apex has a cleft and the center leading inward to the column is padded on each side and creamy yellow in color, (this coloring is also described by Catling & McIntosh 1979). The margins of the lip are ragged and tooth like or in botanical terms dentate compared to the crenulate (scalloped or round toothed) and undulate (wavy) appearance of S. cernua. Small pubescent hairs can be observed in the throat of the corolla formed by the lip, dorsal sepal and petals. The distinctive oval shape of the petals (Correll 1947) can be seen, in the field, under close observation with a loupe or through the lens of a camera. The floral bract is white tipped which is often referred to as a single identifying characteristic of this orchid, but (in this author's experience) cannot in itself be used as a single characteristic for identification because S. cernua can also show a tendency for whitening of the floral bracts. Overall the flower shape of S. parksii is quite distinctive in that it appears to be short and fat. When viewed from the side, the flower from the ovary to the tip of the dorsal sepal forms an arch giving the flower a humped shape in relation to its length and width and extends horizontally from the rachis instead of drooping or nodding as in the case of S. cernua. The dorsal sepal extends just beyond the petals, curls upward at the apex, and has a cleft at the apex. The lateral sepals hug the corolla tightly and look like 2 upturned horns following the lines of the upturned apex of the dorsal sepal and extending a little beyond it. The flower coloring is white with variations from creamy yellow to white in the center of the lip and yellow to light green coloring running through the petals from the base to the midpoint.

Fig. 10. Spiranthes cernua.

Fig. 11. S. parksii, "Cleistapogamic" form. Photo: C. Pelchat.

Fig. 12. Apomixic form of Spiranthes parksii. Photo: C. Pelchat.

In the same location, and, as mentioned above, blooming simultaneously with S. parksii is S. cernua, (Fig. 10). These plants include examples of the sexual and asexual apomictic types along with peloric forms as well as the "Cleistapogamic" characteristic referred to by C. Sheviak, (1982) (Fig. 11). I have also observed examples of S. parksii that appear to be apomixic, and exhibit some peloria, (Fig. 12). These plants have monstrous looking tightly closed flowers with the lip barely protruding pointing straight up parallel with the axis of the stem. On some of the flowers the lateral sepals are at an angle away from the corolla and many of the unopened flowers below, at the bottom of the spike, are already withering while the ovaries are swelling. Another most unusual characteristic was the almost completely white floral bracts. Close examination of these revealed fine green striping running lengthwise to the apex, but they were mostly white. I have observed the same white coloring in the ovaries of peloric forms of S. cernua. I have also observed plants that seem to be intermediate between S. cernua and S. parksii in that they have the general appearance of S. parksii with regards to general flower shape, presentation of the lateral sepals, and white tipped floral bracts. However the lip margin is much more undulate and the lateral sepals are not as closely pressed to the corolla. C. Sheviak noted that S. parksii is linked to the S. cernua complex "by its reproductive mode and some morphological characteristics and indeed is likely related" (Sheviak 1982). I believe that further, more detailed, studies of S. parksii are required to understand its standing within the S. cernua complex and will lead to a clearer understanding of the origin of this species.

Conservation

Earlier in this article mention was made of Lick Creek Park and the bike trails that destroyed the on-going study that was being conducted by Hugh Wilson from the Texas A & M University. In this case the community of College Station wanted recreational mountain bike trails and the best habitat for this type of recreation happens to be prime habitat for S. parksii. Score: humans 1 orchids 0. Repeated attempts by Dr. Wilson to have the area set aside as a preservation area fell on deaf ears, both at the community level and the national level, e.g. the Federal Government and the Nature Conservancy. Even Texas highway 6 was allowed to proceed through prime S. parksii habitat once a so-called mitigation plan, involving a preservation area now referred to as a weed lot was built (Wilson unpublished). New score: humans 2 orchids 0! The most disturbing example of habitat destruction for S. parksii, however, is the clear cutting of trees in documented S. parksii habitat (remember it is essentially a woodland orchid) has been for the purpose of building the giant Texas A&M bonfire in the name of tradition and school spirit. Final score: humans 3 orchids 0! They (the orchids) are out!

In 1994 Hugh Wilson made repeated attempts to save this habitat from destruction, appealing to both the Texas A&M University administration, and to the Director, Office of Endangered Species for the U.S. Fish and Wildlife Services. Of course all of the habitat destruction is well within the boundaries of the law and perfectly legal, but one has to question the ethical ramifications and hypocrisy of this situation. Ironically the only true protection of S. parksii is being afforded by the Texas Municipal Power Authority (TMPA), as a result of strip-mining operations on leased land. This protection will also disappear as the mining operations wind down and the land leases expire removing them from the stewardship of the TMPA.

Summary

Fig. 13. Close-up of S. parksii flowers. Photo: C. Pelchat.

S. parksii Correll (Fig. 13) is an interesting and unusual orchid. It is interesting to students, scientists, and wildflower enthusiasts because it has a limited range and therefore can teach us much about the conservation of orchid species as we continue to study its habitats. The general observations of the Lick Creek Park populations show there are similarities between S. parksii and S. cernua, and indicate further, that more detailed studies will result in a better understanding of these relationships. Spiranthes parksii is unusual in its very rarity as a native Texas wildflower. Whether any given wildflower, bird, or animal is of intrinsic value to the state and its citizens remains something of an ethical question: one having to do with how citizens view their quality of life within the social structure. It is hoped that a greater awareness of this orchid and others like it will lead to better conservation efforts by individuals and ensure all the natural wonders presently around us are available to future generations.

References

Ayenus, E. S. 1975. Endangered and Threatened Orchids of the United States. Amer. Orch. Soc. Bull. 44(5): 384-394.

Catling, P. M., and K. L. McIntosh. 1979. SIDA 8(2): 188-193.

Correll, D. S. 1947. A new Spiranthes from Texas Amer. Orch. Soc. Bull. 16: 400.

_______. 1950 (reprinted 1978). Native Orchids of North America North of Mexico. Stanford, California: Stanford University Press. 399pp.

_______., and Marshall C. Johnston. 1970. Manual of The Vascular Plants of Texas. Renner, Texas: The Texas Research Foundation. 1881pp.

Bridges, E. L. & S. L. Orzell 1989. Additions and noteworthy vascular plant collections from Texas and Louisiana, with historical, ecological and geographical notes. Phytologia 66: 12-69.

Houston Chronicle 1990, Kathy Huber. Lab Gardeners Try To Thwart Orchid Pirates. Houston Chronicle, Saturday 2/10/1990, P.1, 2 Start edition.

Liggio, J. and Ann Orto Liggio. 1999. Wild Orchids of Texas. University of Texas Press.

Luer, C. A. 1975. The Native Orchids of The United States and Canada excluding Florida. New York: The New York Botanical Garden. 361pp.

Evans, Robert E. and MacRoberts, Michael H. and MacRoberts, Barbara R. 1997. Notes On Spiranthes parksii Correll (Orchidaceae) Deep In East Texas. Phytologia 83(3): 133-137 (September)

Sheviak, C. J. 1982. Biosystematic Study of the Spiranthes cernua Complex. New York State Museum Bulletin No. 448.

Wilson, H. D. unpublished. Spiranthes parksii--Endangered Orchid of the Texas Post Oak Savannah, Texas A. & M. Website.

Copyright © 2005 Cliff Pelchat