Studies in Sidalcea Taxonomy

RichardR. Halse,4535 N.W Big Oak place,No. 3, Corvallis,Oregon 97330 Bruce A. Rottink,' and RichardMishaga, CH2M Hilr,rnc. 2020SW FourthAvenue, Portland, Oreqon g720.1 Studiesin SidalceaTaxonomy Abstract The-objectives of this study were to inyestigate taxonomic relationships among the four species of Sidalcea growing in Oregon,s Willamerte Valley, and among various populations of Sid,alceaneioniona.lhese relaiionships were u..""s..d b'y exa-rning pollen with the scanning electron microscope, and performing principal component analysis(PCAfon gross mo.phologi"uii.uru.". of the plants. Pollen morphology was of limited use in making intra- and inter-specific comparisons. Chro-o.o-e"number was determined for six populations of S. nelsoniana; it was identlcal for all populaiions (n = to). pCA was useful in segregatrng the four Sidalcea species. However, a PCA of 73 specimens of S. neLsoniina revealed no distinct sub-taxa; this i.flrrira'o, is useful in making management decisions for this Category 2 candidate species. Introduction existenceof S. nelsonianain thesetwo different habitats has led to speculationthat there may Sidalcea is comprised of herbaceousannuals and be two separatetaxa. This paper also examinesthis perennials native to western North America hypothesis. (Roush 1931,Hitchcock 1957).The four species The proposed found in the Willamerte Valley of Oregln, S. constructionof a water supply reservoir at Walker nelsoniana Piper (Nelson's checker-mallow),S. Flat in the Coast Range, west of Carlton, would inundate cusickii Piper (Cusick's checker-mallow), S. an area which cur- rently supports a large population campestris Greene (meadow sidalcea). and S. of S. nelsoniana (Glad et al. 1987). Determining airgata Howell (rose checker-mallow), are all the taxonomic status of the S. nelsonianaat perennials that bloom in late spring to mid- Walker Flat would help federal agenciesassess the summer and are characterizedby a gynodioeci- signifi- cance of managing this population. ous breeding system.In a gynodioeciousspecies individual plants are either pistillate (the flowers Materialsand Methods are male-sterile)or hermaphroditic (the flowers are perfect). Often morphological differences, Relationshipsamong the four speciesof Sidalceo, such as overall plant size or flower size (Willson and within S. nelsoniana,were determined by ex- 1983),can be found between these two types of amination of pollen with a scanning eleciron individuals. The existence of these two different microscope (SEM), and principal Jomponent morphological types within a specieshas resulted analysis(PCA) of selectedmorphological char- in frequent misidentification of these species. acteristics. In addition, chromosome counts were Therefore, the primary goal of this study was to made for six S. nelsoniana populations, two from clarify species relationships by examining se- the Coast Range and four from the Willamette lected taxonomic and morphologic characteristics Valley. of these species. Air dried pollen collectedfrom the four speciesof Sidalceawas dispersedon l5 mm diameter The taxonomy of S. nelsoniana, a western coverslips coated with a thin adhesive film Oregon endemic, has been a concern to federal (Mikrostick). Coverslipswere attached to alumi agenciesas it is a candidate speciesfor federal num planchets using conductive silver paint. listing as a Category 2 species(U.S. Fish and After mounting, spqcimenswere coatedwith ap- Wildlife Service 1985).It is found in the '|50 northern proximately A of 60:40 weight p"r..nt CoastRange in both the Nestucca River and the Au/Pd alloy in a Varian VE-10 vacuum evapo- Wilson River drainages, and in the Willamette rator at a vacuumof I x l0-s Torr. Examination Valley from Benton and Linn Counties north to was made using an AMRAY 1000 A SEM, oper- Washington (Halse County and Glad l986). The ated at l0 or 20 kV, at rhe Electron Microscone Facility, Departmenr of Botany and paih- rCurrent Plant Address:l4 Touchstone,Lake 0swego, 0regon 92035 ology, Oregon State University. Images were 154 NorthwestScience, Vol. 63, No. 4, 1989 recorded on Polaroid Type 55 positive/negative TABLE 1. Definition of morphologicalparameters used in 4x5formatfilm. Sidalceaprincipal componentanalyses. For chromosome determination, floral buds Abbreviation Definition Numeric Code from six populations of S. nelsonianawere col- lected in the field and fixed in a modified Car- BASTPU basal stem I = none noy's solution (4 chloroform: 3 ethanol: I glacial pubescence 2 = simple = acetic acid, v/v/v). Acetocarmine squashes of 3 forked or stellate pollen mother cells were obtained by using the PETCOL petal color I = white or pink = technique of Snow (1963). 2 red, lavender or purple The morphological measurements for this ADPETLG adjusted petal millimeters study were obtained from l3l herbarium speci- lcnoth mens of the four species of Sidalcea borrowed ADCATTG adjusted calyx millimeters from the herbaria at Oregon State University, the length University of Oregon, Washington State Univer- CAtCOt calyx color I = green sity, the University of Washington, Willamette 2 = green with some University, and the United States Fish and Wild- purple = life Service,Boise, Idaho. Of thesespecimens 73 J purple were of S. nelsoniana,22 of S. campestris,2l of S. uirgata and l5 of S. cusickii. Specimens were from throughout the species'distribution in the species on the length of the petals and calyces. Willamette Valley. A list of the specimens,and Therefore, for the PCA, the length of the petals their site localities,used in the PCA is available and calyces were adjusted for sex-related flower from the senior author on request. differences. For both petals and calyces,this adjustment was made separatelyfor each species The five morphological parameterslisted in by adding the difference between the mean Table I were measured on all l3l herbarium Iength of the perfect-flowered specimensand the specimens.Only those specimenswhich had all mean length of the pistillate-flowered specimens five morphological parameterswere used in the to each of the pistillate-flowered individuals. PCA. These parameters nere selected for the Following this adjustment, the mean length of PCA becausethey are considered to be impor- the pistillate-flowered individuals was equal to tant traits in the latest monograph of the genus the mean length of the perfect-flowered in- (Hitchcock 1957)and are traits emphasizedin the dividuals. This eliminated segregation of in- latest regional flora (Hitchcock and Cronquist dividuals based solely on the sex of the flower. 1973).Sixteen morphological characterswere ini Data on the five parameters listed in Table I for tially examined (CH2M Hill 1986).Many of these S. nelsoniana, S. airgata, S. cusickii and S. characterswere judged to be so similar among campestris were analyzed by a PCA computer speciesas to be non-discriminatingand were not program (SAS Institute Inc. 1985).The raw data included in the investigation (e.g., calyx pu- from the specimensused in this analysisare sum- bescence,flower density, upper stem pubescence, marized in Table 2. style number). Other characters, while important taxonomically, are usually not found on most her- Following the PCA of the four species,a PCA barium specimens(e.g., root type, fruit traits). was performed on 73 specimens of Sidalcea nelsoniana alone, in order to examine the relation- Examination of the herbarium specimens ship between the specimens found in the Coast revealed that the flowers on the perfect-flowered Range, particularly those from Walker Flat, and plants tended to be larger than the flowers on those of the Willamette Valley. the pistillate-floweredplants. The influence of sex on the parameters used in the PCA was tested Resultsand Dascussion using a factorial analysis of variance (ANOVA) with flower sex and speciesas the factors. The The pollen of all specimensof Sidalcea is typical- number of specimensof each speciesand flower ly malvaceous (Figure l). The grains are 60-70 type are indicated in Table 2. This analysis in- microns in diameter, are conspicuously spiny, dicated a significant effect of flower sex and have a granular surface and are pantoporate. Sidalcea Taxonomy 155 TABLE 2. Means and standard deviations of morphological parameters for Sidalcea species analyzed in the principal com- nonent analvsis. Parameter' Flower Species Sex n BASTPU PETCOL PETLG CALLC CALCOL S. nelsoniana Perfect 4I 2.0+ 0.3 2.0r 0.0 I 1.5+ 2.0 5.5a 0.7 2.0r0.2 Pistillate 32 2.0+0.2 2.0a 0.0 7.1r 1.3 4.7+0.7 2.0+0.2 S. uirgata Perfect ll 3.0r 0.0 2.010.0 19.8r 3.6 8.7+ 1.4 1.7i 0.5 Pistillate l0 2.9r0.3 2.0+ 0.0 lu.6+ r.5 6.3i 1.2 1.8+ 0.4 S. cusickii Perfect 8 2.5t 0.9 1.9+ 0.4 I4.5i 3.5 7.8i2.0 1.9r 0.4 Pistillate 7 3.0t 0.0 2.0r 0.0 9.7+ 1.7 6.9r 0.8 1.8t 0.4 S. campestris Perfect l5 2.1!0.4 l.I r 0.2 17.3,t 4.6 7.5+1.3 1.7r0.5 Pistillate 7 2.0r 0.0 1.0+ 0.0 10.2t0.7 6.1r0.7 1.6+0.5 'See Table I for definitions of parameters. The smooth,sticky surfacematerial coveringat dicates that the magnitude of the effect of flower leastpart of the granularsurface (Figure l-C,E) sex on petal and calyx length varies among is dueto thepresence of pollenkit(Dobson pers. species(Table 2). comm.),which has been reported from other The first two components of the PCA for the speciesof Sid,alcea(Dobson 1988). Although the four speciesof Sidalcea account for 70.6 percent pollenof S. campestrisexhibits some variability of the total variation, and are plotted in Figure in sizeand shapeof the spines,the pollengrains 2. The eigenvectorsfor each component are listed of all the taxa are very similar and do not ap- in Table 3.

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