CASTANEA 80(4): 262–272. DECEMBER Copyright 2015 Southern Appalachian Botanical Society

A New Hybrid of Asimina (Annonaceae) Based on Morphological and Ecological Data

Charles N. Horn Biology Program, Newberry College, 2100 College Street, Newberry, South Carolina 29108

ABSTRACT Two species of the genus Asimina (Annonaceae), A. triloba and A. parviflora, are well known to occur in South Carolina. Recent work investigating variation in leaf size, flower morphology, and habitat of Asimina in the state shows that a hybrid between the two species exists. The differences in the three taxa are best related to growth form, peduncle length, and outer petal length and width. This new hybrid, Asimina 3 piedmontana, is hereby described and distinguished from both parents. Key words: Asimina, paw paw, hybrid, parviflora, triloba, piedmontana

INTRODUCTION The genus Asimina obovate to oblanceolate, 15–30 cm long; apex (paw paw), of the Annonaceae, was circum- acute to acuminate; base more or less gradually scribed by Kral (1997) to include eight species in attenuate to the short (0.5–1 cm) petiole.’’ Field subtropical and temperate North America. Since measurements of plants in South Carolina agree then, two species have been described, A. with that description, except that leaves were spatulata (Kral) D B. Ward (Ward 2001) and A. observed with lengths up to 45 cm. This species manasota DeLaney (DeLaney 2010), making a can also be recognized by the presence of floral total of 10 known species. Most species are peduncles over 1 cm at anthesis and flowers 2–5 restricted to Florida and Georgia; however, two cm in diameter (Kral 1997). The solitary flowers species are known over a large portion of include sepals 8–12 mm long and outer petals eastern North America, A. triloba (L.) Dunal 15–25 mm long (Kral 1960). and A. parviflora (Michx.) Dunal. Both of these Asimina parviflora (dwarf paw paw) has species are found in a variety of rich woodland been described by Kral (1997) as a miniature sites associated with stream and river valleys. version of the common paw paw with plants up Based on personal observation in the piedmont to 6 m tall; however, plants over 3 m tall are of South Carolina, A. triloba is commonly restricted to the karst country of Florida. Individuals grow on woodland slopes or ridges restricted to river flood plains and stream above streams and rivers where clonal growth bottoms, whereas A. parviflora is more com- has not been personally observed. Asimina monly found on well-drained slopes adjacent to parviflora leaves are ‘‘oblong-obovate to oblan- the bottoms. ceolate, 6–15 (20) cm long; apex acute to Asimina triloba (common paw paw) grows as acuminate; base more or less gradually attenuate a shrub or tree and can reach a height of 14 m to the short (0.5–1 cm) petiole’’ (Kral 1960, p. (Kral 1997). Plants commonly grow clonally in 244). Measurements have revealed leaves up to populations that can cover several hectares of 27 cm long. Plants can be distinguished, as stream or river floodplains. However, Pomper et stated by Kral (1997), by a peduncle less than 1 al. (2009) demonstrated that a local population cm at anthesis and flowers 1.0–1.7 cm in of stems was not always genetically uniform. In diameter. The flowers include sepals that are his landmark revision of the genus, Kral (1960, p. 4–7 mm long and outer petals 10–13 mm long 242) described A. triloba leaves as ‘‘oblong- (Kral 1960). Received June 16, 2015; Accepted December 30, 2015. Geographically, A. triloba populations have DOI: 10.2179/15-067 been recorded from southern Ontario (Canada) 262 2015 HORN: A NEW HYBRID OF ASIMINA 263 to Georgia and west to eastern Nebraska and petals were found to be clearly narrower than eastern Texas (Kral 1997). Asimina parviflora those of A. triloba. Most striking was that the has a more southern distribution, occurring from outer petals were rolled outwards laterally along southern Virginia to northern Florida and west to their length on the hybrid (Figure 1c, 1d). This eastern Texas. The area of distributional overlap was in comparison to outer petals with the between the two species generally occurs within apical tip curved outward on both A. parviflora the piedmont of North Carolina and westward (Figure 1a, 1b) and A. triloba (Figure 1e, 1f). through South Carolina, Georgia, and Alabama. Vegetatively, the hybrid populations also have a Further overlap occurs within the coastal plain different growth form. The hybrids were ob- of Mississippi and Louisiana (Kral 1997). served to have a clonal growth pattern, with Previous work on the reproductive biology of most stems arching over and being no more than Asimina parviflora (Norman et al. 1992) and A. 1.5 m high. This clonal pattern is like that seen triloba (Willson and Schemske 1980) revealed with A. triloba populations. that both species are protogynous with an Observations of herbarium specimens at the overlap of at least one day between stigma University of South Carolina (USCH) revealed receptivity and pollen production. Norman et al. many specimens without flowers or fruits, (1992) then postulated that, at least for A. leading to question whether leaf features could parviflora, pollination and fruit production be used to separate the two species from the could either be the result of self-compatibility putative hybrid on a consistent basis. Further or out-crossing. Despite the two potential study was needed to clarify the status of the mechanisms of pollination, fruit set is typically hybrid and to determine specific morphological less than 10% in nature for both species (Willson and ecological features associated with interme- and Schemske 1980, Norman et al. 1992). diate plants. Thus, the purpose of this investiga- During the growing season of 2006, unusually tion was to determine if vegetative and flowering short-stemmed clonal populations of Asimina, characters would allow for taxonomic separa- typically no more than 2 m tall, were noticed by tion of the three taxa. Kate Goodrich, at that time a graduate student at MATERIALS AND METHODS Vegeta- the University of South Carolina. Further field tive and flowering material was observed and work by the author revealed additional popula- collected during the growing seasons of 2007–10 tions in the piedmont of South Carolina that fit within the piedmont of South Carolina. At least the above morphological description. It was three populations of each taxon were sampled suggested that the populations might represent for leaf and floral material. Voucher specimens hybrid material between the two well-known of both vegetative and flowering plants were species of the region. A review of literature collected and deposited in the herbarium at revealed that hybridization in the genus Asimina Newberry College (NBYC) and are listed in the is common, especially among the species of Appendix. Because plants flower before leaves Florida (Zimmerman 1941, Kral 1960, DeLaney are fully developed, multiple voucher specimens 2010). Kral (1960), in his treatment of the genus, were collected in most cases. noted that hybridization between Asimina tri- Initial identification and placement of popula- loba and A. parviflora is likely, noting herbarium tions into taxa during field trips was based on a specimens with intermediate flower sizes. He combination of two features, habitat and flower cited a collection from Brunswick County, North morphology. Small plants (about 1 m tall) on Carolina as an example. Later, Kral (1997, p. 16) upper slopes that did not appear clonal and had stated that ‘‘putative hybrids between the two flowers with apically excurved petals less than have been observed in northern Alabama.’’ The 13 mm long were considered A. parviflora. potential hybrid nature of the populations in Clonal populations with individuals over 3 m South Carolina, especially at Lynch’s Woods tall growing on floodplains, and having bell- Park (Newberry County) was recognized by shaped flowers with apically excurved petals Horn (2008). more than 15 mm long were considered A. Field work in April of 2007 and 2008 revealed triloba. Putative hybrid individuals (hereafter putative hybrid populations with distinctly inter- called hybrid) were identified from low-growing mediate-sized flowers. Especially noted were the (less than 2 m) clonal populations having petals intermediate length of sepals and petals. The that projected at right angles from the floral axis. 264 CASTANEA VOL.80

Figure 1. Photographs of Asimina species. Hand of author present for scale. (a–b) Asimina parviflora; both photographed at Lynch’s Woods, Newberry County, South Carolina. (c–d) Asimina 3 piedmontana; (c) photographed at Johnson Creek (Union County, South Carolina), (d) photographed at Broad River (Union County, South Carolina). (e–f) Asimina triloba; (e) photographed at Lynch’s Woods, (f) photographed at Pagett’s Creek (Union County, South Carolina).

Leaf measurements were made on plants in used, and on each stem the largest 2–3 leaves the field during June 2009. At each population were measured after realizing that the first- site, 50 leaves were measured for total leaf produced leaves each year are typically smaller length, leaf length to the widest point, and leaf and the terminal leaves were the last produced width. Only branches with multiple leaves were and potentially still developing. Damaged leaves 2015 HORN: A NEW HYBRID OF ASIMINA 265 were not measured if any of the three measure- length population averages ranged from 29.6– ments was compromised. 33.0 cm, length to the widest point ranged from Floral material was collected during April 16.0–20.8 cm, and width ranged from 9.7–12.9 cm 2008 and field preserved in 90% ethanol for later (Figure 3a, 3b, 3c). Populations of hybrids measurement in the laboratory. Only mature, generally had intermediate leaf size. Leaf length burgundy-colored open flowers were collected. population averages ranged from 19.6–27.5 cm, Unfortunately, some populations did not have 30 length to the widest point ranged from 11.3–18.4 mature flowers due to a small number of mature cm, and width ranged from 7.2–10.4 cm (Figure flowers present at the time of visit. The 3a, 3b, 3c). parameters of peduncle length, sepal length Even though population averages allowed for and width, and petal length and width were separation of most populations, individual leaf measured. measurements clearly overlapped among the A Principal Components Analysis (PCA, using three taxa (Figure 3a, 3b, 3c). Populations placed NTSYSpc; Rohlf 2009) was completed to deter- in rank order by average leaf length generally mine if the leaf and flower measurements reflected species; however, overlap was present indicated above could be used to separate the between hybrid and A. triloba with the hybrid H1 three taxa. Data from population averages were (average ¼ 27.5 cm) and A. triloba T1 (average ¼ used in this analysis. Only populations for which 25.3 cm) being out of order (Figure 3a). Further, both leaf and flower measurements could be gathered were used: three of A. parviflora, five no significant difference was detected between of the putative hybrid, and four of A. triloba. A. parviflora P3 (average ¼ 19.6 cm) and hybrid A one-way ANOVA was used with each of the H2 (average ¼ 19.6 cm) (q ¼ 0.03, qcrit ¼ 2.77). eight morphological features to determine if Otherwise, differences among A. parviflora, significant differences existed among popula- hybrid populations, and A. triloba were present. tions. A probability a value of 0.05 was used to Length to widest point showed a similar overlap confirm significant differences. If a significant (Figure 3b). First, it was observed that hybrid H2 difference was revealed from the ANOVA, a (average ¼ 11.3 cm) was less than A. parviflora Newman-Keuls multiple range test was used to P3 (average ¼ 12.3 mm). Also, A. triloba T1 determine differences among ranked popula- (average ¼ 16.0 cm) was less than hybrid H1 tions, also using a critical value of a value of (average ¼ 16.4 cm). Leaf width generated the 0.05. greatest overlap among taxa. The hybrid popu- lation averages varied greatly and clearly over- RESULTS lapped both A. parviflora and A. triloba (Figure Principle Components Analysis 3c). Hybrid H2 (average ¼ 7.2 cm) was not The PCA clearly showed a separation of the significantly different from the smallest A. three taxa in the first dimension. Within the first parviflora (P1, average ¼ 6.9 cm) (q ¼ 2.11, qcrit dimension (which explained 73% of the overall ¼ 3.31). At the other extreme, hybrid H1 (average variation), petal width (coefficient ¼ 0.984), leaf ¼ 10.4 cm) was not statistically different from length (0.979), and leaf width to widest point two A. triloba populations, T5 (average ¼ 10.2 (0.977), were of greatest value. In the second mm) (q ¼ 1.69, q ¼ 2.77) and T3 (average ¼ 10.4 dimension (which explained 4% of the variation) crit cm) (q ¼ 0.21, q ¼ 2.77). was most separated by leaf width (0.448), crit If the hybrid populations were removed from peduncle length (0.231), and petal length the analysis, A. triloba and A. parviflora can be (0.211) had the highest coefficient values (Figure easily separated, most easily using leaf length. 2). The largest A. parviflora length was P3 (average Vegetative Morphology ¼ 19.6 cm) and the smallest A. triloba population Populations of A. parviflora mostly had the was T1 (average ¼ 25.3 cm) (q ¼ 16.89, qcrit ¼ smallest leaves of the three taxa. Leaf length 3.86). Leaf width had the least noticeable population averages ranged from 16.0–19.6 cm, differences between species, with the largest A. length to the widest point ranged from 9.4–12.3 parviflora (P3, average ¼ 9.0 cm) being similar cm, and width ranged from 6.9–9.0 cm (Figure to the smallest A. triloba (T1, average ¼ 9.7 cm), 3a, 3b, 3c). Populations of A. triloba commonly even though the two populations were statisti- had the largest leaves of the three taxa. Leaf cally different (q ¼ 4.86, qcrit ¼ 3.31). 266 CASTANEA VOL.80

Figure 2. Principal Components Analysis graph showing dimensions 1 and 2. Prefix letters are as follows P ¼ Asimina parviflora,H¼ Asimina 3 piedmontana, and T ¼ Asimina triloba.

Floral Morphology Graphical observation of the floral data Population averages for peduncle length varied revealed several important size gaps among the in the range of 3.9–15.2 mm (Figure 3d). No taxa. For peduncle length (Figure 3d), A. overlap of the populations among the three taxa parviflora was distinctly shorter than the other was detected with a size sequence of A. two taxa. The largest A. parviflora (P3, average parviflora < hybrid < A. triloba. Sepal length ¼ 4.9 mm), was much smaller that the smallest population averages ranged from 3.7–12.0 mm hybrid (H5, average ¼ 8.3 mm). A similar gap was (Figure 3e). Like the peduncle length, there was seen for petal length (Figure 3g), with the largest no overlap among the taxa and the order of taxa A. parviflora (P3, average ¼ 7.1 mm) being distinctly smaller that the smallest hybrid (H6, was A. parviflora < hybrid < A. triloba. For average 13.1 mm). The third clear gap was for sepal width the population averages ranged from ¼ petal width (Figure 3h), with A. triloba being 3.5–9.0 mm (Figure 3f). Some overlap among much larger than any population of the hybrid, population averages was detected with no with the smallest A. triloba (T2, average ¼ 19.9 significant difference between hybrid H3 (aver- mm) being distinctly larger than the largest age ¼ 6.8 mm) and A. triflora T7 (average ¼ 6.9 hybrid (H3, average ¼ 11.7 mm). mm) (q ¼ 0.80, qcrit ¼ 2.77). Petal length averages ranged from 4.9–22.0 mm (Figure 3g). There was DISCUSSION Overall, population averages no overlap among taxa except for no significant for the measured leaf size parameters do not difference between hybrid H2 (average ¼ 16.3 allow for distinction among the three taxa of mm) and A. triloba T7 (average ¼ 16.9 mm) (q ¼ Asimina. This makes separation of vegetative 2.18, qcrit ¼ 2.77). For petal width the averages populations in the field difficult. Further, popu- ranged from 5.1–22.2 mm (Figure 3h). No lations do vary, especially in A. triloba. Thus, overlap in population averages was detected when looking at only a few leaves, such as on a among taxa and the size sequence was A. herbarium specimen, classification is a chal- parviflora < hybrid < A. triloba. lenge. 2015 HORN: A NEW HYBRID OF ASIMINA 267

Figure 3. Population parameter measurements. Measured parameters are (a) leaf length, (b) leaf length to widest point, (c) leaf width, (d) peduncle length, (e) sepal length, (f) sepal width, (g) petal length, and (h) petal width. Populations are listed in order (left to right) with increasing average with the vertical bar representing minimum to maximum values. Population abbreviations are explained in the Appendix. 268 CASTANEA VOL.80

Figure 3. Continued. 2015 HORN: A NEW HYBRID OF ASIMINA 269

Figure 3. Continued.

The floral features of peduncle length, petal flora populations are on slopes or upland sites, length, and petal width, are clearly the best stems are typically shorter than 2 m tall, and are flower parameters to help separate the three rarely in clusters of more than five stems. taxa. For each of these three parameters, no Asimina triloba populations are commonly overlap was observed in population averages. restricted to floodplains, have tree-like features Specifically, peduncle length (Figure 3d) and (typically being taller than 3 m), and are petal length (Figure 3g) are best to uniquely distinctly clonal in growth. Hybrid populations identify A. parviflora, whereas peduncle length can be recognized by being located near flood- (Figure 3d) and petal width (Figure 3h) are best plains or on lower slopes, growing no more the 3 to uniquely identify A. triloba.Thesethree m tall and forming clones. morphological features will best allow for In the field, young A. triloba and mature unique identification of the hybrid. Hybrid hybrid populations can sometimes be hard to tell populations have less variation in these charac- apart. Some populations were observed as small ters, so a single flower, as might be found on a clumps of plants (less than 50 stems) with short herbarium specimen, could be used to separate stems (1–2 m tall) that appeared clonal and had the taxa. moderate-sized leaves that could be classified as In the field, habitat features aid in identifying either hybrid or A. triloba on casual observation. taxa. Based on personal observation, A. parvi- To resolve this problem, it was realized that 270 CASTANEA VOL.80

Figure 4. Vegetative and flowering buds of Asimina plants. (a) vegetative buds, both terminal and lateral (arrow) on Asimina triloba (photograph taken December 2014 at Lynch’s Woods, Newberry County, South Carolina), (b) vegetative (terminal) and flowering lateral bud (arrow) of Asimina 3 piedmontana (photo taken March 2008 at Lynch’s Woods, Newberry County, South Carolina). vegetative and floral buds look morphologically of the road (with a beaver-dammed pond) were different in late summer (by August). Vegetative only A. triloba plants and on the north side of buds (Figure 4a) are elongate (2–3 times longer the road were essentially only hybrid individuals. than wide), and floral buds (Figure 4b) are of Further, at this site most of the hybrid individ- about the same length and width. This observa- uals were 4 m tall and lacked arching stems. tion was confirmed in hybrid populations that Vegetatively, it was difficult to distinguish included plants about 2 m tall with floral buds. between a juvenile A. triloba and a mature Conversely, an A. triloba population with plants hybrid individual. This growth pattern was less than 3 m tall could be confidently identified similar to that seen at Lynch’s Woods, as if flower buds were absent on all stems. previously noted. Subsequent to the original floral field work, an As the hybrid nature of populations was unusual population was found on a slope at contemplated, the presence of the two parental Lynch’s Woods Park (Newberry County, South species was reviewed. At five of the six Carolina) that was identified as potentially of population sites for the hybrid, populations of hybrid origin. The population was not on a flood both A. parviflora and A. triloba were found plain, was somewhat clonal, individuals were 3– within 500 m of each other. This supported the 4 m tall, and leaves appeared to be smaller that hybrid nature of the two taxa. Looking at the would be expected for A. triloba. Analysis of leaf overall species distributions under the hybrid size showed a clear affinity with the hybrid. assumption, hybrid populations should be found Observation of flower morphology and size the in the region of species overlap. This area, as next spring supported the hypothesis of a hybrid seen from analysis of maps in Kral’s (1997) Flora origin of this population. of North America treatment, would include most At locations where species of Asimina were of North Carolina, the piedmont (northwestern found, commonly no physical overlap in the portion) of South Carolina, northern Georgia, three taxa was observed. Most commonly, A. northern Alabama, northern Mississippi, and triloba individuals were located on floodplains, northeastern Louisiana. A. parviflora individuals were on slopes well As a result of this work, the hybrid is hereby above the floodplain, and hybrids were at the designated. base of slopes, sometimes extending onto floodplains. However, at Padgett’s Creek (Union Asimina 3 piedmontana C. N. Horn, hybrid nov. (Figure 1 c–d). TYPE: USA, South Carolina, Laurens County, County, South Carolina) both A. triloba and the Enoree Rich Woods site to south of Enoree River. putative hybrid were found growing in proximity Floodplain to west of terminus of Forest Service road to one another. Even here some separation was 334, off of County 554. Sumter National Forest, 11 April seen in microhabitat, because on the south side 2009, Charles N. Horn 18587 (Holotype: USCH; isotypes: 2015 HORN: A NEW HYBRID OF ASIMINA 271

NCU, NBYC). Paratype for leaves and flower buds: same 1. Populations clonal, plants located on flood- location, 34833.4690N, 81845.8730W, Charles N. Horn plains or adjacent slopes, largest leaves mostly 20680, 16 August 2014 (CLEMS, NBYC, NCU, US, USCH) >18 cm long ...... 2 Hybrid between Asimina parviflora (Michx.) 2. Plants typically <2 m tall, largest leaves Dunal and Asimina triloba (L.) Dunal. Outer mostly <27 cm long ...... petals excurved at base. Differs from A. parvi- ...... Asimina 3 piedmontana flora in having peduncle length (6–) 8–12 mm 2. Plants typically more than 3 m tall (stems <3 m tall, lack flower buds in late (vs. 2–7 mm) and outer petal length 10–20 mm summer), largest leaves mostly >24 cm (vs. 3–8 [–10] mm). Differs from A. triloba in long ...... Asimina triloba having peduncle length (6–) 8–12 mm (vs. [9–] 11–19 mm) and outer petal width (12–) 15–27 ACKNOWLEDGMENTS A special thank mm (vs. 7–14 [–16] mm). you goes to Katherine Goodrich for initially Shrubs clonal, up to 3 m tall with branches pointing out a hybrid Asimina population and commonly arching. Vegetative buds elongate, suggesting the need for further research. Assis- valvate, with rusty pubescence. Leaves aromat- tance with field work was provided by Olivia ic,alternate,obovate,basecuneate,apex Hightower, Erica Deahl, C. Clinton Harshaw, acuminate to slightly caudate, glabrous above, Grace McCartha, and C. Hart Scott. Special rusty pubescent below, especially along veins, assistance with statistical analyses was obtained 13–31 cm long, 6–12 cm wide, petioles rusty from C. Clinton Harshaw (leaves and flowers). pubescent, 3–8 mm long. Flowers axillary, Floral measurements and preliminary data anal- solitary, developing before leaves; peduncle yses were completed by Jaimi Goodman as part rusty pubescent, 6–12 mm long. Sepals 3, of her research project at Newberry College slightly longer than wide with acute apex, (Newberry, South Carolina). Statistical analyses densely rusty pilose, 4–9 mm long. Petals 6, of leaf measurements were initially completed burgundy, in two series; outer petals elongate, by Olivia Hightower as part of her summer excurved near base, rusty on outer surface, 10– research experience at Presbyterian College 19 mm long, inner petals rounded, about one- (Clinton, South Carolina). John Wiersema edited half as long as the outer petals. Stamens many, an early version of this manuscript. An anony- spirally arranged, burgundy; carpels few, ovary mous reviewer helped improve the quality of the superior. Fruit not seen. original manuscript. In conclusion, a taxonomic key can be used to distinguish the three taxa when in flower, as LITERATURE CITED follows. DeLaney, K. 2010. Asimina manasota (Annona- ceae), a new pawpaw from west-central 1. Peduncle length 2–7 mm and outer petal length Florida, with notes on variation and natural 3–8 (10) mm ...... Asimina parviflora 1. Peduncle length (6–) 8–19 mm and outer petal hybridization within the genus. Bot. Explor. 4: length 10–25 mm ...... 2 1–68. 2. Peduncle length (6–) 8–12 mm and outer Horn, C.N. 2008. A flora of Lynch’s Woods Park, petal width 7–14 (16) mm; outer petals Newberry County, South Carolina. Castanea curved outward near base ...... 73(2):111–122...... Asimina 3 piedmontana 2. Peduncle length (9–) 11–19 mm and outer Kral, R. 1960. A revision of Asimina and petal width (12–) 15–27 mm; outer petals Deeringothamnus (Annonaceae). Brittonia curved outward near apex ... Asimina triloba 12(4):233–278. Use of leaf dimensions or other vegetative Kral, R. 1997. Annonaceae Jussieu, custard-apple features is not consistent enough to generate a family. In: Flora of North American Editorial reliable taxonomic key. However, leaf features, Committee (eds.). 1993þ.FloraofNorth along with habit and habitat, does produce a America North of Mexico. 12þ Vols. New York generally reliable key. and Oxford. Vol. 3, pp. 11–19.

1. Populations not clonal (although can be found Norman, E.M., K. Rice, and S. Cochran. 1992. in clumps), plants located on slopes or uplands, Reproductive biology of Asimina parviflora largest leaves mostly <22 cm long ...... (Annonaceae). Bull. Torrey Bot. Club 119(1): ...... Asimina parviflora 1–5. 272 CASTANEA VOL.80

Pomper, K.W., J.D. Lowe, L. Lu, S.B. Crabtree, Asimina 3 piedmontana and L.A. Collins. 2009. Clonality of Pawpaw *Laurens County, tributary to Enoree River (Asimina triloba) patches in Kentucky. J. north of terminus of Forest Service Road Kentucky Acad. Sci. 70(1):3–11. 334. Horn 18580 (flower), Horn 18764 Rohlf, F. 2009. NTSYSpc, Numerical Taxonomy (leaf) – H1 System, ver. 2.21. Exeter Software, Setauket, *#Newberry County, Lynch’s Woods Park, 1.0 mi New York. from park entrance along dirt road off of US 76. Horn 18118 (flower), Horn 18026 (leaf) – Ward, D.B. 2001. New combinations in the H2 Florida flora. Novon 11(3):360–365. *#Newberry County, Sulfur Spring Branch west Willson, M.F. and D.W. Schemske. 1980. Pollina- of Forest Service Road 391, 2.5 mi east of SC tor limitation, fruit production, and floral 121. Horn 18101 (flower), Horn 18886 (leaf, display in pawpaw (Asimina triloba). Bull. fruit) – H4 Torrey Bot. Club 107(3):401–408. #Union County, Johnson Creek east of Forest Zimmerman, G.A. 1941. Hybrids of the American Service Road 316, 1.5 mi south of junction pawpaw. J. Heredity 32:82–91. with unnumbered road between County Routes 278 and 156. Horn 18028 (leaf), Horn APPENDIX Populations from South Caroli- 18115 (flower) – H5 na sampled for leaf (*) and floral (#) measure- *#Union County, Padgetts Creek at County ments. Information in parenthesis after each Route 18, 2.1 mi west of junction with County collection number represents material visible on Route 16. Horn 18108 (flower), Horn 18847 the voucher; leaf, flower, or fruit. All voucher (leaf, fruit) – H3 specimens are deposited at the Newberry Col- #Union County, tributary to Broad River east of lege (Newberry, South Carolina) herbarium County Route 37, 4.8 mi south of junction with (abbreviation NBYC). The last component of SC 121 in Carlisle. Horn 18032 (leaf), Horn each location is the abbreviation used in the data 18113 (flower), Horn 18908 (leaf, fruit) – H6 graphs. Asimina triloba Asimina parviflora *Greenwood County, Tolberts Branch just *#Laurens County, Ned Wesson Branch north east of SC 248. Horn 18923 (leaf, fruit) – T5 of Forest Service Road 427, 1.4 mi north of SC 66. Horn 18035 (leaf), Horn 18110 *#Laurens County, floodplain of Enoree River (flower) – P4 north of terminus of Forest Service Road 334. *Laurens County, tributary to Duncan Creek Horn 18112 (flower), Horn 18589 (flower) – north of SC 66 opposite Forest Service Road T2 1071. Horn 18926 (leaf) – P5 *Newberry County, Lynch’s Woods Park, 1.5 mi *Laurens County, tributary to Duncan Creek from park entrance along dirt road off of US northwest of Forest Service Road 349B, 0.5 mi 76. Horn 18027 (leaf) – T1 southwest of County Route 26. Horn 18925 *Saluda County, Terrapin Creek at County Route (leaf) – P2 44, 3.3 mi west of pavement end. Horn 18683 *#Newberry County, Lynch’s Woods Park, 0.4 mi (flower), Horn 18911 (leaf, fruit) – T4 from park entrance along dirt road off of US #Union County, Fairforest Creek east of County 76. Horn 18103 (flower), Horn 18924 (leaf) – Route 16. Horn 18030 (leaf), Horn 18117 P3 (flower) – T7 #Union County, above tributary to Enoree River, *#Union County, Padgetts Creek at County southwest of Lee Cemetery and south of Route 18, 2.1 mi west of junction with County County Route 18. Horn 18034 (leaf), Horn Route 16. Horn 18031 (leaf), Horn 18107 18104 (flower) – P6 (flower), Horn 18846 (leaf, fruit) – T3 *Union County, tributary to Tyger River to west #Union County, tributary to Broad River east of of Forest Service road 325, 1.1 mi north of County Route 37, 4.8 mi south of junction with County Route 63. Horn 16593 (leaf, fruit), SC 121 in Carlisle. Horn 18033 (leaf), Horn Horn 18927 (leaf) – P1 18114 (flower) – T6