Crataegus rhodamae-loveae T.A. Dickinson, 2023

Crataegus rhodamae-loveae T.A. Dickinson View in CoL , sp. nov. ( Figs. 8C View FIG , 10 View FIG , 11 View FIG , 12 View FIG ). TYPE: U.S.A. OREGON. Jackson Co.: N side of Lampman Road above Rogue River , ca. 80 m NE of the junction with Highway 99, Aug 2011, J. C. Coughlan, H. Moothoo , & C. Shaw JC 039 (HOLOTYPE: TRT00020284 About TRT !) .

= Crataegus suksdorfii (Sarg.) Kruschke View in CoL sensu lato in part; = C.gaylussacia sensu J.B. Phipps (2013 View in CoL , 2015) in part.

= Crataegus brevispina Douglas ex Steud., Nomencl. Bot. (Steudel) View in CoL ,ed.2,1:432.1840, nom. inval.

= Crataegus punctata var. brevispina Douglas ex Hook., Fl.Bor.-Amer.(Hooker) View in CoL 1(4):201 (1832).( Fig. 10 View FIG ).

Diagnosis.— Differing from the two other members of Crataegus ser. Douglasianae with approximately 20 stamens per flower, C. gaylussacia A. Heller and C. × suksdorfii (Sarg.) Kruschke , in being predominantly a sexual, pollen-fertile diploid (2 n = 34) rather than an apomictic polyploid; thorns shorter and narrower, 7–12 mm long, 1.5–2.5 mm wide at base; leaf marginal teeth coarser, 6–9 per 1.0 cm adjacent leaf apex, than those of C. × suksdorfii ; leaves variable in shape, but overall long-elliptic, often longer below the widest point (obovate;0.7–1.0 × width) than in the other species discussed here.Found west of the Cascades in Oregon and adjacent California and Washington, mostly at lower elevations (10–1,000 m ASL) than C. × suksdorfii , allopatric with the other species discussed here; also autopolyploids (2 n = 51, 68) on the western slopes of the Cascades in Oregon (1,200 –1,350 m ASL).

Description.— Trees or shrubs to 7 (–12) m, bark orange-brown on young twigs, becoming gray with age, smooth, but on trunks and large branches flaking irregularly. Thorns 7–12 mm long, straight, 1.5–2.5 mm in diameter at the base. Leaves (microphylls–) notophylls, unlobed (occasionally pinnately lobed), singly to doubly serrate, 6–9 teeth per cm adjacent leaf apexsurfaces pubescent, glabrescent, or glabrous, petioles 11–14 mm long. Flowers with calyx lobes 1–2 mm long, not toothed, stamens 15–20, free, undehisced anthers pink at anthesis, 4–5 styles. Dried fruits 4–7 mm in diameter, purple-black at maturity, with persistent calyx lobes. For images of the type material see https://morphobank.org/permalink/?F1092.

Distribution.— Populations of diploid Crataegus rhodamae-loveae are found west of the Cascades summit ( Fig. 3 View FIG ; Fig. 1 View FIG and 9 View FIG in Dickinson et al. 2021), at elevations less than 100 m ASL, apart from ones in Rogue River drainage in Jackson and Josephine Counties, Oregon (300 - 400 m ASL), and those in northwestern California (to 1,000 m ASL). Autopolyploids are found in Oregon at elevations 1,000 –1,250 m ASL. These locations correspond to the following ecoregions ( Anonymous 2010; Griffith et al. 2016; Thorson et al. 2003): Willamette Valley (Oregon, Washington), Cascades (California, Oregon, Washington), Eastern Cascades Slopes and Foothills (California), and Klamath Mountains (California, Oregon).

Remarks.— Both Crataegus rhodamae-loveae and C.douglasii were collected by David Douglas on his first trip to the Pacific Northwest, 1825–1827, as is shown by his three sheets of specimens at Kew. In writing up Douglas’ collections in the Flora boreali-americana, W.J. Hooker (1832) observed, “Two varieties are in Mr. Douglas’s collection from the North-West coast; both, indeed, with short thorns; one is glabrous in every part, the other has the peduncles, calyces, and under-side of the leaves downy.” The type of C. douglasii (K000442061) is from a tree grown from at the Horticultural Society of London from seeds collected by Douglas in 1826, near the confluence of the Spokane and Columbia rivers ( Douglas 1914). Flowers and pedicels on this specimen are glabrous. Maceration of three anthers in Alexander’s stain showed virtually all pollen grains to be doubly stained, hence fertile (compare Fig. 6 View FIG ). A second sheet has one specimen (K000442063) labelled “Columbia [John] Scouler,” and four more attributed to David Douglas. There are two labels, Crataegus punctata , and Crataegus punctata var. brevispina , corresponding to the entry in W.J. Hooker’s Flora boreali-americana Volume 1, Part 4 ( Hooker 1832). The first label is associated with three specimens (K000442064, K000442065, K000442066) that have flowers with approximately 10 stamens per flower. The Crataegus punctata var. brevispina label is next to the fourth specimen (K000442062) and both it and the Scouler specimen have about 20 stamens per flower. This fourth specimen has pubescent pedicels and pollen grains from anthers macerated in Alexander’s stain were also almost entirely double stained. The third sheet (K000370425) bears four leafy inflorescences collected by Douglas in 1825 “near the confluence of the Columbia” and is labelled as Crataegus sanguinea var. douglasii Torr. & A. Gray. All four have flowers with pubescent pedicels and hypanthia, and (15–)20 stamens per flower. Twenty-five pollen grains from anthers of one specimen ( Fig. 10 View FIG ) were all doubly stained, with no sign of any empty grains. The pubescent pedicels were an early indication that specimens collected in Columbia County, Oregon, and Clark County, Washington, by Peter Zika in 2003 with around 20 stamens per flower were different from other C. suksdorfii sensu lato material studied up until then. These and other specimens from the same and nearby sites were the first C. suksdorfii sensu lato individuals shown to be diploids ( Talent & Dickinson 2005). Subsequent collections from elsewhere in the diploid range showed that the correlation between diploidy and pubescence was not constant. However, this does suggest that the pollen-fertile 20-stamen C. suksdorfii sensu lato specimens collected by David Douglas probably came from forays he made in the vicinity of Fort Vancouver after his arrival there in early April 1825, and so are likely to represent the first specimens of Crataegus rhodamae-loveae .

Etymology.— Diploid C. suksdorfii sensu lato is named as a new species in honor of Oregon botanist and historian of Pacific Northwest botany, Rhoda M. Love (1932–2022; pp. 19–20 in Meyers et al. 2015). Rhoda Love was the first to study North American hawthorn reproductive biology by means of pollination experiments, introduced the first author to the Oregon flora, and became a valued mentor and colleague. In naming this species we explicitly disagree with Guedes et al. (2023) that eponyms should be avoided. Rather, eponyms can reflect the involvement of the honoree with the plant being named. Such names are an important way for taxonomists to recognize the contributions of others to their work and to the study and preservation of plants and their habitats. This represents an important social dimension of taxonomy that should weigh against possible adverse cultural and political uses of eponyms.

Ploidy level.— Diploids, 2n = 34; also autopolyploids, 2n = 51 and 68, based on chromosome counts ( Dickinson et al. 1996) and flow cytometric determinations of nuclear DNA content (N. Talent unpubl. data; Coughlan et al. 2014; Lo et al. 2013; Talent & Dickinson 2005), and analyses of nuclear and plastome DNA sequences ( Lo et al. 2009b; Lo et al. 2010; Zarrei et al. 2014).

Hybrid.— Crataegus × cogswellii K.I.Chr. & T.A. Dickinson (= ♀ Crataegus rhodamae-loveae (diploid C. suksdorfii ) × ♂ C. monogyna ) PhytoKeys 36:19 (2014). Individuals with pinnately lobed leaves may represent monogyna introgression. For exemplars, see https://morphobank.org/permalink/?F1097.

Conservation Status.— Introgression from sympatric C. monogyna could erode the genetic integrity of Crataegus rhodamae-loveae .

Paratypes: U.S.A. CALIFORNIA. Siskiyou Co.: T41 N R9 W S3 N side of Fay Lane , 28 Jul 2006, T. A . Dickinson & E. Y. Y . Lo 2006-19 ( TRT00001569 About TRT ); Fay Lane , 28 Jul 2006, T. A . Dickinson & E. Y. Y . Lo 2006-20 ( TRT00020296 About TRT ); T41 N R9 W S3 N side of Fay Lane , 28 Jul 2006, T. A . Dickinson & E. Y. Y . Lo 2006-22 ( TRT00001563 About TRT ) . OREGON. Columbia Co.: Sauvie I , just N of Columbia-Multnomah county line, 20 Aug 2011, J . Coughlan , H . Moothoo ,& C . Shaw,JC 119 ( TRT00020235 About TRT ); Sauvie I , just N of Columbia-Multnomah county line, 18 May 2011, J . Coughlan , M. Zarrei , & C . Shaw JC 114 ( TRT00020171 About TRT ); Diblee Pt. , 20 May 2011, J . Coughlan , M. Zarrei , & C . Shaw JC 136 ( TRT00020242 About TRT ); Sauvie I , just N of Columbia-Multnomah county line, 2 May 2010, J . Shiller , J . Tusha , T. A . Dickinson , & M . Heckel 2010-13 ( TRT00002011 About TRT ); T7 N R2 W S6 , Diblee Pt. , 18 Sep 2003, P. F . Zika 19064 ( TRT00001689 About TRT ) . Douglas Co.: Upper Elk Meadow , 26 May 1987, R. M . Love 8766 ( TRT00001668 About TRT ); Upper Elk Meadow , 29 Jun 2003, R. M . Love C-2003-39 ( TRT00001669 About TRT ) . Hood River Co.: Cascade Locks , 20 Aug 2011, J . Coughlan , H . Moothoo ,& C . Shaw JC092 ( TRT00020154 About TRT ) . Josephine Co.: Deer Creek Centre, Deer Creek, at confluence of Squaw Creek , 12 May 2011, J . Coughlan M. Zarrei , & C . Shaw JC045 ( TRT00020323 About TRT ) . Lane Co.: Patterson Mt. Prairie , 9 Jun 2004, E. Y. Y . Lo , T. A . Dickinson , S . Nguyen , & R. M . Love EL 65 ( TRT00001760 About TRT ); Patterson Mt. Prairie , 9 Jun 2004, E. Y. Y . Lo , T. A . Dickinson , S . Nguyen , & R. M . Love EL52 ( TRT00001656 About TRT ) . Linn Co.: Corvallis,KOA Campground , Aug 2011, J . Coughlan , H . Moothoo , & C . Shaw JC060 ( TRT00020147 About TRT ); Cogswell- Foster Reserve , 10 Jun 2004, E. Y. Y . Lo , T. A . Dickinson , & S . Nguyen EL68 ( TRT00001724 About TRT ) . Multnomah Co.: 1.5 km NE of Troutdale , 20 Aug 2011, J . Coughlan , H . Moothoo , & C . Shaw JC098 ( TRT00020160 About TRT ); 1.5 km NE of Troutdale , 20 Aug 2011, J . Coughlan , H . Moothoo , & C . Shaw JC099 ( TRT00020162 About TRT ); 1.5 km NE of Troutdale , 20 Aug 2011, J . Coughlan , H . Moothoo , & C . Shaw JC102 ( TRT00020164 About TRT ); 1.5 km NE of Troutdale , 20 Aug 2011, J . Coughlan , H . Moothoo , & C . Shaw JC103 ( TRT00020166 About TRT ); 1.5 km NE of Troutdale , 20 Aug 2011, J . Coughlan , H . Moothoo , & C . Shaw JC 104 ( TRT00020372 About TRT ). OREGON or WASHINGTON: near the confluence of the Columbia , 30 Apr 1825, D. Douglas, s.n. ( K000370425 ); near Ft. Vancouver, 30 Apr 1825, D. Douglas s.n. ( K000442062 ); near Ft. Vancouver, 30 Apr 1825, D. Douglas s.n. ( K000442064 ) . WASHINGTON. Clark Co.: T4 N R1 W S13 , ca. 1.5 air mi NNW of Ridgefield , 15 Jun 2003, P . Zika 18485 ( TRT00001805 About TRT ); T4 N R1 E S5, 4 air mi NE of Ridgefield , 15 Jun 2003, P . Zika 18486 ( TRT00001808 About TRT ) .

Appendix 1. Vouchers for morphometric data.

Appendix 2. Vouchers for microsatellite data.

Appendix 3. Vouchers for data on the density of leaf marginal teeth were collected.

Appendix 4. Vouchers for pollen stainability data.

These appendices will be made available as part of MorphoBank Project P832.