Johnstonella echinosepala (Macbride, 1918) Hasenstab & Simpson, 2012

Simpson, Michael G. & Rebman, Jon P., 2021, Research in Boraginaceae: A new variety of Cryptantha maritima, Cryptantha pondii resurrected, and Johnstonella echinosepala transferred back to Cryptantha, Phytotaxa 509 (2), pp. 185-210 : 199

Transfer of Johnstonella echinosepala back to Cryptantha

The genus Johnstonella was resurrected by Hasenstab-Lehman & Simpson (2012), who added to the two originally described species of the genus— J. inaequata Brand (1925: 249) and J. racemosa Brand (1925: 249) —by making 11 new combinations, one of these Johnstonella echinosepala . However, of these 13 species in the genus, only eight had been sequenced and verified from molecular phylogenetic evidence to be part of the same clade, Johnstonella echinosepala not among these. The basis for transferring this species to Johnstonella was morphology of the nutlets, those of J. echinosepala being heteromorphic with whitish tubercles (in the consimilar nutlets), similar to many other members of Johnstonella .

The subsequent molecular phylogenetic study of Simpson et al. (2017a) expanded the study of Johnstonella by sequencing 11 of the 13 species, verifying that Johnstonella constitutes a well-supported clade separate from the genus Cryptantha . These authors also noted additional species of Cryptantha grouping with Johnstonella , four of these later transferred to the latter genus ( Simpson et al. 2019). However, two species that had been placed in Johnstonella originally by Hasenstab-Lehman & Simpson (2012) based on morphology, but not sequenced by them, did not fall into the Johnstonella clade in the later study, these being J. echinosepala , which grouped with Cryptantha maritima of their Maritimae clade (see below) and J. micromeres ( Gray 1883: 90) Hasenstab & Simpson (2012: 754) , which grouped within Cryptantha s.s.

Morphologically, Johnstonella echinosepala does resemble other members of that genus in having nutlets that are heteromorphic (a condition found in a total of eight species of the genus, including J. echinosepala ) and in having a white-minutely tuberculate nutlet sculpturing, although the latter feature is restricted to the three smaller, consimilar nutlets. However, we point out that the consimilar nutlets of J. echinosepala are also rather similar in shape and sculpturing to the “rough” nutlets (when present) of Cryptantha maritima ; e.g., compare Fig. 1C or 4C with Fig. 9C . Additionally, J. echinosepala and all varieties of C. maritima , including our newly named C. m. var. vizcainensis , as well as C. pondii have the odd nutlet in the “axial” position, i.e., closest to the inflorescence axis ( Johnston 1925, 1928, current study). In contrast, all of the other heteromorphic species of Johnstonella — J. angelica ( Johnston 1924: 1143) Hasenstab & Simpson (2012: 754) , J. angustifolia ( Torrey 1857: 363) Hasenstab & M.G.Simpson (2012: 754) , J. diplotricha (Philippi 1891: 57) Hasenstab & Simpson (2012: 754) , J. fastigiata ( Johnston 1939: 388) Hasenstab & Simpson (2012: 754) , J. inaequata , J. parviflora (Philippi 1860: 39) Hasenstab & Simpson (2012: 754) , and J. racemosa —have the odd nutlet positioned in the abaxial position, i.e. away from the inflorescence axis ( Johnston 1925, 1927, 1939).

The most recent molecular phylogenetic analysis, along with our observations based on morphology (including nutlet position), argue that Johnstonella echinosepala should be transferred back to the genus Cryptantha . Thus, we accept Cryptantha echinosepala as the correct name for this species.

Figures

FIGURE 1. Exemplars of three varieties of Cryptantha maritima. A–C.Cryptantha m. var. maritima.A. Image of original material: Greene s.n., 26 Apr 1885, Mexico, Baja California, Guadalupe Island (UC193934). Note bracts and hispid vestiture. B. Field image, showing bracts and small corollas; photograph by Jon Rebman, 2 April 2008, Mexico, Baja California Sur, Laguna San Ignacio. C. Nutlets of fruit, one larger smooth (left) and one smaller tuberculate (right), from Simpson 2933 (SDSU19298). D, E. Cryptantha m. var. cedrosensis. D. Field image, showing larger corolla of this variety; photograph by Jon Rebman, 31 March 2015, Mexico, Baja California, Cedros Island. E. Fruiting calyx with four nutlets dissected out, these heteromorphic with one larger smooth and three smaller tuberculate; from Rebman 2446, 17 March 1994 (HCIB6234). F–H. Cryptantha m. var. pilosa. F. Field image, showing bracts, dense tufts of hirsute trichomes, and small corollas; photograph courtesy of Pablo Ruiz, United States, Pima County, Arizona, Saguaro National Park, iNaturalist observation 39812503. G, H. Images from C.V. Morton 2061, 19 March 1949 (SD113111). G. Close-up of flowers and fruits, showing calyces with dense tufts of whitish, ascending hirsute trichomes, characteristic of this variety. H. Solitary nutlet of fruit, this smooth.

FIGURE 9. Cryptantha echinosepala [Johnstonella e.] fruit of exemplar, León 3465, 15 March 2003 (SD153719). A. Fruit with four heteromorphic nutlets removed.Note relatively small, persistent corolla. B. Close-up of large “odd” nutlet, in dorsal (left), ventral (middle), and side (right) views. Note tuberculate-spinulose sculpturing. C. Close-up of one of the small “consimilar” nutlets, in dorsal (left), ventral (middle), and side (right) views. Note tuberculate sculpturing, lacking spinules.