Plant Syst. Evol. 234: 137–153 (2002) DOI 10.1007/s00606-002-0195-z Tribes of Boraginoideae (Boraginaceae) and placement of Antiphytum, Echiochilon, Ogastemma and Sericostoma: A phylogenetic analysis based on atpB plastid DNA sequence data E. La˚ ngstro¨ m1 and M. W. Chase2 1Department of Systematic Botany, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden 2Jodrell Laboratory, Royal Botanic Gardens, Kew, UK Received November 27, 2001; accepted March 20, 2002 Published online: November 14, 2002 Ó Springer-Verlag 2002 Abstract. The genera Antiphytum, Echiochilon, Og- ships for Boraginaceae (in the euasterid I astemma and Sericostoma, which have been difficult clade) are uncertain, as either Gentianales, to place within the tribes of the subfamily Bora- Lamiales, Solanales, or various combinations ginoideae (Boraginaceae), are analysed using plas- of these orders could be the sister to Boragin- tid atpB sequence data. A selection of Boraginaceae aceae (Olmstead et al. 2000, Savolainen et al. genera was used to obtain a framework for the 2000, Soltis et al. 2000, Albach et al. 2001). phylogenetic position of Antiphytum, Echiochilon, Hydrophyllaceae is a mainly new world Ogastemma and Sericostoma. Sericostoma is found to belong within Echiochilon. The new tribe family of herbs and shrubs with ca 18 genera Echiochileae, Boragineae and Lithospermeae are and 270 species (Mabberley 1997), character- monophyletic but the tribes Eritrichieae and ised by capsular fruits. Boraginaceae and Cynoglosseae are paraphyletic. The biogeography Hydrophyllaceae have long been considered of Echiochileae (Echiochilon and Ogastemma from to be closely related, and recent molecular Africa and western Asia, and Antiphytum from studies using rbcL indicate that Hydrophylla- America) is discussed. ceae is nested within Boraginaceae s. lat. (e.g. Olmstead et al. 1992, 1993; Chase et al. 1993). Key words: Antiphytum, Echiochilon, Ogastemma, This was supported by a more inclusive study Sericostoma, Boraginaceae, Echiochileae phylo- of Hydrophyllaceae based on ndhF sequence geny, atpB, tribes, biogeography. data (Ferguson 1999), and by phylogenetic analysis of the secondary structure of ITS1, Boraginaceae is a family of herbs, shrubs and (Gottschling et al. 2001), which also supported trees with a cosmopolitan distribution. The the inclusion of the new world parasitic family comprises ca 130 genera and 2300 family Lennoaceae in Boraginaceae s. lat. species (Mabberely 1997). Boraginaceae has Consequently, the Boraginaceae subfamilies for a long time provided a set of controversial Cordioideae, Ehretioideae, Heliotropioideae, phylogenetic problems at different taxonomic Boraginoideae (recognised mainly on gynoe- levels. For example, the sister group relation- cium characters; e.g. Gu¨ rke 1897) and Well- 138 E. La˚ ngstro¨ m and M. W. Chase: Boraginoideae stedioideae (sensu Pilger 1912) are by some Verdcourt (1991) tentatively placed Echiochi- authors treated as families (e.g. Hutchinson lon in Eritrichieae. Until Johnston (1957), none 1969, Heywood 1993, Gottschling et al. 2001, of the species of Echiochilon with actinomor- Diane et al. 2002). In this article Boraginaceae phic flowers were placed in Echiochilon but is used for the family in its widest sense. rather in Sericostoma s. lat. (Table 1). Boraginoideae, the largest subfamily of Sericostoma was until 1967 mostly placed Boraginaceae, has variously been divided into in Lithospermeae and Echiochilon in Echieae, 4–c. 20 tribes (e.g. Popov 1953, 12 tribes), even Eritrichieae or Lithospermeae, but Johnston though most authors have accepted only four (1957) suggested that Echiochilon, Ogastemma to seven tribes (Table 1). Some authors have and Sericostoma are closely related to each recognised the tribe Echieae (de Candolle other and to the New World genus Antiphy- 1846, Baillon 1888, Gu¨ rke 1897, Popova and tum. In 1967, Riedl formed the new tribe Zemskova 1995, Retief and Van Wyk 1997). Trigonotideae (Riedl 1967) in which he includ- De Candolle (1846) and Popova and ed Sericostoma s. str. among other genera. He Zemskova (1995) used the monogeneric tribe also included Antiphytum in his new tribe, but Cerintheae and de Candolle (1846) did not kept Echiochilon in Eritrichieae. Riedl did not recognise the tribe Eritrichieae and treated the mention Ogastemma, which traditionally has species usually included in Eritrichieae as been placed in Eritrichieae, in his early Cynoglosseae. Trigonotideae circumscriptions (Riedl 1967, Examples of genera with uncertain posi- 1968) but in a later treatment he included tions within Boraginoideae are Antiphytum Ogastemma in Trigonotideae (Riedl 1997). DC. ex Meisn., Echiochilon Desf., Ogastemma The gene used in this study, atpB, is a Brummitt and Sericostoma Stocks ex Wight. plastid gene that codes for the beta subunit of They are here treated together because mor- ATP synthase. It has been used for recon- phological characters indicate that they might struction of angiosperm phylogeny in several be closely related (Johnston 1957). Echiochilon, groups and has been useful in shedding light Ogastemma and Sericostoma were morpholog- on problems similar to those addressed in this ically revised by Lo¨ nn (1999). They grow in study (Hoot et al. 1995, Hoot et al. 1997, dry, sandy, stony or rocky habitats ranging Chase et al. 1999). The gene atpB has a similar from Fuerteventura of the Canary Islands rate of evolution to that of rbcL (Hoot et al. (only Ogastemma) over northwestern Africa, 1995, Savolainen et al. 2000). northern Africa, the Horn of Africa, the The major goals of this paper are to Arabian Peninsula and along the coast to investigate the phylogenetic positions of An- India (only Sericostoma; detailed maps in tiphytum, Echiochilon, Ogastemma and Seri- Lo¨ nn 1999). costoma within Boraginaceae (including the Echiochilon has been variously allocated to interrelationships of the genera) by sampling three different tribes, Echieae, Eritrichieae and the subfamilies of Boraginaceae, the tribes of Lithospermeae. Some authors (e.g. Baillon Boraginoideae and putative close relatives 1888, Verdcourt 1991) have clearly expressed of Antiphytum, Echiochilon, Ogastemma and their doubts regarding the tribal position of Sericostoma. Echiochilon. Baillon (1888) for instance wrote that Echiochilon could artificially be assigned to Echieae, but in some characters (nutlet Material and methods characters) it shows similarities with the mem- DNA extraction. Total genomic DNA was extract- bers of Eritrichieae. Johnston (1924) placed ed from fresh or silica-gel dried leaves, seeds or Echiochilon in Lithospermeae but later (John- herbarium material, using a modification of the 2X ston 1957) stated its relationships to be CTAB extraction protocol of Doyle and Doyle unclear. Sauvage and Vindt (1954) and (1987). The DNA was purified by CsCl2–ethidium Table 1. Tribal treatment in Boraginoideae by selected authors to show how the genera in Echiochileae have been placed by those authors (small E. La capitals). Genera marked with bold style are the genera selected for the phylogenetic analysis in this paper. All taxa mentioned by these authors ˚ are listed, so there are some synonyms in the list and also some genera now belonging to other families. Authors not accepting Echieae have ngstro included those species in Lithospermeae. Only de Candolle (1846) recognised Cerintheae as a tribe (not shown here); he also treated the species ¨ usually included in Eritrichieae as Cynoglosseae. Takhtajan (1997) only gave a few examples for each tribe m and M. W. Chase: Boraginoideae 139 Tribes accepted Boragineae Cynoglosseae Echieae Eritrichieae Lithospermeae Myosotideae Trigonotideae Trichodesmeae Author (Borageae/ Anchusae) De Candolle Anchusa Amsinckia ECHIOCHILON Alkanna 1846 Borago ANTIPHYTIM Echium Arnebia Caryolopha Caccinia Lobostemon Bothriospermum Lycopsis Craniospermum Macrotomia Colsmannia Moritzia Cynoglossum Lithospermum Nonea Diploloma Macromeria Psilostemon Echinospermum Maharanga Stomotechium Eritrichium Meratia Symphytum Gruvelia Mertensia Heterocaryum Moltkia Krynitzkia Myosotis Mattia Onosma Omphalodes Onosmodium Pectocarya Pentalophus Plagiobothrys Pulmonaria Rindera Stenosolenium Solenanthus Suchtelenia Trichodesma Bentham & Alkanna Actinocarya Amsinckia Ancistrocarya Hooker 1873 Anchusa Caccinia Asperugo ANTIPHYTUM Borago Cynoglossum Bothriospermum Arnebia Lycopsis Harpagonella Craniospermum Cerinthe Nonea Heliocarya Echidiocarya Echium Pulmonaria Lindelofia ECHIOCHILON Lithospermum Symphytum Myosotidium Echiochospermum Lobostemon Table 1 (continued) 140 E. La Tribes accepted Boragineae Cynoglosseae Echieae Eritrichieae Lithospermeae Myosotideae Trigonotideae Trichodesmeae Author (Borageae/ Anchusae) Trachystemon Omphalodes Eritrichium Macromeria Trigonocaryum Paracaryum Gastrocotyle Macrotomia Pectocarya Microula Megacaryon Rindera Rochelia Mertensia Solenanthus Moltkia Suchtelenia Morizia Thyrocarpus Myosotis Trichodesma Onosma Onosmodium SERICOSTOMA Trigonotis Zwackhia Baillon 1888 Alkanna Actinocarya ECHIOCHILON Actinocarya Ancistrocarya Anchusa Caccinia Echium Allocarya ANTIPHYTUM Borago Cynoglossum Lobostemon Amsinckia Arnebia Lycopsis Heliocarya Zwackhia Asperugo Brachybotrys Oskampia Kuschakewiczia Bothriospermum Cerinthe ˚ Pulmonaria Lindelofia Craniospermum Cystostemon ngstro Symphytum Myosotidium Cryptantha Lithospermum Trachystemon Omphalodes Eremocarya Macromeria ¨ m and M. W. Chase: Boraginoideae Trigonocaryum Paracaryum Eritrichium Macrotomia Pectocarya Gastrocotyle