THE GENUS GERANIUM L. (GERANIACEAE) IN NORTH AMERICA. II. PERENNIAL SPECIES by CARLOS AEDO Real Jardín Botánico, CSIC. Plaza de Murillo, 2. E-28014 Madrid ([email protected]) Resumen AEDO, C. (2001). El género Geranium L. (Geraniaceae) en Norteamérica. II. Especies perennes. Anales Jard. Bot. Madrid 59(1): 3-65 (en inglés). Se revisan las especies perennes de Geranium de Norteamérica al N de México. Se aceptan 19 especies de las cuales 17 pertenecen al subg. Geranium y dos al subg. Robertium. Geranium erianthum, G. maculatum, G. oreganum, G. sylvaticum, G. caespitosum, G. californicum, G. lentum, G. wislizenii, G. richardsonii, G. viscosissimum son las especies autóctonas, y G. pratense, G. sanguineum, G. potentilloides, G. sibiricum, G. thunbergii, G. retrorsum, G. solanderi, G. pyrenaicum y G. palmatum, las introducidas tanto desde Europa como desde Asia u Oceanía. Geranium eremophilum, G. fremontii, G. parryi, G. marginale y G. cowenii, a veces aceptados en la literatura reciente, son considerados como sinónimos de G. caespitosum. Del mismo modo, se sinonimiza G. strigosum y G. attenuilobum a G. viscosissimum y G. concinnum a G. californicum. Se revisa la nomenclatura de todas las especies y se designan diecisiete lectótipos. Se incluyen descripciones completas, una clave, mapas de distribución e ilustraciones. Palabras clave: Geranium, Geraniaceae, taxonomía, tipificaciones, Norteamérica. Abstract AEDO, C. (2001). The genus Geranium L. (Geraniaceae) in North America. II. Perennial species. Anales Jard. Bot. Madrid 59(1): 3-65. Perennial species of Geranium from North America north of Mexico are revised. Nineteen species are accepted, of which seventeen belong in subg. Geranium and two belong in subg. Robertium. Geranium erianthum, G. maculatum, G. oreganum, G. sylvaticum, G. caespito- sum, G. californicum, G. lentum, G. wislizenii, G. richardsonii, G. viscosissimum are native, whereas G. pratense, G. sanguineum, G. potentilloides, G. sibiricum, G. thunbergii, G. retrorsum, G. solanderi, G. pyrenaicum and G. palmatum were introduced from Europe, Asia, and Oceania. Geranium eremophilum, G. fremontii, G. parryi, G. marginale and G. cowenii, sometimes accepted in current literature, are considered to be synonyms of G. caespitosum. Similarly, G. strigosum and G. attenuilobum are synonymized to G. visco- sissimum, and G. concinnum to G. californicum. Nomenclature for all species is reviewed, and seventeen lectotypes are designated. Descriptions, key, distribution maps, and illustra- tions are included. Key words: Geranium, Geraniaceae, taxonomy, typification, North America. 4 ANALES JARDÍN BOTÁNICO DE MADRID, 59(1) 2001 INTRODUCTION MATERIALS AND METHODS The study of Geranium from North Ameri- This revision is based on more than 2000 ca has been divided in two parts for operative herbarium specimens from the following reasons. The first part, including annual (and herbaria: ARIZ, BM, CAN, CM, COLO, biennial) species was published in AEDO DAO, F, GH, ILL, JEPS, K, LE, MA, (2000). The second part revising perennial MEXU, MICH, MIN, MO, MSC, NEB, species is presented here. NMC, NY, OKL, P, PH, SD, TEX, UC, General information about North Ameri- UNM, US, V, VT, W, and WTU. Further- can Geranium was given in the introduction more, microfiches, photographs, and other of AEDO (2000), and is not repeated. Addi- material have been examined from BM and tionally, the study by JONES & JONES (1943) LINN. Curators from ALTA, ACAD, should be remarked. These authors revised BRY, MOAR, UAT, and UBC, kindly an- perennial species from the United States and swered our petition, but they did not find Canada. They considered eighteen species any of the requested specimens in their from which only one was introduced herbaria. (G. pratense). Their treatment is more ana- The ten native species have been rather lytic, since they split G. caespitosum in six thoroughly studied in some aspects such as species, G. viscosissimum in three species, morphology, synonymy, and distribution. In and G. californicum in two species. those native species, a search for micromor- Geranium comprises in the area of North phological characters has been carried out us- America flora 30 species (both annuals and ing scanning electron microscopy (SEM). perennials), of which 23 belong in subg. Samples were glued to aluminium stubs, coat- Geranium and 7 belong in subg. Robertium. ed with 40-50 nm gold, and examined with a All native species (13) belong in subg. Gera- JEOL-TSM T330A scanning electron micro- nium. Among the 17 introduced species, 10 scope at 15 kV. belong in subg. Geranium and 7 belong in Short glandular hairs (<40 µm long), usu- subg. Robertium. From these introduced ally constituted by two cells (although they species 13 have arisen from the Old World sometimes have a bicellular foot, Fig. 1f), (Europe and neighbouring areas), 3 from are present in all species here studied but Oceania, and 1 from East Asia. they are not considered in descriptions Some remarks should be also made about since they are only evident at high magnifi- the distribution of native perennial species. cation. Two of them also occur in another conti- For introduced species only synonyms de- nent: G. erianthum in Asia, G. sylvaticum in scribed from North America are indicated, Europe. Among the remaining, two are while a comprehensive synonymy is provided widespread in North America, one is re- for natives ones. stricted to the Eastern half of the continent, The area covered in this paper includes and eight are restricted to the opposite half. North America north of Mexico plus Green- Thus, the Rocky Mountains and western ar- land, since this study has been carried out for eas seem to be the richest in Geranium the Flora of North America project, which in- species. The number of endemic species is cludes the above mentioned area. For eight eight. Geranium caespitosum, G. caroli- native Geranium, maps cover the total range nianum, and G. wislizenii have their Southern of the each species. However, for G. erian- limit in Mexico. Finally, six species do not thum and G. sylvaticum maps only include occur in Canada: G. caespitosum, G. cali- American localities. For the introduced fornicum, G. lentum, G. oreganum, G. te- species maps are restricted to its North Ame- xanum, and G. wislizenii. rican area. C. AEDO: THE GENUS GERANIUM L. IN NORTH AMERICA. II 5 Fig. 1.–SEM photomicrographs showing indumentum of some perennial Geranium native from North America: a, pedicel of G. erianthum [Calder 5411 (DAO)]; b, pedicel of G. viscosissimum [Peck 18320 (ORE)]; c, apex of a glan- dular hair on the sepal of G. maculatum [Ahles 82611 (VT)]; d, apex of a glandular hair on the pedicel of G. viscosissi- mum [Peck 18320 (ORE)]; e, pedicel of G. maculatum [Ahles 82611 (VT)]; f, small glandular hair on the pedicel of G. caespitosum [Spellenberg 6324 (NMC)]. 6 ANALES JARDÍN BOTÁNICO DE MADRID, 59(1) 2001 KEY TO THE SPECIES 17. Nectarious dorsally lanate; petals usually white .......................................... 16. G. richardsonii 1. Cymules 1-flowered ...................................... 2 17. Nectarious with a tuft of hairs at the top, dor- 1. Cymules 2-flowered ...................................... 4 sally glabrous; petals white or pink ............. 18 2. Petals more than 15 mm long ........................... 18. Ratio fruit length / stigmatic remains length = ............................................ 6. G. sanguineum 6-8.2; basal leaves 7.1-16 cm wide .................. 2. Petals 5-10 mm long ..................................... 3 ...................................... 17. G. viscosissimum 3. Leaves with middle segment obtriangular, 3 18. Ratio fruit length / stigmatic remains length = (-5)-lobed at the apex ...... 7. G. potentilloides 3.8-5.5; basal leaves 3-7.5 cm wide ............ 19 3. Leaves with middle segment rhombic, 7-9- 19. Fruit 22-31(-33) mm long; rostrum with nar- lobed in the distal half............. 8. G. sibiricum rowed apex 2-4 mm long; petals usually purplish; 4. Mericarps without basal callus ...................... 5 pedicels short (1.8-12 cm) ... 12. G. caespitosum 4. Mericarps with basal callus ........................... 7 19. Fruit 32-42 mm long; rostrum with narrowed 5. Petals 7-11 mm long ........ 18. G. pyrenaicum apex 5-6 mm long; petals usually white; pedicels 5. Petals 19-30 mm long .................................... 6 long (2.2-24 cm) ............... 13. G. californicum 6. Mericarps reticulate ............ 19. G. palmatum 6. Mericarps smooth ............... G. × magnificum TAXONOMY 7. Petals glabrous on the adaxial surface, ciliate at the base .......................................................... 8 I. Geranium subg. Geranium 7. Petals hairy on 1/3-3/4 of their adaxial surface Fruit of “seed-ejection-type,” with seeds .................................................................... 15 actively discharged by the explosive recoiling 8. Petals 5-12 mm long; fruit 13-23 mm long ... 9 8. Petals 12-21 mm long; fruit 27-52 mm long of the awn, which remains together with the ............................................................. 11 mericarp attached to the columella; mericarps 9. Calyx with glandular hairs ... 9. G. thunbergii with basal callus or prong. 9. Calyx without glandular hairs ..................... 10 1. Geranium erianthum DC., Prodr. 1: 641 10. Pedicels with retrorse, appressed, eglandular hairs; sepal mucro 0.7-1 mm long, without bris- (1824) G. pratense var. erianthum (DC.) B. tles ...................................... 10. G. retrorsum