BULL. BOT. SURV. INDIA Vol. 27, NOS.1-4 : pp. 177-196, 1985 SYSTEMATICS OF THE GENUS POTENTILLA L. - (ROSACEAE JUSS.) - ITS INF'RAGENERIC CLASSIFICATION AND EVOLUTIONARY TRENDS Botanical Sum of India, Howrah ABSTRACT The genera Argentina J. Hill, Pmtaph@oi&s Duhamel, m. ilkeg* (=D&@a Rafin.1 and Dwksnea Smith are treated as congeneric synqnyms of Potantilla L. smr. strict0 ; nine sub- genera are recognised with keys to their ~denhficat~onand nomenclatural set up. The origin of the genus Potmtilla L. is discussed and evolutionary trends within the subgencra hypothesized. INTRODUCTION ARGENTINAJ. Hill vis-a-vis POTENTILLAL. Linnaeus (I753, I 754) described the genus Rydberg (1906, 1go8), followed by Hut- Potentilla L. (accredited with 22 species), and chinson (1964) treat Argentina J. Hill (as together with two other related genera, 'Lam.'), lectot~pified by the perennial Comarum L. (with I species) and Fragaria herbaceous species A. anserina (L.) Rydberg L. (with 3 spp.), attributed them to his (Potentilla anserina L.) as generically &is- class "Icosandria Polygynia". Simultaneouslv, tinct from PotentiEEa L. he assigned another related genus ~ibbaldia The discovery of primitive phenolic con- L. (with z spp.) to his class "Pentandria stituents (both elagitanins and the trihyd- Pentagynia7'. These genera are assigned roxy phenolics p~ricetin and leucodel- to-day to the family Rosaceae Juss. (1789), phinidin) in PotentiZla anserina L. (Bate- subfarn. Rosoideae, -tribe Potentilleae Juss., Smith, 1962) led Challice (1973) to visualise subtrib. Potentillinae. Rydberg (1908) and P. anserina as the most primitive member of Hutchinson (I 964) recognised 16 genera the subfam. Rosoideae in terms of chemical within the tribe Potentilleae, of which characters. Wolf (1908) also considered his species belonging to eight genera, viz. pex Anserinae Wolf (with P. anserina, Argentina J. Hill, Chamaerhodos Ledeb., amongst other taxa) as an old group from Comarum L., Duchesnea J. E. Smith, its circumpolar distribution extending way Frogaria L., pentuphylloides Duhamel nom. back to the Tertiary period. These may illeg. superfl. ( =Wpbora Rafin.), Potentilla justify segregation of Argentina J. Hill as a L. and Sibbaldia L., occur in India. While distinct genus based on A. anserina (I,.) we treat Sibbaldia L.,as generically distinct Rydberg. (Dikshit and Panigrahi, 1~81b),we reduce But in terms of comparative morphological Argentina J. Hill, Pentaphylloides Duhamel, characters such as primitive versus advanced and Duchesnea J. E. Smith as congeneric characters, Potentilla anserina L., with its with and synonymous to ~otentillaL., for herbaceous habit, rod-shaped styles, glabrous reasons as discussed hereunder : achenes coupled with its higher polyploid --- cytodemes (2n=28, 35, 42) and apomictic Date of receipt : 24.6.86. Date of accmtance : 11.8.86 nature, must be treated as an evolut~onary *Present address : Central Sericulture Institute, Kora~ut* advanced group within the genus Pot~tillt~L. Bhudan Colony, Koraput, Orissa. 178 BULLETIN OF THE BOTANICAL SURVEY OF INDIA [Vol. 27 As a member of the subgenus Cheno- entire leaflets and hairy fruits ...." and that potentilla (Focke) Juzepczuk, P. anserina "these shrubs are completely unable to cross L., has affinity with P. leuconota and with any other section ...." This group is P. coriandrifolia, amongst others, in its isolated from other taxa of Potentilla for a ~erennial herbaceous habit, im~aripinnate long time and the present distribution of leaves, rod-shaped styles and glabrous the taxa indicates that they are old well- achenes ; and with P. indica, in its perennial established types. Sojak (1969) supported herbaceous creeping habit, rod-shaped styles the idea of treating the shrubby species of and glabrous achenes. PotentiZZa as a distinct genus, because they possess alternate cotyledonary leaves, the DASIPHORARafin. vis-a-vis POTENTILLAL. primary leaves are never rosette and the stipules are ochreate, whereas, in other Schwarz (I 949), Lijve (I 954). Hutchinson species of Potentilla L., they first form roset- (1964) and Sojak (1969) considered Penta- tes and the stipules are not ochreate. phylloides Duhamel (1755) as a genus However, the genus Dasiphora Rafin., distinct from Potentilla L. and made several shares its (i) shrubby habit and absence of combinations at species rank. But the rosette leaves with Potentilla palustre (L.) genus has to be rejected as a superfluous Scop., P. salesoviana Stephan, P. sericophylla illegitimate name, in as much as Duhamel Parker and P. xylorhiza Boiss. & Hohen., (c.), (although he referred only to the but the leaflets of P. palustre and P. saleso- woody species of Potentilla L., under Penta- viam are serrate ; (ii) its entire leaflets with phylloides Duhamel) included Potentilla L. P. biflora and P. armerioides ; (iii) its hairy (not Potentilla L. p.p.) as an obligate syno- achenes with P. salesoviana, P. sericophylla, nym. (Art. 7. I I ; Art. 63. I, ICBN 1983). In P. cuneifolia, P. eriocarpa, P. curmeseta, P. the circumstances, Dasiphora Rafin. (1838) pteropoda and P. collettiana and in P. typified with D,+ria Rafin., nom. illeg., biflora, P. palustre and P. armerioides the is the next available correct name at generic achenes are glabrous ; (iv) its basic chromo- rank, if one were to consider the genus as some number x=7 (2n=14, 28) with all distinct from Potentilla L. sens. stricto. species of Potentilla L., studied to-date. Schwarz (LC.), Love 1 c.), Hutchinson The geographical distribution of various (1.c.) and Sojak (I.C.), as stated above, con- species of Dasiphora Rafin., is no more dis- sidered the shrubby Potentilla species with continuous than some other species of woolly hairy receptacles and hairy achenes Potentilla, such as P. biflora L., which as constituting a separate genus, Penta- occurs in Europe, Asia and North America. Phylloides Duhamel ( =Ihdphra Rafin.) on We, therefore, opt here to follow Wolf morphological, anatomical, chemical, cyto- (1908) in treating the Fruticosae Potentillas logical evidence and on geographical distri- as belonging to the genus Potentilla L., but bution. Liive (Z.C.), who follows Schwan segregate the species involved into two sub- (c.), observed that "taxonomically the genera, viz. subg. Dasiphora and subg. Fruticosae group doubtlessly deserves the Tricho'thalamus. rank of a separate genus, distinct from Potentilla even in its wider sense ...." and DUCHESNEAJ. E. Smith vis-a-vis that of all sections of Potentilla, the most distinct, . both morpholo~callyand anatomi- POTENTZLLAL. cally, is the group Fruticosae which includes Wolf (I go8), Bate-Smith (I g61), Kalkman pkennial shrubs, pinnately leaved with (1968) and Acharga Goswami (1972) adduce 19gsI PANIGRAHI AND DIKSHIT ; SYSTEMATICS THE GENUS PO~WTILLA L. 119 morphological, plant-chemical and genetical J. D. Hooker (1878) which conform with all evidence in support of reduction of Duches- the above characters are segregated and nea J. E. Smith (1811) as with treated as Sibbaldia L. pixit and Panigrahh PotentzUa L. (1753), because : 198I b). (i) The morphological difference between INFRAGENERIC CLASSIFICATlON OF the two genera concerns only the character Yo-rmriLLAL. WNSU STRIGTO of the torus : torus subcarnose and more or After a review of literature and critical ; less edible-Duchesnea torus not very study oi specimens we have iormulated the much enlarged and not edible-Potentilla. following classlhcation of Potentzlla L. sens. However, such a difference in the dimension s~rzcto,which recognlses g subgenera and a of the torus attained only after anthesis in number of sectlons to lnclude tne 80 lndlan Duchesnea, is merely cpantitative in nature. taxa dealt wirh, withln the systematic (ii) Chromato~raphically,Bate-Smith (1961) account of the genus : grouped Duchesnea indica with many other species of Potenrilla L., because he did I. Subg. DASIPHORA(Rafin.) Panigr. et Dik- not find any consistent differences between shit, comb. nov., et stat. nov. Dasi$hora the two genera. Rafin. in Aut. Bot. : 167. 1838 ; Rydberg (iii) Genetically, Potentilla and Duches- in N. Amer. F1. az(4). 366. 1908 ; nea belong to one compari~~m(Wolf, 1908 ; Juzepczuk, in Komarov's F1. URSS ro : Acharya Goswami, 1972) ; when Duchesnea 52. 1941 (Eng. edn. : 68. 197 I). Lectotype indica (male) was artificially crossed with sp. : Daszphora riparia Rahn. nom. illeg. Poientilla repans (female), the F, plants, [selected by Rydberg, 1908 ; = PotentlllP although remained infertile and reproduced hticosa L. ; = Dasiphora fruticosa (L.) only vegetatively, had very luxurious Rydberg]. growth and flowered extensively. In view of such evidence, we treat 2. Subg. TRICHOTHALAMUS(Lehm.) Reich., Duchesnea Smith as a subgenus of Potm- Consp. Rep. Veget. : 167. 1828. Tricho- till22 L. thalamus [Spreng. Anleit. ed. 2, 2 : 864. 18181 Lehm. in Nova Acta Acad. Leap.- Carol. 10 : 585. 1821. Type species : SIBBALDIAL. vis-a-vis POTENTILLAL. Trichothalamus lignosus (Wllld. ex Linnaeus (1753, 1754). Wolf (~gd),Ryd- Schlecht.) Lehm. ( = Potentilla lignosa berg (1g08), Juzepczuk (I 94 I) and Hutchin- Willd. ex Schlecht.). son (1964) treat Sibbaldia L., as generically Potentilla L. subg. Lasiocarpa DiHit et distinct from Potentilla L. and differentiate Panigrahi in Journ. Sc. Club 33-34 : 39. them on the number of stamens : 4, 5 or 10 1983, Type species : P. salesoviana starnens4ibbaldia whereas 2e30 st amens- Stephan. Poten~iNaL. Except the number of stamens, no other consistent difference can be discern- 3 Subg.