S lTION bulletin 518 April, 1981 Aquatic Vascular Plants of New England: Part 3. Alismataceae by C. B. Hellquist and G. E. Crow BIO SCI LIBRARY NEW HAMPSHIRE AGRICULTURAL EXPERIMENT STATION UNIVERSITY OF NEW HAMPSHIRE DURHAM, NEW HAMPSHIRE 03824 S lTION bulletin 518 April, 1981 Aquatic Vascular Plants of New England: Part 3. Alismataceae by C. B. Hellquist and G. E. Crow BIO SCI LIBRARY NEW HAMPSHIRE AGRICULTURAL EXPERIMENT STATION UNIVERSITY OF NEW HAMPSHIRE DURHAM, NEW HAMPSHIRE 03824 S ?1 Hi '^^ ^l<^ ACKNOWLEDGEMENTS We wish to thank Drs. Robert K. Godfrey, Robert R. Haynes, and Arthur C. Mathieson for their helpful comments on the manuscript. Bruce Sorrie kindly supplied locality data not documented in herbaria for some of the rarer taxa occurring in southeastern Massachusetts. We are also grateful to the curators of the following herbaria for use of their collections: BOSC, BRU, CONN, CUW, GH, HNH, KIRI, MASS, MAINE, NCBS, NHA, NEBC, VT, and YU. A special thanks is extended to Pamela Bruns, who prepared the illustrations. Profirams of the New Hampshire Agricultural Experiment Station are open to all persons without regard to race, color, national origin or sex. The University of New Hampshire is an Affirmative Action/Equal Opportunity Employer. UNH LIBRARY 3 mDDD DDhlfi HbbM ABSTRACT This paper is the third in a series of reports on the aquatic and wetland flora of New England. It treats all species of the Alismataceae occurring in New England and includes keys, comments on taxonomy and nomenclature, habitat and distributional information, water chemistry data, illustrations, and dot maps. Those species regarded as rare and endangered in the New England Region or in one or more of the six New England states are also noted. One species, Echinodorus parvulus, is believed extinct in our region. KEY WORDS: Aquatic plants, New England Flora, Taxonomy, Alismataceae, Alisma, Echinodorus, Sagittaria, Water-plantain, Burhead, Arrowhead, Wapato, Duck-potato. TABLE OF CONTENTS INTRODUCTION ALISMATACEAE Alisma (Water-plantain) Key to Species Alisma gramineum Alisma plantago-aquatica Echinodorus (Burhead) Echinodorus parvulus Sagittaria (Arrowhead, Wapato, Duck-potato) Key to Species 1 2 2 2 3 3 7 7 7 7 Sagit Sagit ittaria monteuidensis 15 ittaria subulata 15 Sagittaria teres 15 Sagittaria graminea 19 Sagittaria rigida 19 ittaria latifolia 19 ittaria cuneata 20 ittaria engelmanniana 20 Sagii Sagit Sagit Literature Cited and Selected References 30 111 Aquatic Vascular Plants of New England: Part 3. Alismataceae by C. B. Hellquisti and G. E. Crow^ INTRODUCTION This is the third in a series of reports on the aquatic and wetland flora of New England. These reports are intended to aid conservation- ists, fish and game personnel, consultants, botanists, and students in the identification of aquatic plants. The coverage is strictly New Eng- land but is of value throughout the northeast. Data have been gathered from herbaria in New England and from personal field work. Chemical data presented represent samples from many waters throughout New England. The alkalinity readings are total alkalinity, expressed as milligrams per liter (mg/1) CaCO.^. Since pH and alkalin- ity vary greatly during the day, the values are only indicative of the water quality. Chloride values are given where data are available and of value. The rare and endangered plant lists referred to are those prepared for each of the six New England states by the New England Botanical Club in cooperation with the United States Fish and Wildlife Service, Office of Endangered Species, Newton Corner, MA (RI — Church and Champlin, 1978; MA — Coddington and Field, 1978; VT — Country- man, 1978; ME — Eastman, 1978; CT — Mehrhoff, 1978; NH — Storks and Crow, 1978). Taxa indicated as rare, threatened or endangered for the entire New England Region are also noted (Crow et al, 1981). We invite comments and/or criticisms on this treatment. Informa- tion on any species omitted or any known localities not documented by us will be welcomed. If anyone is interested in specific localities of any of the species indicated on the dot maps, please contact us. 'Dr. C. B. Hellquist, Department of Biology, Boston State College, 625 Huntington Avenue, Boston, MA 02115. ^Dr. G. E. Crow, Department of Botany and Plant Pathology, Nesmith Hall, Univer- sity of New Hampshire, Durham, NH 03824. ALISMATACEAE 1. Pistils in a single ring on a flat receptacle (figs. 1, 2); flowers all perfect, stamens 6. 1. Alisma 1. Pistils in a dense globose head (figs. 4E, lOD); flowers perfect or imperfect, stamens more than 6. 2. Flowers perfect; achenes plump, conspicuously ridged, not winged (fig. 3C); leaf blade never sagittate; roots not septate. 2. Echinodorus 2. Flowers imperfect, uppermost flowers mostly staminate (fig. lOA) or plants dioecious; achenes flattened, winged, not ridged (figs. lOE, 12C, 14D); leaf blade often sagittate; roots septate (fig. 4A, 6A, 9A). 3. Sagittaria Alisma (Water-plantain) Plants of shores and marshes, often submersed in water up to one meter in depth; growing from corm-like rootstalks; leaves all basal, ribbon-like, ovate or elliptical; flowers perfect, borne in a panicle; fruit an achene, borne in a circle on a flattened receptacle. Key to Species 1. Leaves submersed and ribbon-like (fig. IB) or if emersed, lanceolate to narrowly elliptic, 0.5-2.0 cm broad (fig. lA); achenes with two dorsal grooves and a central ridge (fig. IE). \. A. gramineum 1. Leaves emersed with ovate to elliptic blades (fig. 2A); occasionally submersed or floating (fig. 2B), up to 15 cm broad; achenes with single dorsal groove (fig. 2F). 2. Flowers 7.0-13.0 mm broad; sepals at anthesis 3.0-4.0 mm long; petals 3.5-6.0 mm long; fruiting heads 4.0-7.0 mm in diameter; achenes 2.2-3.0 mm long. 2a. .4. plantago-aquatica var. americanum 2. Flowers 3.0-3.5 mm broad; sepals at anthesis 2.0-2.5 mm long; petals 1.0-2.0 mm long; fruiting heads 3.0-4.0 mm broad; achenes 1.5-2.0 mm long. , . . . . 2h. A. plantago-aquatica var. parviflorum 1. Alisma gramineum Lej. Fig. 1, Map 1 Locally abundant in calcareous waters and shores of Lake Cham- plain and its tributaries. Plants are often found submersed in water to a depth of about one meter. This variable species is sometimes divided into two or three dubious varieties based primarily on vegetative fea- tures which appear to be environmentally induced. First discovered in New England in 1961 at Shelburne Bay on Lake Champlain (Coun- tryman, 1968), this species appears to be spreading rapidly throughout the lake region. Range extends from Vermont and southwest Quebec west to Wisconsin, Alberta, and British Columbia, south to South Dakota, Colorado, Nevada, and northern California. alkalinity: 47.5 mg/1 pH: 7.5 2. Alisma plantago-aquatica L. 2a. A. plantago-aquatica var. americanum Schultes and Schultes Fig. 2, Map 2 Scattered throughout New England along shores, in marshes, ponds, streams, ditches, and in shallow water. This northern taxon is treated by some authors as Alisma triviale Pursh. Range extends from Quebec west to British Columbia, south to Maryland and west Vir- ginia, Michigan, Iowa, Nebraska, New Mexico, Arizona, California, and northern Mexico. alkalinity: mean 30.5 mg/1; range 13.5-47.5 mg/1 pH: mean 7.0; range 6.5-7.5 2b. A. plantago-aquatica var. parviflorum (Pursh) Torrey Fig. 2, Map 3 Abundant along shores, in marshes, ponds, streams, ditches and in shallow water throughout New England. This more southern taxon is treated by some authors as Alisma subcordatum Raf. Most plants of var. americanum and var. parviflorum are distinct at the extremes of their geographical ranges but in New England intermediate plants occur, sometimes making identification difficult. Range extends from Maine west to New York, Ontario, Minnesota, and Nebraska, south to Florida, and Texas. alkalinity: mean 69.5 mg/1; range 11.0-290.0 mg/1 pH: mean 7.3; range 6.5-8.4 dorsal grooves central ridge D Figure 1. Alisma gramineum: \. habit of emersed plant, x '/i. B. habit of submersed plant, x '/i. C. fruiting head, x 4. D. achene, side view, x 8. E. achene, end view, x 8. dorsal groove Figure 2. Alisma plantago-aguatica var. parviflorum: A. habit of emersed plant, x Vt. B. habit of submersed plant, x V2. C. flower, X 2. D. fruiting head, x 4. E. achene, side view, X 8. F. achene, end view, x 8. var. atnericanum: G. flower, x 2, u 3 5 & 3 O C a c ^ Q. • ^ u Q OS s > S o Echinodorus (Burhead) Plants of sandy shores, often spreading by creeping shoots; leaves basal, submersed leaves lance-linear phyllodia; emersed leaves petio- late with a lanceolate blade; flowers perfect in an umbel; fruit an achene. 1. Echinodorus parvulus Engelmann Fig. 3, Map 4 A plant of sandy shores which has been reported from four sites in eastern Massachusetts, but now believed extinct in our region. The last known locality was Winter Pond, Winchester, Massachusetts. The pond has been treated with herbicides on several occasions and the species has not been reported there since 1970. The taxon is treated by some authors as Echinodorus tenellus (Mart.) Buchenau var. parvulus (Engelmann) Fassett. Populations apparently occur locally. Range extends from Massachusetts west to Ontario and Minnesota, south to central Florida and southern Texas. Rare and endangered plant lists: Massachusetts, New England Sagittaria (Arrowhead, Wapato, Duck-potato) Plants of fresh or saline waters; growing in marshes, ditches, pond shores, lakes, streams, and estuaries; emergent or submersed; growing from fibrous septate roots; spreading by stolons, some of which pro- duce tubers. Leaves extremely variable, blades sagittate or hastate to lanceolate, or bladeless, phyllodial, ribbon-like to subulate, submersed, floating or erect; flowers white, whorled in three's; bracts membran- ous; uppermost flowers usually staminate; fruit an achene. Key to Species 1. Sepals of mature flowers appressed (fig. 4D); pedicels thick and spongy (fig. 4A); leaves erect, spongy (fig. 4A); tidal mudflats. 1. S. montevidensis ssp. spongiosus 1. Sepals of mature flowers reflexed (fig. 5B); pedicels more slender, not spongy; leaves erect or lax, not spongy; mostly freshwater. 2. Leaves narrow linear phyllodia, 1-3 mm wide (fig. 5A, 6A), occa- sionally with floating ends broadening into a narrow blade (fig. 6A). 3. Plants small with linear leaves up to 30 cm long (fig. 5A); mostly estuarine. 2a. S. subulata var. subulata 8 3. Plants with long linear leaves over 30 cm (fig. 6A); in fast moving freshwater. 2b. S. suhulata var. gracillima Leaves differentiated into petiole and blade (fig. 8A) or if blade- less, then leaves terete and quill-like (fig. 7A, B), occasionally submersed leaves in populations ribbon-like (fig. 13A), usually greater than 3 mm wide. 4. Stamens with pubescent filaments (fig. 7E); leaves not sagit- tate (rarely in S. rigida). 5. Emersed and submersed leaves terete and quill-like (fig. 7A, B). 3. S. teres 5. Emersed and submersed leaves flattened (figs. 8, 9, 11, 13). 6. Flower and fruit heads pedicelled (fig. 8A); scape straight, upright (fig. 8B); leaves linear-lanceolate phyllodia (fig. 8B, C) or with narrow to broad lanceolate tapering blades; achenes rarely forming (in New England), 1.5-2.0 mm long, with small beak, 0.1-0.3 mm long. 4. S. graminea 6. Flower and fruit heads sessile or nearly so (fig. 9A); scape weak, often bent (fig. 9A); leaves erect, lanceolate (fig. 9C) to ovate (fig. 9B), occasionally with basal lobes (fig. 9D); achenes regularly formed, 2.5-4.0 mm long, with erect or arching beak 1.0-1.5 mm long (fig. 9F). 5. S. rigida 4. Stamens with glabrous filaments; leaves mostly sagittate (fig. lOA). 7. Achenes with beak horizontal (fig. lOE). 6. S. latifolia 7. Achenes with beak erect (fig. 12C, 14D). 8. Achenes 2.0-2.6 mm long, with tiny erect beak, 0.2-0.4 mm long (fig. 12C); submersed plants forming broad, ribbon- like leaves (fig. 13A) and/or floating lanceolate or sagit- tate leaves (fig. 13A, B); emersed plants usually with recurved petioles (fig. 12A). 7. S. cuneata 8. Achenes 3.6-4.5 mm long with erect or oblique beak 1.5-2.0 mm long (fig. 14D); plants always emersed, petioles ascending (fig. 14A, B). 8. S. engelmanniana Figure 3. Echinodorus parvulus: A. habit, x 1. B. nodding flower, X 3^h. C. achene, oblique, side, and end views, X 10. 10 -sepal D septate roots Figure 4. Sagittaria montevidensis ssp. spongiosus: A. habit, x V2. B., C. leaf blades, x Vz. D. flower, x 2. E. fruiting head, x 2. F. achene, x 6. 11 3 o o c ■MA lid s. s ^ 3 e >; . o^ ft c ;5 cd •^ fc. ^ ^ Q, a. ^: S es S > CO 12 D sepa Figure 5. Sagittaria subulata var. subulata: A. habit of sub- mersed plant, X V^. B. habit of emersed plant, x Vz. C. fruiting head, x 3. D. achene, x 15, 13 floati leaf Figure 6. Sagittaria subulata var. gracillima: A. habit, x V>. B. inflorescence, x V2. 14 cc Q •o c = "a tit ^ es CO ^ ~, ri :« 3