Uniuemj} of ^tliii ^ >/ •i i 60. I -^ I 5 3 X ^N BULLETIN 515 January, 1980 itic Vascular Plants of New England: Part 1. Zoster aceae, Potamogetonaceae, Zanniehelliaceae, Najadaceae by C. B. Hellquist and G. E. Crow NEW HAMPSHIRE AGRICULTURAL EXPERIMENT STATION UNIVERSITY OF NEW HAMPSHIRE DURHAM, NEW HAMPSHIRE Uni>7ersUy of Msv/ Ha-r-^-ir- Library ACKNOWLEDGEMENTS We wish to thank Drs. Robert R. Haynes, Eugene C. Ogden, Arthur C. Mathieson and Edward G. Voss for their helpful comments on the manuscript. We are also grateful to the " " ' " for use of their collections: , MASS, MAINE, NCBS , NHA, . were prepared by C. Barre Hellquist . Artnur u. watnieson ana cuwara v comments on the manuscript. We ; curators of the following herbaria f( BOSC, BRU, CONN, CUW, GH, HNH , KIRI , NEBC, VT, YU. Illustrations i Programs 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. ABSTRACT This paper is the first in a series of reports on the aquatic and wetland flora of New England. It treats all species of the Zosteraceae, Potamogetonaceae , Zannichelliaceae and Najadaceae occurring in New England and includes keys, comments on taxonomy and nomenclature, habitat and distributional information, water chemistry data, illustrations and dot maps. Several species are regarded as rare and endangered in one or more of the six New England states and are so noted. One taxon, Potamogeton f iliformis var. occidentalis (previously reported as P_^ vaginatus) is newly reported for New England. KEY WORDS: Aquatic Plants, New England Flora, Taxonomy, Potamogetonaceae, Zosteraceae, Zannichelliaceae, Najadaceae, Potamogeton, Ruppia, Zostera, Zannichellia, Najas , Pondweed, Eelgrass, Widgeon-grass, Horned Pondweed, Naiad. Table of Contents INTRODUCTION 1 FAMILY KEY 2 ZOSTERACEAE 3 Zosteca 3 Zoster a mar ina 3 Selected References 3 POTAMOGETONACEAE 3 Potamogeton 5 Key to Species 5 Potamogeton robbinsii 12 Potamogeton pectinatus 12 Potamogeton f ilif ormis 12 Potamogeton bicupulatus 17 Potamogeton spir illus 17 Potamogeton diver sifol ius 17 Potamogeton epihydrus 21 Potamogeton conf ervoides 21 Potamogeton zoster if ormis 21 Potamogeton hilli i 26 Potamogeton foliosus 26 Potamogeton f r iesi i 26 Potamogeton str ictif ol ius 26 Potamogeton obtusif olius 31 Potamogeton pusillus 31 Potamogeton vaseyi 36 Potamogeton lateralis 36 11 Potamogeton natans 36 Potamogeton oakesianus 40 Potamogeton cr ispus 40 Potamogeton ampl if ol ius 40 Potamogeton pulcher 40 Potamogeton nodosus 40 Potamogeton alpinus 46 Potamogeton gr amineus 46 Potamogeton illinoensis 46 Potamogeton praelongus 52 Potamoteton r ichardsoni i 52 Potamogeton per f ol iatus 52 Selected References 56 Ruppia 57 Ruppia mar itima 57 Selected References 59 ZANNICHELLIACEAE 59 Zannichell ia 59 Zannichellia palustr is 59 NAJADACEAE 61 Najas 61 Key to Species 61 Najas guadalupensis 61 Najas f lexilis 61 Najas gracillima 64 Najas minor 64 Selected References 64 LITERATURE CITED 67 111 AQUATIC VASCULAR PLANTS OF NEW ENGLAND: Part 1. Zosteraceae, Potamogetonaceae , Zannichelliaceae , Najadaceae by C. B. Hellquist and G. E. Crow INTRODUCTION This is the first in a series of reports on the aquatic and wetland flora of New England. Eventually all of the reports will be combined into a manual of aquatic and wetland plants of New England. By releasing these preliminary reports on families or groups of families we hope for constant updating through field work until the final manual is prepared. A treatment of the aquatic and wetland plants of the New England region has long been needed. The manual is being prepared to aid conservationists, fish and game personnel, consultants, botanists and students in the identification of aquatic plants. The coverage is strictly New England but is of value throughout the northeast. Data have been gathered from herbaria in New England and from personal field work. Chemical data presented have been gathered from many waters throughout New England. The alkalinity readings are total alkalinity, expressed as milligrams per liter (mg/1) CaC03. Since pH and alkalinity 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 (Church and Champlin, 1978; Coddington and Field, 1978; Countryman, 1978; Eastman, 1978; Mehrhoff, 1978; Storks and Crow, 1978) . We invite comments and/or criticisms on this report. Information 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, University of New Hampshire, Durham, NH 03824. - 2 - FAMILY KEY Leaves alternate Plants marine or of estuaries; leaves up to 2 m long, all submersed; flowers imperfect; inflorescence an elongate, flattened spike, surrounded by a sheathing leaf-like spathe at maturity (fig. 1A,B) . Zosteraceae 2. Plants freshwater or estuarine; leaves much less than 2 m long, submersed and/or floating; flowers perfect (2 per spike in Ruppia) ; inflorescence a cylindric spike, enveloped by stipule (Potamogeton) or sheathing leaf base (Ruppia) during development, becoming exserted at maturity (fig. 9A, 37A) . Potamogetonaceae Leaves opposite, occasionally appearing whorled Plants perennial, rhizomes common (fig. 38A) ; leaves entire, without broadened bases; flowers and fruits borne on short stalks; fruits bilaterally symmetrical, usually dentate (occasionally minutely spinulose) on one side (fig. 38B) . Zannichelliaceae 3. Plants annual; rhizome lacking (fig. 39A) ; leaves mostly serrate, with broadened, sheathing bases (fig. 38B, C) ; flowers and fruits sessile; fruits radially symmetrical, smooth. Na j adaceae - 3 - ZOSTERACEAE Zostera (Eelgrass) Submersed plants of estuaries and sea water along the coast; arising from rhizomes; flowers unisexual, borne in rows on the upper side of a leaf-like spathe. 1. Zostera marina L. Fig. 1, Map 1 Common in estuaries, bays and along the open coast. The taxon in New England is treated as var . stenophylla Aschers. and Graebn. by Fernald (1950). Range extends from Greenland to Florida and along the west coast of the United States and Canada. Selected References Setchell, W. A. 1929. Morphological and phenological notes on Zostera marina L. Univ. Calif. Publ. Bot. 14: 389-452. Setchell, W. A. 1933. A preliminary survey of the species of Zostera. Proc. Natl. Acad. U.S.A. 19: 810-817. POTAMOGETONACEAE Flowers several to many, exerted above stipule at anthesis, stamens 4; fruit sessile on a cylindric spike (fig. 3A) , sometimes appearing capitate; floating leaves (fig. 9A) present or absent; stipules free from leaf blade (fig. 18B) or if fused with leaf blade, then the tip free (fig. 3B) . 1 . Potamogeton Flowers 2, enclosed in leaf sheath at anthesis, stamens 2; fruit long-stalked (fig. 37A) ; floating leaves absent, stipules fused with leaf blades, free tip lacking (fig. 37B) . 2 . Ruppia - 4 - c •H 1-1 m a (o| m u s 0) ^ CO o SI 0) u x> (0 0) • M CQ 3 1 U>< M • • 03 C -H U (0 . £ -^J •r-l (0 D Vj i-i 0) M-l 4J 03 O « N u - 5 - Potamogeton (Pondweed) Plants of fresh or saline water; growing from rhizomes or winter buds; leaves alternate, variable, with a characteristic mid-vein; floating leaves present in many species; flowers borne in spikes which may or may not rise above the water's surface; fruits drupaceous. Many hybrids occur, particularly between the broad-leaved species. Key to Species Plants with stipules adnate to leaf sheaths (figs. 2D, 3B , 6B) . 2. Stipules adnate to leaf for 10 mm or more (figs. 2D, 3B) ; floating leaves absent; fruit usually without a lateral keel, embryo indistinctly coiled (figs. 3E, 5C) . 3. Leaves 3-8 mm wide, stiffish, 2-ranked, lobed at junction with stipule (fig. 2D); leaves usually with fine serrations, seen under magnification (fig. 2C) . 1 . P_^ robbinsii 3. Leaves 0.2-2.0 mm wide, lax, not distinctly 2-ranked, nor lobed at base; leaves without serrations. 4. Leaves acute (fig. 3D), apiculate on young plants (fig. 3C) ; fruits beaked (fig. 3E) . 2 . P_^ pectinatus 4. Leaves blunt (fig. 5H) , obtuse (fig. 4E) , notched (figs. 4C,D, 5G) or rarely apiculate (fig. 4F) . 5. Plants tall, 3-10 dm long; stipules on lower portion of stem loose and inflated (fig. 43), disintegrating early (fig. 4A) ; leaves 0.5-2.0 mm wide 3 . P^ f iliformis var . occidental is 5. Plants short, 1-3 dm long; stipules on the lower portion of the stem usually tightly clasping, not disintegrating (figs. 5D,E); leaves 0.2-0.8 mm wide 4 . P_^ f iliformis var . alpinus 2. Stipules adnate to leaf for a distance of less than 10.0 mm; floating leaves absent or present; fruit with obvious lateral keel and embryo distinctly coiled (figs. 6C, 7C,D, 8D) . - 6 - 6. Submersed leaves 0.1-0.6 mm wide, tapering to a long point (fig. 6B) , lacunae not abundant; middle stem leaves 190-500 times as long as broad; free portion of stipule 3 or more times as long as the fused portion; floating leaves (fig. 6A) , 3-7-veined, the apicies acute. 5. Pjj_ bicupulatus 6. Submersed leaves 0.5-2.0 mm wide, not long tapering; lacunae abundant (fig. 8C) ; middle stem leaves less than 190 times as long as broad; free portion of stipule not more than twice as long as fused portion; floating leaves 5-15-veined, the apicies acute or obtuse (figs. 7A, 8A) . 7. Tips of submersed leaves obtuse (fig. 7E) ; fruit 1.3-2.2 mm wide, lateral keels scarcely developed (fig. 7D) , or rarely well developed (fig. 7C) , beak lacking. 6. Pj^ spirillus 7. Tips of submersed leaves acute (fig. 8B) ; fruit 1.0-1.5 mm wide, lateral keels well developed, minute beak present (fig. 8D) . 7. Pjj^ diversifolius 1. Plants with stipules completely free (figs. 14C, 15D, 18B) . 8. Submersed leaves linear, with parallel margins, 0.1-10.0 mm wide (figs. 9A, IIC, 12A) . 9. Lacunae prominent in submersed leaves (figs. 9D, lOB) , 2-10 mm wide; floating leaves often present; fruit with keel 0.2-1.2 mm broad. 8. Pj^ epihydrus 9. Lacunae not prominent in submersed leaves, (except in some specimens of P^^ pusillus var. tenuissimus) , 0.1-3.2 mm wide; fruit with keel less than 0.2 mm broad. 10. Floating leaves absent. 11. Rhizome long and creeping (fig. IIA) ; peduncle 15-24 cm long (fig. HA); leaves thread-like (fig. 11A,C) , 0.1-0.5 mm wide. 9. Pj^ confervoides 11. Rhizome short or lacking; peduncle 0.3-10 cm long, often curved (figs. 13A, 14A) ; leaves usually not thread-like (figs. 12-19) [except in P^ pusillus var. gemjniparus (fig. 20)], 0.1-3.2 mm wide. 12. Nodal glands absent (fig. 14C) . 13. Leaves 15-25-veined (fig. 12B) , - 7 - greater than 2.0 mm wide; fruits 3-3.5 mm wide (fig. 12F) . 10. P_^ zoster if ormis 13. Leaves 3-5-veined (fig. 13F, 15C) , usually less than 2.0 ram wide; fruits less than 3.0 mm wide. 14. Leaves usually bristle-tipped (figs. 13B,F); occasionally apiculate (fig. 13D) to blunt (fig. 13E) , 3-veined, 1-2.2 (-4) mm wide, peduncles slightly clavate, recurved, axillary or terminal, 0.6-1.35 cm long; fruits 3-keeled (fig. 13G) , 3-4 mm long. 11. P^ hillii 14. Leaves acute (fig. 14D) , 3 (-5)-veined, 0.3-1.5 (2.7) mm wide; peduncles clavate, usually recurved 0.3-1.1 (-3.7) cm long, axillary; fruits 1-keeled (fig. 14B) , up to 2.7 mm long, usually 1.8-2.3 mm. 12. P_;^ foliosus 12. Nodal glands present (figs. 15D, 16G, 18B) . 15. Stipules coarsely fibrous (figs. 15D, 16G) , often whitish. 16. Leaf tips rounded or apiculate (fig. 15C) ; leaves 5-7 (-9)-veined (fig. 15C) ; winter buds with inner leaves at a right angle to outer leaves. 13 . P_^ f r iesii 16. Leaf tips usually bristled (fig. 168); leaves acute (figs. 16C,D) or rarely obtuse to apiculate (fig. 16E) , 3-5 (-7) -veined; winter buds flattened with inner and outer leaves in the same plane. 14. P_j_ str ictif olius 15. Stipules not fibrous, usually delicate (fig. 183), greenish, brown, or white. 17. Leaves 0.2-3.5 mm wide, apex blunt (fig. 18D) to acute (fig. 19F) , 3-5-veined; peduncles - 8 - 0.35-8.0 cm long. 18. Leaves 1.0-3.5 mm wide, often rufescent (reddish- brown) ; apex rounded (fig. 17C) or slightly apiculate; fruits with dorsal keel or ridge (fig. 17B) . 15. P^ obtusifolius 18. Leaves 0.2-2.5 mm wide, usually green; apex obtuse (fig. 19B) , apiculate (fig. 19D) or acute (fig. 19F) , fruits with a rounded dorsal surface, (figs. 18F, 191) . 19. Leaves with up to 2 rows of lacunae along both sides of the midrib (fig. 19F) , apex acute (fig. 18E) , rarely apiculate; stipules mostly connate (united, surrounding stem) peduncles mostly terminal, 1.0-6.2 cm long, 1-3 per plant; inflorescence usually of 2-4 distinct, inter- rupted whorls (fig. 18A) . 16. Pj^ pusillus var . pusillus 19. Leaves with up to 5 rows of lacunae on both sides of midrib, apex obtuse (fig. 19B) to acute (fig. 19F) ; stipules mostly convolute (rolled); peduncles axillary or terminal, 0.5-4.6 (-6.6) cm long, more than 3 per plant; inflorescence crowded (fig. 19A) . 17. Pj^ pusillus var . tenuissimus 17. Leaves 0.2-0.7 mm wide, apex acute (fig. 20C) , leaves 1-veined; peduncles 1.0-3.5 cm long. 18. P_j_ pusillus - 9 - 10. Floating leaves present on at least some plants in population (Figs. 2lA, 22E). 20. Floating leaves 0.6-1.5 cm long, 5-9-veined: submersed leaves thin and transparent; fruit less than 2.5 cm long. 21. Submersed leaves 0.1-1.0 mm wide; floating leaves 5-9-veined, often obovate (fig. 21A) ; winter buds common (fig. 21E); fruit compressed with distinct dorsal keel and recurved beak (fig. 21B) ; no fruit on plants with only submersed leaves. 19 . P_^ vaseyi 21. Submersed leaves 0.4-1.0 mm wide; floating leaves 5-7-veined, usually spatulate (fig. 22E) ; winter buds usually absent; fruit slightly compressed with strongly rounded back (fig. 22D) , (fruit very similar to P . pusillus) ; winter buds occasionally found; fruit only on plants with submersed leaves, but plants with floating leaves may bear flowers. 20. P_^ lateralis 20. Floating leaves, 1.5-12.0 cm long, 7-37-veined; submersed leaves thick and phyllodia-like (or stem-like) (fig. 23A) ; fruit 2.5-3.5 cm long. 22. Submersed (phyllodial) leaves 0.8-2.0 mm wide; floating leaf blades 2.5-6.0 cm wide, 13-37 veins, usually heart-shaped at base (fig. 23A) , (floating leaves in strong currents lack heart-shaped bases); petiole pale at summit; fruits mostly 3.5-5.0 mm long, keels obscure (fig. 23B) . 21. P_^ natans 22. Submersed (phyllodial) leaves 0.3-1.0 mm wide; floating leaf blades 1.0-3.0 cm wide, rounded or wedge-shaped at base (fig. 24A) ; petiole not pale at summit; fruits mostly 2.5-3.5 mm long, keels prominent (fig. 24B) . 22 . P_^ oakesianus Submersed leaves non-linear, without parallel margins (figs. 26A, 30A) , 10.0 mm-75.0 mm wide. 23. Stem flattened; margins of leaves conspicuously toothed (fig. 258); stipules slightly fused to base of leaf; fruit beak 2-3 mm long (fig. 25C); winter - 10 - buds common and extremely hard. 23 . P_j_ crispus 23. Stem round in cross-section; leaves not toothed; fruit beak 1.0 mm long or less; winter buds rare, soft. 24. Submersed leaves sessile (but not clasping) (figs. 29A, 30A) , or petioled (figs. 26A, 27A, 28A) ; floating leaves absent or present. 25. Submersed leaves 27-37-veined (fig. 26A) , distinctly arced (fig. 26A) . 24 . P^ amplifolius 25. Submersed leaves less than 27-veined, not arced. 26. Stems conspicuously black-spotted; submersed leaves curly or wavy along the margin (fig. 27A) ; floating leaves 21-35-veined. 25. P_j_ pulcher 26. Stems not conspicuously black-spotted; submersed leaves not curly or wavy along the margin; floating leaves 2-29-veined . 27. Submersed leaves with petiole 2-13 cm in length (fig. 28A) ; fruit length 3.5-4.3 mm. 26 . P_^ nodosus 27. Submersed leaves sessile (figs. 29A, 30A, 31, 32, 33A) (occasional leaf petiolate to 4.0 cm long in P. illinoensis) ; fruit length less than 3.5 mm. 28. Submersed leaves 7-veined (often with up to six additional faint veins) with apex obtuse (figs. 29B,C) or acute (figs. 29D,E); reticulate portion along midrib, reddish color on drying; stipules blunt (fig. 29A) ; fruit plump, tawny-olive, pedicelled (figs. 29G,F). 27. P_^ alpinus 28. Submersed leaves 3-17-veined (all prominent) with apex acute or with an awl-like tip (figs. 31, 33A) , lacking obvious reticulate portion along the midrib, not reddish color on - 11 - drying; stipules acute; fruit laterally compressed, reddish- brown, not pedicelled. 29 Stem commonly branched (fig. 30A) ; submersed leaves always sessile , 1.5-4.5 (-13) cm long. blades (3-) 5-9 (-ll)-veined. 28, P. grammeus 29. Stem rarely or once branched; submersed leaves sessile (ocassional leaf petiolate up to 4,0 cm long), blades 5.0-20.0 cm long, (7-) 9-19-veined (fig. 33A) . 29. P^ illinoensis 24. Submersed leaves clasping stem (figs. 33A, 34A, 35A) ; floating leaves absent. 30. Rhizomes spotted with rusty red; leaves ovate-oblong, (5-) 10-20 (-25) cm long (fig. 34A) , apex boat-shaped (curved upward) (fig. 34C) , and splitting when pressed (fig. 34D) ; stipules usually persistent and conspicuous. 30. P^ praelongus 30. Rhizomes unspotted; leaves roundish-ovate (fig. 36E) , orbicular (Fig. 36G) to lanceolate (Fig. 36H) , 1-10 cm long, apex flat; stipules inconspicuous (fig. 36A) or disintegrating into fibers (fig. 35A) . 31. Leaves ovate-lanceolate (fig. 35C) to narrowly-lanceolate, 3-10 cm long, with 7-33 coarse veins; stipules coarse, disintegrating to persistent white fibers, even on the lower portion of the stem (fig. 35A) . 31 . P^ r ichardsonii 31. Leaves orbicular (fig. 36C) to ovate (fig. 36G) , becoming lanceoclate in soft water (fig. 36H) , 1.0-6.0 cm long, 0.5-2.0 cm wide, with 7-17 delicate veins; stipules disintegrating and absent on the lower portions of the stem. 32. P. per foliatus - 12 - 1. Potamogeton robbinsii Oakes Fig. 2, Map 2 Abundant in deep water and slow streams. The type locality is Cherry Pond, Lancaster, New Hampshire. This species is especially distinctive among North American Potamogetons . It is not closely related to any other species and its pollen has a unique surface pattern. It is usually found at greater depths than most pondweeds, and then, sterile. Plants approaching the surface often flower, but seldom set fruit. Only three populations among those documented in New England herbaria were represented by material with mature fruit. Leaves normally have very minutely toothed margins (use strong lens) . P_^ robbinsii forma cultellatus Fassett lacks toothed margins and is uncommon in New England. Range extends from Labrador west to British Columbia, south to New Jersey, Indiana, Alabama, Utah, and California; most abundant in the northeast. alkalinity: mean, 26.1 mg/1; range 3.0-103.5 mg/1 pH: mean 7.2; range 6.3-8.9 2. Potamogeton pectinatus L. Fig. 3, Map 3 Locally abundant in scattered locations along the coast and inland in calcareous lakes, rivers and shallow streams of western New England, uncommon elsewhere. Although this species is the major pondweed for duck food (Metcalf, 1931), its food value in New England is low due to its limited occurrence. Range extends throughout the United States and Canada. Rare and endangered plant list: New Hampshire alkalinity: mean 91.7 mg/1; range 27.5-231.5 mg/1 pH: mean 8.0; range 6.5-10.7 chloride: mean 408.2 mg/1; range 3.3-4095.0 mg/1 3. Potamogeton f iliformis Pers. var. occidentalis (Robbins) Morong Fig. 4, Map 4 Known only from two locations in northern Aroostook County, Maine. The nomenclature used follows Cronquist et al. (1977). This robust variety is characterized by inflated stipular sheaths in young plants which are similar to those of P. vaginatus Turcz. These sheaths deteriorate early, hence are lacking on older plants. This was previously reported as P. vaginatus by Hellquist (1977) . Range extends from Nova Scotia west through southern Canada, south to Maine, Michigan, Texas, Colorado, New Mexico, and Arizona. alkalinity: mean 103.5 mg/1 pH: mean 7.3 4. Potamogeton f iliformis Pers. var. alpinus (Blytt) Aschers. and Graebner Fig. 5, Map 5 Locally abundant in shallow calcareous waters and marl springs of Aroostook County, Maine; uncommon at scattered locations in northern New Hampshire and Vermont. This taxon is - 13 - CQ Q 14-1 m • dj 4J r-H (0 o s: c o •H • 4J o 1-1 -H D W Oi C •r-t -H X> u 0 l-l •H u C 4-1 0 • 4-) 0) 0 q; w ai U (Q 0 D ia e 4-1 (0 (0 U-l 4J e (0 0 e (u IX ■H nH - 14 - tn D 4-1 c •H 4-> U • (U Cb c ns O 0) en o e (0 4J o - 15 - "i^. ^ ^X^ .y (0 ■H e >-i w o -rH y-i --1 ■H n: I— 1 -U • -rH c ■^ U-l 0 -Dl a c ■rH m o u s: -u u (D o o 6 (0 o CO •H iH (0 4J c •o •H o o o 0) c (TJ • c (0 w Q> ■H U e D u CTi Ol ■H <4-l fc •H iH •M M-l 0) o (0 (0 (0 b I C • CJ O 4J -P -H en | o e (0 o (0 gr^TT",' 1 '7-^^ J £_ < ■PUS •H 1 1 XI Q bj (0 •• x: w • 3 (0 c • • (1) -H OQ -U I-H a •H D iH 3 tt m U -H • U-l 4-) • 4J 01 1-1 c 03 m • > i-H • QJ IT) DjCJ -tJ u nj 0) -H c >- e TJ -U 03 D U Q) C as CTi 0 > ns •H M-l (0 iH h -H 0) Q4'0 rH M c •H 1 fO 14-1 TJ tJ nj OJ c 0 > W 0 1-1 m 0) 4J J3 -< (0<4-l O 0) U-l >-l -H -o • 3 W C Q D> l-i (0 •H (1) tl4 > • •H (U u-l < -o M (0 (0 (U ja r-( c o U-l 4J u-l O JJ u o • O (X CO Cb - 21 - 8. Potamogeton epihydrus Raf. Figs. 9, 10, Maps 9, 10 Abundant throughout New England in acid and alkaline waters. Two varieties are recognized: the ubiquitous var. ramosus [var. nuttallii of Fernald, (1950)] and the uncommon variety epihydrus from alkaline waters of western and northern New England. Only the extremes of these two varieties are easy to distinguish. Range extends from Newfoundland and Labrador west to southern Manitoba, and southern Alaska, south to western North Carolina, Tennessee, northern Mississippi, Colorado, and California; most abundant in the northeast. Leaves 5-10 mm broad, 7-13-veined; fruit 3-4.5 mm long, 3-3.6 mm broad. var. epihydrus Leaves 1-8 mm broad, (3) 5-7-veined; fruit 2.5-3.5 mm long, 2-3 mm broad. var. ramosus (Peck) House variety ramosus alkalinity: mean 20.1 mg/1; range 2.0-245.0 mg/1 pH : mean 6.8; range 5.0-9.5 variety epihydrus alkalinity: mean 62.5 mg/1; range 9.0-120.0 mg/1 pH: mean 7.5; range 6.8-8.6 9. Potamogeton conf ervoides Reichenb. Fig. 11, Map 11 Found in acid waters of New England along the coastal plain and in high elevation lakes and ponds. This species is found in waters of the greatest acidity in New England. The pH may be as low as 5.0 and the alkalinity can approach 0.0 mg/1. Potamogeton conf ervoides may be overlooked if not in fruit as it blends in with Eleochar is acicular is , E. robbinsii and Scirpus subterminalis , with which it is often associated. Range extends from Newfoundland west to the Upper Peninsula of Michigan and eastern Wisconsin, south to southern New Jersey, Pennsylvania, and North Carolina. Rare and endangered plant list: Maine, Vermont, Connecticut alkalinity: mean 3.6 mg/1; range 0.5-7.0 mg/1 pH : mean 6.3; range 5.3-6.8 10. Potamogeton zoster if ormis Fernald Fig. 12, Map 12 Scattered throughout New England with population concentrations in regions of higher alkalinity, particularly along the western border. Range extends from the Gaspe Peninsula of Quebec west to Manitoba, south to northern Virginia, southern Ohio and Nebraska; a minor range extension occurs from western Montana to British Columbia; south to Oregon; isolated populations in northern Alberta and northern California. - 22 U) o u TD W >. D SZ u •r-l t5 • a >, CTl 0) £ •r^l a C a (U O (D tj) 1-1 - 23 - a. o Ul D U T3 >i m x; D ■H CO a o QJ e fOl ? ^1 u D • • 4-1 m 3 W o e nj • (0 (0 iH > c o H -p o ITS • 0 -P rH XI m • x: Q - 24 - , — j- V-j"' , -r ^i "1- Cf" (0 0) •a -H o > • c r-l O a c (0 o 0) cn| o e (0 ■u o (I4 m n <-\ W iH 0) TJ (U •H ki 0 3 > tJ> w.| ■H 0) Eb >4-l| c 0 0 c o o e (0 o 04 u • • - 25 ti, J-7-, "A -^ r^' >•••> ; N '■>.r-' "X.,.^-*-^ r-- 1 ^^ — 'iJ ,• ^^^ •H u o •H 0) • 4J (N W •-{ o N Qj (0 C S O 4J (U cn| o e m -p o 4J w •H a XI ■H (0 4J x: y-i m -.: ^- — y ..-''-, .-..X- --,w.. - [ -i H f L._r --J •n .^.^^ -'^^ '^ s V^I r^^ > -< CO c fH o 4-) a (u| (0 Oi s o e fO 4J o Oj - 28 - CQ x: nJ 0 (0 u D 3 W D^ 0| H •r^ X, rH O U-l c o 0) o E nj o m (0 x> o - 29 - - 30 - o >4-l (0 m c s o 4J 0) cn| o o ^^=-kj^ - 31 - this species follows Haynes (1974) who does not recognize inf raspecif ic taxa due to the range of variability observed both between and within populations. Hybrids between this species and P. zoster if ormis may be called P_^ X long il igulatus Fernald (Hayries and Williams, 1975). Range extends from eastern Quebec to the Northwest Territories, south to northwest Connecticut, New York, Indiana, Minnesota, Nebraska, Wyoming and northern Utah; most abundant in the Great Lakes region. Rare and endangered plant lists: Massachusetts, Connecticut alkalinity: mean 76.1 rag/1; range 55.0-109.0 mg/1 pH: mean 7.5; range 7.0-8.4 alkalinity: mean 49.1 mg/1; range pH : mean 7.4; range 6.7-8.2 16. Potamogeton pusillus L. var . pusillus Fig. 18, Map 18 Uncommon in northeastern Maine, abundant in western New England in alkaline waters. Includes both var. pusillus and var. minor of Fernald (1950). Range extends throughout North America from Newfoundland and Labrador west to Northwest Territories and Alaska, south to Mexico and Guatemala. alkalinity: mean 64,1 mg/1; range 25.0-114.5 mg/1 pH : mean 8.1; range 7.3-10.2 17. Potamogeton pusillus L. var. tenuissimus Mert. and Koch Fig. 19, Map 19 Extremely common in acid and alkaline waters throughout New England; occasionally in brackish water along the coast. Includes all varieties of P^ berchtoldii Fieber (Haynes, 1974) as treated by Fernald (1950) . Range extends from Newfoundland to Alaska, south to northern Florida, Louisiana, and California; most abundant in the northeast. alkalinity: mean 32.4 mg/1; range 2.5-179.0 mg/1 pH : mean 7.1; range 5.6-10.2 18. Potamogeton pusillus L. var. gemmipar us Robbins Fig. 20, Map 20 Uncommon in acid waters of eastern New England. Treated by Fernald (1932) as P_^ geramiparus (Robbins) Morong; however, Haynes (1974) recognized it as a variety of P_^ pusillus . This - 32 - w a • 4J i-H O a C (0 o S -P cu o (0 o CQ J3 -P m (0 r~ w rH 3 •H • 0) .-H 4J )-. O •H CD D IW D CT>-i-l u -H M H^ IJLj D JJ J3 • O O C o • -p 0) 0) w en (0 O XI e (0 14-1 -p' ro o Q) a< •-i - 33 - f-i-. ,—- u.^>- ■-1 .„---'■ -A >- s^' x I* v./ — "( V «u X-... ^*^ A ^» A. ,-r. -,V^-, .-' T.^ ) U) D iH iH •H Ul U] 3 3 iH • a r-{ 00 -H .-H C tn o 3 a-p D. ra (U S en • O t-i e nj (0 > 4-1 o 04 < (0 a •H 4J • • 01 tM 3 m i-H 0) rH tH •H 01 3 • a u -a J • O a> • u c 00 ns 1 .-1 > • 1 0) u CQ ~^/ CO (CJ r^/- 3 3 XI Ms< ai'— 1 ^4. < -H rH IW \ Cl4 •r-l (0 CO 0) 3 rH a c . o PQ • 4-1 4-> (U •H C7I 3 O • Vj e 4J <4-l (0 •H 4-) X} o (0 • 04 SZ fc, I - 34 - i X 4:^::x: i CO 4-) 4-) 3 •H •H e D D •H U U w IW U-l M •H 3 • • C bn M •H ■ • 03 (0 -H > -P 0) iJ" ■~^" 1 <^' )-- 1 — ,L.... /^x >/ 'f T-x- ^3i II -^' -< to 3 iH fH (0 ■H 3 W Vj D m • a D. O -rHl CM C e O E Qj-4-> 0 (0 0) o- s d o • e u nj (0 -P > o (l4 ^ • * • 'O O U 3 CM ro ja > (U J-i to u 3 3 0) cr>-i 4J •H r-K c fa -H ■H w » 3 oX c • o OQ < ^J N & ^ o • e -i-i <■ (0 -H 4-1 XI o OJ cu x: 36 - narrow-leaved variety, which rarely sets fruit, was originally described from Uxbridge, Massachusetts. Range extends out of New England to one locality in southeastern Quebec. Rare and endangered plant lists: New Hampshire, Connecticut alkalinity: mean 9.4 mg/1; range 2.5-17.0 pH : mean 6.7; range 6.3-7.1 19. Potamogeton vaseyi Robbins Figi 21, Map 21 Uncommon at widely scattered locations in moderately alkaline waters throughout New England. Plants without floating leaves are easily confused with P_^ pusill us var. gemmipar us . Range extends from New Brunswick west to Wisconsin, south to Connecticut, Pennsylvania, northeastern Ohio, Michigan, northern Illinois, Wisconsin, and Minnesota. Rare and endangered Connecticut plant lists Maine, New Hampshire, alkalinity: mean 24.5 mg/1; range 7.0-55.0 mg/1 pH : mean 7.2; range 6.7-7.6 20 Potamogeton lateral is Morong Fig. 22, Map 22 Ext local ities. been docume interest s vaseyi . Ho leaves of Connecticut have been P . pusill Hampshire Connecticut and easter its similar reme 0 nted ince weve P pop iden us and w n M ity ly r a nly t sine the r , the _ 1 ulatio tif ied var . Vermo idely inneso to P. re, he N e 1 pla f r u ater known in New Engla ew Hampshire and Vermon 880. The Vermont po mixed with and the spa distinctive . in various nts grow its differ alls are P. lateralis var sig ns documented as tenuissimus nt south to Massachusetts scattered locations in New ta. This species may be o vaseyi . nd from five t locations have pulation is of the similar P_^ tulate floating The Danbury, herbaria which moides Eames are from Range extends from New and northeastern York, Michigan, verlooked due to Rare and endangered plant lists; Massachusetts, Connecticut New Hampshire, Vermont, alkalinity: mean 34.5 mg/1; range 13.5-55.0 mg/1 pH : mean 6.6; range 6.4-6.7 21 Potamogeton natans L. Fig. 23, Map 2 3 Extremely common in New England. Range extends from Newfoundland to Alaska, south to New Jersey, northern Indiana, Nebraska, Colorado, Arizona, and southern California; reported from one location in North Carolina where it evidently was a short-lived introduction. alkalinity: mean 36.7 mg/1; range 2.5-245.0 mg/1 pH : mean 7.1; range 5.0-9.8 - 37 - •H > w (0 > 1— 1 c CN o ■u a ■H (0 XI Q) (C f— 1 x: iw w o a •r-( • • -P i-H < W CM C ^ O ITS 0) -nH 0) J-l •• JJ r— 1 D -H u cn > O •H 0) a • Cl. CO ac (0 1 > fa Q < c 1 • o U t3 4-> D 0) XI cn O • u e J-) -P D C O U -H a< y-i s - 38 - '-L-> ./" ,-J~-^-A ! J r^~-' ^- -NV A ^2> 1 A. ^-^ — t •l I >-■ — _ r-e- .^^^ .-^'^-' "-< ra nj (U • (0 OJ r-l CM c &1 o Z (1) cm o (0 o CM .. (0 C CO 0 o -'' "■A' ...i" J># 1 A. ■#., /. a A \...^-^- I .•\. A J /" -^' -t>» ;»•• • (^ CN • • CO 4-) 0) 3 c 1-1 a' (0 D c i-H tji ■rH a r^ e Cu (0 U-l 1-1 o en c o c •M o ^ -U 1-1 q; o en Q* o 6 1-1 IT3 0) 4J Q< O Q4 eu D - 50 - '^: ""I., U" ■"i~. ■--1 ..---'"■^"■^ ■ y-\ A :^2> 1 A. <3 f- • Ul D 0) (0 c D ■H .H e i-H (0 >( • \-> x: 1 S (U e cn o • e u (0 ro JJ > o CU o -H X 1-1 CM > (U W 1-1 D D dJ cn C •H •H Cu e (0 i-H b4 i-l OiH-i a (0 • 0) en n-l c U-l -H c O TD W o 0) to -u a 0) 0) (0 t^ en c s: a, o o w e -H 1 U rO jj jj 0) 4-> u (0 -tJ O o o y-i CU ajD /"' ' \"^ ^ 0] •H 4J (0 3 (0 CX3 ^ ro (0 -H .» D4^ '4- (0 rH S 0 x: o CQ x: oo • ro •. W W D. 01 -H ■H )-l Ul 4-) D -P CT W IW •H 3 (0 < Cu 1— 1 (1) (0 rH oJ ro • •H P rH 1 rH u (1> x: o • -H 4J c •rH c D (0 i-i ^a tM - 61 - NAJADACEAE Najas (Naiad) Submersed annuals of fresh and sometimes saline water; leaves sub-opposite or appearing whorled; serrate or spinulose along the edges; fruit borne in the axils of the leaves; submerged. Key to Species 1. Leaf bases tapered (figs. 39B,C, 40D) . 2. Leaves acute or rounded, not sharp-pointed (figs. 39B,C); style 0.5 mm or less in length (fig. 39D) ; seed dull, with 15-18 rows of areolae (fig. 39E) . N^ guadalupensis 2. Leaves tapered to a sharp point (fig. 40D) ; style 1.0 mm or more in length (fig. 40B) ; seed shiny, with 30-40 rows of areolae (fig. 40C) . N_j^ flexilis 1. Leaf bases lobed (Figs. 41B, 42B,C). 3. Leaf blades, usually less than 0.3 mm wide (fig. 4lB) ; leaf margins not conspicuously toothed to the unaided eye (fig. 41B) ; fruit with approximately 24 rows of areolae (fig. 41D) . N^ gracillima 3. Leaf blades 0.3-0.5 mm wide (figs. 42B,C); leaf margins often conspicuously toothed to the unaided eye (figs. 42B,C) ; fruit with 12-18 rows of areolae (fig. 42D) N. minor 1. Najas guadalupensis (Spreng.) Magnus Fig. 39, Map 39 Rare but locally abundant in alkaline, acid or brackish waters at eleven widely scattered localities in New England. Range extends from southwestern Quebec and Maine west to Michigan, South Dakota, Idaho, and Oregon, south throughout the United States and Mexico. Rare and endangered plant lists: Massachusetts, Vermont alkalinity: mean 25.7 mg/1; range 19.5-41.5 mg/1 pH: mean 7.4; range 7.2-7.5 chloride: mean 413.5 mg/1; range 10.9-1201.2 mg/1 2. Najas flexilis (Willd.) Rostk. and Schmidt Fig. 40, Map 40 Extremely common throughout New England. Range extends from Newfoundland west to Minnesota, Alberta and British - 62 - - 63 - r-fK CO • X O dJ ^ .H (4-1 CU (0 CO S (0 •I— m - 64 - Columbia/ south to Virginia, Ohio, Indiana, Iowa, and Oregon. alkalinity: mean 36.5 mg/1; range 4.0-245.0 mg/1 pH: mean 7.4; range 6.4-10.2 3. N a j a s gracillima (A. Br.) Magnus Fig. 41, Map 41 Locally abundant in acid waters, mainly of southern New England. Range extends from Maine west to Minnesota, south to Virginia, Kentucky, Alabama, and Missouri; one isolated station in California. Rare and endangered plant list: Vermont alkalinity: mean 4.6 mg/1; range 2.5-9.0 mg/1 pH: mean 6.2; range 5.7-6.7 4. Najas minor All. Fig. 42, Map 42 Rare in alkaline waters of extreme western New England. This European introduction has not made much movement eastward into New England from New York where it is more abundant. Range extends from western New England west to Michigan and Indiana, south to Florida, Mississippi, and Arkansas. alkalinity: mean 101.0 mg/1; range 99.5-102.5 mg/1 pH: mean 7.8; range 7.3-8.2 Selected References Clausen, R. T. 1936. Studies in the genus Najas in northern United States. Rhodora 38: 334-345. Clausen, R. T. 1937. A new species of Najas from the Hudson River. Rhodora 39: 57-60. Fernald, M. L. 1923. Notes on the distribution of Najas in northeastern- Amer ica. Rhodora 25: 105-109. Haynes, R. R. 1977. The Najadaceae in the southeastern United States. J. Arnold Arbor. 58: 161-170. Haynes, R. R. 1979. Revision of North and Central America Najas (Najadaceae). Sida 8:34-56. Hellquist, C. B. 1977. Observations on some uncommon vascular aquatic plants in New England. Rhodora 79: 445-452. Merilainen, J. 1968. Najas minor All. in North America. Rhodora 70: 161-175. Morong, T. 1893. The Naidaceae of North America. Mem. Torrey Bot. Club 3: 1-65. - 65 - 4J •H /^ £X x