Class II. ANGIOSPERA^AE, 11. Typhaceae 12. Sparganiaceae 13. Najadaceae 14. Juncaginaceae 15. Alismataceae 16. Hydrocharitaceae

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1 z- v iv c i > / i - =/ y ^ / DUPLICATE C/4 Jl dm *>J~ {T» lovfcr PART II o ^ va c^aa \?> > ^ \\\\ i,>! l0f?a! v \& / VO) A " ^ /\ ^ AA. ^ ** ' ^ Class II. ANGIOSPERA^AE, Subclass I. MONOCOTYLEDONEAE 11. Typhaceae 12. Sparganiaceae 13. Najadaceae 14. Juncaginaceae 15. Alismataceae 16. Hydrocharitaceae Agricultural Experiment Station University of Wyoming June 1963 Bulletin 404

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3 ca n c*j- C' jq- (P*ort-ev PART II Class II. ANGIOSPERMAE Subclass I. MONOCOTYLEDONEAE 11. Typhaceae 12. Sparganiaceae 13. Najadaceae 14. Juncaginaceae 15. Alismataceae 16. Hydrocharitaceae June 1963 Agricultural Experiment Station University of Wyoming Bulletin 404

4 CLASS II. ANGIOSPERMAE Deciduous or evergreen trees, shrubs, or herbs with narrow or broad leaves, the ovules and seeds enclosed in an ovary which bears one or more stigmas. SUBCLASS 1. Monocotyledoneae Mostly herbs, in ours. Flowers with their parts in threes or sixes, sometimes fewer. Vascular bundles in the stem separate and scattered as seen in cross section, not in a ring, but the stems sometimes hollow. Leaves mostly with parallel veins (nerves), often sheathing. Embryo with a single cotyledon. (In Lemnaceae stems and leaves are lacking.) KEY TO THE FAMILIES 1. Plants without stems and leaves, usually free floating but sometimes stranded; flowers minute and rarely observed 19. LEMNACEAE 1. Plants with stems and leaves, the leaves sometimes reduced to sheaths, the plants not free floating but sometimes aquatic; flowers and inflorescences usually evident 2. Aquatic plants, often forming extensive beds, with leaves whorled, sessile, oblong or lanceolate, crowded near the ends of the stems and more remote below; pistillate flower sessile between two spathe-like bracts; staminate flowers with long, thread-like perianth tube resembling a pedicel 16. HYDROC.HARITACEAE 2. Aquatic or terrestrial plants of various aspect, but not as above 3. Plants grass-like or rush-like, with chaffy flowers, inflorescences, or spikelets; underground parts consisting of fibrous roots, with or without rhizomes, but bulbs rare or lacking 4. Fruit a 3-valved capsule with 3 to many seeds; perianth of 6 chaffy and similar parts; flowers not in spikelets associated with scalelike bracts 21. JUNCACEAE 4. Fruit an akene or grain, indehiscent and 1-seeded; perianth inconspicuous, of scales, bristles, or hairs, or lacking; flowers in spikelets, associated with scale-like bracts (scales, glumes, lemmas)

5 5. Stems not jointed; leaves when present 3-ranked; fruit a lenticular or 3-angled akene 18. CYPERACEAE 5. Stems jointed; leaves present and 2-ranked; fruit a grain, seldom angled 17. POACEAE Plants sometimes grass-like, but neither the inflorescence nor the perianth chaffy; underground parts various, bulbs and corms sometimes present 6. Perianth in two distinct whorls, biseriate, the sepals or sepal-like parts green; perianth tube lacking; plants rhizomatous or annual, without bulbs or corms 7. Fruit 1-seeded or sometimes 2-seeded; plants aquatic or in wet places; petals green or white, if present 8. Plants with leafy stems 13. NAJADACEAE 8. Plants scapose, with basal leaves and naked flowering stems 9. Inflorescence a spike-like raceme, congested and elongate, without bracts; inner perianth segments (petals) green and sepaloid; leaves narrowly linear 14. JUNCAGINACEAE 9. Inflorescence a bracteate panicle or open raceme; inner perianth segments (petals) white and delicate in texture; leaves mostly lanceolate or broader 15. ALISMATACEAE 7. Fruit a 3- to many-seeded capsule or berry; plants terrestrial, either in dry, sandy places or in timbered areas; petals white to pink or purple 10. Leaves linear, alternate; plants of dry, sandy areas; petals violetpurple 20. COMMELINACEAE 10. Leaves oval, in a whorl of 3; plants of timbered areas; petals white to pink, often dtying purplish. Trillium in 22. LILIACEAE 6. Perianth mostly in a single whorl, uniseriate, the sepals not green, usually petaloid, or the whole perianth reduced to scale-like or hair-like parts; perianth tube sometimes present; plants sometimes with bulbs or corms 11. Flowers unisexual; perianth of hairs or scales, not petaloid; plants aquatic or in wet places 12. Flowers in dense, cylindrical spikes, these single on the ends of the stems, staminate above and pistillate below II. TYPHACEAE 12. Flowers in dense, globose heads, these few to many, the upper ones staminate and the lower ones pistillate 12. SPARGANIACEAE 11. Flowers perfect; perianth usually petaloid and often showy; plants terrestrial but sometimes in wet places 13. Flowers hypogynous; stamens usually 6, rarely Flowers epigynous; stamens 3 or fewer 22. LILIACEAE 14. Stamens 3; flowers regular; ovary and fruit 3-celled 23. IRIDACEAE 14. Stamens 1 or 2; flowers irregular; ovary and fruit 1-celled 24. ORCHIDACEAE

6 11. TYPHACEAE Cattail Family Tall marsh or aquatic herbs with fleshy rhizomes and long, 2-ranked, linear, sheathing leaves. Flowers monoecious, in dense, cylindrical, terminal spikes that are staminate above and pistillate below. Staminate flowers of usually 3 stamens, each flower surrounded by a hair-like perianth of indefinite parts. Pistillate flowers with a single pistil, the ovary long-stipitate, the stipe bearing numerous perianth-hairs. Fruit l-seeded and indehiscent or tardily dehiscent. 1. Typha L. Cattail The only genus, with characters as given for the family. KEY TO THE SPECIES Stems stout; staminate and pistillate portions of spike contiguous or nearly so; pistillate flowers without bractlets; stigma flat; pollen grains adhering in groups of 4 (tetrads) 1. T. latifolia Stems slender; staminate and pistillate portions of spike separated by an interval of at least 5 mm.; pistillate flowers with bractlets; stigma thread-like; pollen grains separate 2. T. angustifolia 1. Typha latifolia L. Common Cattail Common in marshes and borders of shallow lakes, at lower elevations, and widely dispersed throughout Wyoming. Ranging across North America; also in Europe and Asia. 2. Typha angustifolia L. Narrowleaf Cattail Marshes and ditches at lower elevations, and occasional in Wyoming, but fairly common in the Bighorn Basin. Widely distributed in the northern hemisphere; also in Central and South America and Africa. 12. SPARGANIACEAE Bur-reed Family Monoecious, perennial, grass-like, aquatic, or marsh herbs with erect or floating stems mostly 1 m. long or less, from rhizomes rooted in the mud. Leaves linear, alternate, 2-ranked, and sheathing, erect, or floating. Inflorescence of a few to several globose heads that are pedunculate or sessile, the upper head or heads staminate and the lower pistillate. Staminate flowers soon falling from the axis. Pistillate heads persistent, produced from the axils of leaf-like bracts and axillary, or sometimes apparently produced from a point above the axil of a leaf-like bract because of adnation of the peduncle with the axis, and then supra-axillary. Perianth of a few scales. Stamens 3 or more, often 5. Pistil 1, the ovary narrowed at the base, the styles 1 or 2. Fruit an akene, usually beaked, and often stipitate.

7 1. Sparganium L. Bur-reed The only genus, with characters as given for the family. KEY TO THE SPECIES Stigmas usually 2; akenes obpyramidal, abruptly rounded or truncate at the apex, sessile; sepals nearly as long as the akene; plants up to 1 m. high; leaves keeled; inflorescence often compound 1. S. eurycarpum Stigma 1; akenes fusiform, tapering upward, usually stipitate; sepals much shorter than the akene; plants lower; leaves erect or floating, flat, rounded on the back, or keeled; inflorescence simple Fruiting heads about 1 cm. in diameter, all axillary; staminate head usually solitary; stipes and beaks of akenes less than 1 mm. long or the akenes subsessile 2. S. minimum Fruiting heads at least 1.5 cm. in diameter, at least some of them supra-axillary; stipes and beaks of akenes each at least 2 mm. long Leaves 2-4 mm. wide, not scarious-margined, usually rounded on the back, not keeled, the floral leaves broadened at the base; stems and leaves usually floating 3. S. angustifolium Leaves 5-9 mm. wide, with scarious margins near the base, mostly strongly keeled or sometimes flat on the back, the floral leaves not broadened at the base; stems and leaves often erect and emersed 4. S. multipedunculatum 1. Sparganium eurycarpum Engelm. In mud, shallow water, or shores of lakes and ponds, at lower elevations, the single Wyoming collection seen from Sheridan County. Quebec and Nova Scotia to British Columbia, and southward to New Jersey, Indiana, Kansas, Colorado, Arizona, and California. 2. Sparganium minimum (Hartm.) Fries In mud, ponds, and lakes, at middle elevations, about 6,000-8,000 ft., and apparently limited to northwestern Wyoming. Circumboreal; Newfoundland to Alaska, and southward to Connecticut, New Jersey, Pennsylvania, Michigan, Wisconsin, Colorado, Utah, and Oregon. 3. Sparganium angustifolium Michx. Shallow to moderately deep water of ponds and lakes, at about 6,500-10,800 ft., and generally distributed in Wyoming. Newfoundland to Alaska, and southward to New Jersey, Pennsylvania, Michigan, Colorado, and California. 4. Sparganium multipedunculatum (Morong) Rydb. In mud of ditches, shores, ponds, and lakes, at about 4,500-8,000 ft., and generally distributed in Wyoming. Labrador to Alaska, and southward to New Hampshire, Vermont, Colorado, and California.

8 13. NAJADACEAE Pondweed Family Aquatic herbs with leafy stems, the leaves alternate or opposite, all submersed or the upper floating, the submersed leaves sometimes reduced to phyllodia. Flowers small, axillary or in terminal spikes, unisexual or perfect, without a true perianth (in Potamogeton there are 4 sepaloid structures that are variously interpreted as sepals, bracts, or dilated connectives of stamens), the stamens 4, 2, or 1, the pistils 1-4. Fruit 1-seeded and indehiscent, usually an akene. KEY TO THE GENERA Flowers and fruits in terminal, pedunculate spikes; leaves alternate, broad or narrow, submersed or floating 1. POTAMOGETON Flowers and fruits not in terminal spikes; leaves alternate or opposite, narrowly linear, submersed Leaves alternate, with broadened sheaths; flowers produced within the leaf-sheaths but after anthesis elevated on a long, coiled peduncle; fruits long-stipitate 2. RUPPIA Leaves opposite, with narrow sheaths; flowers and fruits in sessile groups of 1-5 (usually 4) in the leaf-axils 3. ZANNICFfELLIA 1. Potamogeton L. Pondweed Aquatic perennials in shallow or deep water, with slender rhizomes. Leaves alternate or the uppermost sometimes opposite, broad or narrow, with sheathing stipules, all submersed and alike, or the upper leaves floating and then somewhat unlike the submersed leaves, and sometimes the submersed leaves reduced to phyllodia. Flowers in terminal, pedunculate, short or elongate spikes, with 4 stamens, each stamen aclnate to a sepaloid structure variously interpreted as a sepal, an involucral bract, or a dilated connective of the stamen, the 4 distinct pistils becoming more or less beaked akenes in fruit. KEY TO THE SPECIES 1. All leaves 5 mm. broad or less, all linear or setaceous, all submersed 2. Leaves 1-nerved, more or less septate by cross partitions 3. Sheaths 4-22 mm. long, mostly connate at the base 1. P. filiformis 3. Sheaths mm. long, open to the base 4. Lower sheaths inflated, much exceeding the stem in width, abruptly contracted into the blade; whorls of flowers and fruits equidistant; style obsolete 2. P. vaginatus 4. Lower sheaths not inflated, not much exceeding the stem in width, gradually tapering into the blade; whorls of flowers and fruits unequally distant, the lower more remote; style short but evident 3. P. pectinatus 2. Leaves with 3 or more nerves, mostly not septate

9 5. Nerves 7 or less 6. Leaves glandless; peduncle clavate; fruits with a thin or acute, undulate to dentate, dorsal keel 4. P. [oliosus 6. Leaves usually with a pair of basal glands; peduncle filiform or with a slightly broadened tip; fruits rounded on the back, not keeled 7. Stipules strongly fibrous, becoming whitish; leaves 3-7-nerved; peduncles slightly broadened at the tip; winter buds covered by strongly fibrous, white stipules 8. Leaf blades flat, obtuse, mm. broad, with 5-7 nerves; lacunae present 5. P. friesii 8. Leaf blades usually revolute, mm. broad, with 3 nerves; lacunae absent 6. P. strictifolius 7. Stipules scario-membranaceous, olivaceous; leaves 3-nerved; peduncle filiform, not enlarged at the tip; winter buds with scarious but not strongly fibrous stipules 7. P. pusillus 5. Nerves 20 or more 9. Stem flattened at internodes, constricted at nodes; leaves not distichous, not auricled at the base, linear and grass-like; nerves up to 35, 3 of them larger and more prominent 8. P. zosteriformis 9. Stem not flattened at internodes, not constricted at nodes; leaves strictly 2-ranked, distichous, auricled at base, linear to lanceolate; nerves 20-60, all alike 9. P. robbinsii Some or all leaves more than 5 mm. broad, linear to elliptical or ovate; plants with or without floating leaves 10. Margins of leaves sharply serrulate to the naked eye 10. P. crispus 10. Margins of leaves entire or nearly so 11. Leaves all submersed, never dilated and floating, all cordate or rounded at base, abruptly sessile or clasping 12. Rhizomes with rusty-red spots; leaves mostly cm. long, often cucullate at apex; stipules conspicuous, rigid, 3-10 cm. long, usually persistent; fruits 4-5 mm. long, mm. wide, with a strong dorsal keel 11. P. praelongus 12. Rhizomes not spotted; leaves 1-10 cm. long, acutish to blunt; stipules whitish, coarsely nerved, 1-2 cm. long, soon disintegrating into stringy, white fibers; fruits mm. long, 2-3 mm. wide, with dorsal keel less pronounced 12. P. richardsonii 11. Leaves normally of two forms, the dilated, floating leaves sometimes not developed; submersed leaves petioled or tapering to the sessile base, not abruptly sessile or clasping 13. Mature, floating leaves at most 3.5 cm. long; submersed leaves linear to linear-setaceous, mm. broad; fruits cochleate, the spiral curve of the embryo clearly evident through the pericarp 14. Submersed leaves obtuse, usually rounded at the tip; connate portion of sheath much longer than the free stipular tip; fruits mm. in diameter, lateral keels scarcely developed, the sides rounded 13. P. spirillus

10 14. Submersed leaves subobtuse to acute; connate portion of sheath half as long as the free tip; fruits mm. in diameter, lateral keels fine but definite, the sides flat or depressed 14. P. diversifolius Mature floating leaves more than 4 cm. long; submersed leaves mostly broader, ribbon-like to spatulate or ovate, sometimes reduced to phyllodia; fruits not cochleate (incompletely coiled in P. epihydrus) 15. Stem flattened; submersed leaves ribbon-like, often strongly distichous, the median band each side of the midrib largely composed of reticulate lacunae; fruits strongly laterally flattened; embryo incompletely coiled 15. P. epihydrus 15. Stem terete; submersed leaves linear-lanceolate to ovate or elliptical (sometimes bladeless), not distichous, less lacunate; fruit with rounded sides, the embryo curved into a partial ellipse 16. Submersed leaves sessile, reddish or fulvous-olivaceous; floating leaves, when developed, translucent and tapering without sharp distinction into the petiole; exocarp of fruit hard and smooth, tawny-olive 16. P. alpinus 16. Submersed leaves sessile or petiolate, not reddish, floating leaves coriaceous, dense or opaque, with sharp distinction between petiole and cordate- to cuneate-based blade; exocarp of fruit soft and porous, greenish, brownish, or reddish 17. Submersed leaves broadly linear to ovate, less than 30 times longer than broad, with 3-37 definite nerves; floating blades with their midribs continuing the direction of the straight petiole 18. Margins of submersed leaves entire, their blades arcuate, cm. broad; floating leaves with mostly nerves 17. P. amplifolius 18. Margins of submersed leaves with fugacious, 1-celled, translucent denticles, their blades mostly straight, no more than 4.5 cm. broad, the nerves 3-29; floating leaves with nerves mostly fewer than Submersed leaves with petioles 2-13 cm. long, their blades acutish but neither sharp-pointed nor mucronate; fruits mm. long, usually reddish, their keels usually muricate 18. P. nodosus 19. Submersed leaves sessile or with petioles rarely 4 cm. long, sharp-pointed or often mucronate; fruits mm. long, mostly greenish to drab, with scarcely muricate keels 20. Stem usually repeatedly branched, mm. thick; submersed leaves cm. wide, five to thirty times longer than broad, sessile, their nerves mostly 3-9; floating leaves cm. long and 1-3 cm. wide, their petioles mostly longer than the blades; stipules cm. long, only faintly keeled; fruiting spikes cm. long; fruits mm. broad 19. P. gramineus 20. Stems simple or once-branched, 1-5 mm. thick; submersed leaves cm. wide, three to five times longer than broad, sessile or petiolate, their nerves mostly 9-17; floating leaves 4-19 cm. long, cm. wide, their

11 1. Potamogeton filiformis Pers. petioles mostly shorter than the blades; stipules 1-8 cm. long, prominently keeled; fruiting spikes cm. long; fruits mm. broad 20. P. illinoensis 17. Submersed leaves mostly bladeless; blades of floating leaves 4-12 cm. long and cm. wide, usually cordate at the base, with petioles mm. thick, the midrib of the blade often forming an angle with the twisted petiole; stipules strongly keeled to the tip; fruiting spikes 9-12 mm. thick; mature fruits mm. broad, scarcely keeled 21. P. natans This species is represented in Wyoming by two fairly easily distinguished varieties: var. borealis (Raf.) St. John, having filiform and very slender-tipped leaves, the stems mostly less than 4 dm. long, and var. macounii Morong, having narrowly linear but scarcely filiform leaves with blunt tips, the stems often much longer, especially in flowing water. Common in quiet or flowing, fresh or somewhat alkaline water, at lower to middle elevations, throughout most of Wyoming. Ranging across northern North America from Newfoundland to Alaska, and southward to Pennsylvania, Nebraska, New Mexico, Arizona, and northern California; also Eurasia. 2. Potamogeton vaginatus Turcz. In fairly deep water of lakes, developing stems often 1-3 m. long, on plains and foothills. Ranging across northern North America from Newfoundland to Alaska, and southward to the Great Lakes region, Colorado, and Oregon; also Eurasia and Africa. 3. Potamogeton pectinatus L. Common and often forming extensive beds in fresh or usually saline water of lakes and ponds, at lower to middle elevations. Cosmopolitan. 4. Potamogeton foliosus Raf. Two doubtfully distinct varieties occur in Wyoming: var. foliosus, with long internodes and stems 5-10 dm. long, and var. macellus Fern., with short internodes and shorter, more bushy stems, the latter being our more common plant. Potamogeton fibrillosus Fern., said to differ from P. foliosus in having sheaths that disintegrate into coarse fibers, appears to be only a form of P. foliosus produced by rather warm water conditions of geyser formations and hot springs in Yellowstone National Park. The warm water hastens disintegration of the sheaths by bacterial action. Shallow ponds and lakes, ditches, and sluggish streams, at lower to middle elevations. Newfoundland to Alaska, and southward to the West Indies and Mexico. 9

12 5. Potamogeton friesii Rupr. Apparently infrequent in Wyoming, in subalpine lakes and ponds, at about 6,000 to 8,500 ft. Newfoundland to Mackenzie District, and southward to the Great Lakes region, South Dakota, Wyoming, and British Columbia. 6. Potamogeton strictifolius Ar. Benn. In shallow lakes, ponds, and sluggish streams, at lower to middle elevations. Quebec to Mackenzie District, and southward to New York, Indiana, Nebraska, Wyoming, and northern Utah. 7. Potamogeton pusillus L. According to some authorities this includes two entities: P. pusillus, having sheaths closed or connate to the middle, and P. berchtoldii Fieb., having sheaths open to the base. The connation of the sheaths, however, seems to be a variable character, and since the fruits are not distinguishable it seems best to combine these two into a single, variable species. Common in shallow lakes, ponds, and ditches, at lower to middle elevations, up to about 9,000 ft. in Wyoming. Widely distributed in the Northern Hemisphere. 8. Potamogeton zosteriformis Fern. Apparently rare in Wyoming, where it is known only from Swan Lake, in Teton National Park, in shallow water with Nuphar, and there abundant. Ranging across southern Canada and the northern United States. 9. Potamogeton robbinsii Oakes Occasional but often locally abundant, in subalpine lakes, often in water up to 10 ft. deep, the plants sterile but readily identified by their frond-like, distichous-leaved stems, the leaves usually curving downward near their ends. Northeastern United States and southeastern Canada, and in the western United States from Wyoming to British Columbia, and southward to California. 10. Potamogeton crispus L. Not known to occur in Wyoming, but found in northern Colorado and perhaps to be expected. Often forming large beds in lakes and sluggish streams, at lower to middle elevations. Northeastern United States and adjacent Canada; Colorado (perhaps introduced); California; also Europe. 11. Potamogeton praelongus Wulfen Apparently rare in Wyoming, in cold mountain lakes. Readily identified by its large leaves and white, zigzag stems. Across northern North America; also Eurasia. 10

13 12. Potamogeton richardsonii (Ar. Benn.) Rydb. Very common and often forming large beds in shallow lakes, ponds, reservoirs, and sluggish streams, at lower to middle elevations. Readily distinguished by its undulate, clasping leaves. Widespread across northern North America. 13. Potamogeton spirillus Tuckerm. Shallow ponds and lakes at lower to middle elevations, and known for Wyoming only from the Bear Lodge Range, Crook County. Newfoundland to eastern Manitoba, and southward to Virginia, Ohio, Iowa, South Dakota, and northeastern Wyoming. 14. Potamogeton diversifolius Raf. Not known to occur in Wyoming, but perhaps to be expected. It is similar to P. spirillus, but it has a more southern distribution, ranging from the Gulf States northward to New Jersey, Ohio, South Dakota, Montana, Oregon, and California; also Mexico. 15. Potamogeton epihydrus Raf. Readily identified by its well-developed floating leaves and slender, ribbon-like submersed leaves. Our plants are probably all referable to var. nuttallii (C. & S.) Fern., supposedly distinguished by a somewhat smaller size than var. epihydrus. It seems unlikely that the varietal distinction is significant. Occasional in Wyoming, in mountain lakes and ponds, up to about 10,000 ft., and often associated with Nuphar. Ranging across the northern United States and southern Canada. 16. Potamogeton alpinus Balbis Wyoming collections are probably all referable to var. tenuifolius (Raf.) Ogden, having linear-oblong or linear-lanceolate submersed leaves. Usually distinguished by the reddish coloration of the terminal parts. Common in montane or subalpine ponds, lakes, and sluggish streams. Greenland to Alaska, and southward to New York, Wisconsin, Colorado, and California; also Eurasia. 17. Potamogeton amplifolius Tuckerm. Occasional in cold, deep lakes in the mountains, at about 9,000-10,000 ft. Quebec to British Columbia, and southward to Alabama, Oklahoma, and California. 11

14 18. Potamogeton nodosus Poir. Occasional in gently flowing streams and rivers, but often locally abundant, especially in the Madison River, Yellowstone National Park. Cosmopolitan. 19. Potamogeton gramineus L. The species is variable, particularly in size and shape of the submersed leaves. The var. maximus Morong ex Ar. Benn. has submersed leaves large, 7-13 cm. long. Some of our plants may be this variety. Ponds, lakes, and sluggish streams in the mountains and valleys. Widely distributed in the northern part of the Northern Hemisphere. 20. Potamogeton illinoensis Morong Infrequent in sluggish streams, at lower elevations, on the plains and foothills. Ranging across southern Canada and throughout most of the United States. 21. Potamogeton natans L. In swift water, such as parts of the Madison River in Yellowstone National Park, the plants are kept more or less submerged by the force of the flowing water, and this seems to prevent the formation of well-developed floating leaves. The phyllodes, of linear, submersed leaves, then become well developed. Under ordinary conditions, however, the floating leaves are very distinctive, having some of their blades produced at an angle to the petiole instead of continuous with its direction. Frequent in ponds, lakes, and streams, mostly at lower elevations, but also found in the lower mountains. Widely distributed in the northern part of the Northern Hemisphere. 2. Ruppia L. Ditch Grass Submersed, rhizomatous perennials of alkaline ponds and lakes. Stems branching, often zigzag. Leaves alternate, up to 1 dm. long, narrowly linear, with dilated, membranaceous, stipular sheaths at the base, and tapering above into long, capillary tips. Flowers naked, produced in the upper sheaths on coiled peduncles that elongate to elevate the flowers to the water surface, where pollination occurs, and then usually retracted. Each peduncle bearing 2 unisexual flowers, the staminate consisting of 2 sessile anthers, the pistillate, maturing later, consisting of 4 stipitate pistils. Fruits long-stipitate, in an umbel-like cluster, ovoid, unsymmetrical, and 1-seeded. 12

15 1. Ruppia maritima L. A highly variable complex that is treated here as a single species, but by some authors regarded as at least two species or as several varieties, based on slight differences in the shape of the fruits and on whether or not the peduncles recoil after anthesis. In our plants the peduncles may coil after anthesis, which is a characteristic of plants described as R. spiralis Dum. Fairly common in lakes 011 the plains and in the foothills of Wyoming, in water up to about 6 ft. deep. Cosmopolitan. 3. Zannichellia L. Horned Pondweed Submersed, delicate, branching, often matted, rhizomatous perennials. Leaves opposite, filiform, flat, 1-nerved, mostly 2-6 cm. long, with sheathing, membranaceous stipules. Flowers naked, unisexual, in the leaf axils, the staminate solitary and consisting of a single anther on a slender filament, the pistillate usually 4 (1-5) at a node, each consisting of a short-stipitate pistil. Fruit flattened, obliquely oblong, with a slender beak, 2-4 mm. long, 1-seeded. 1. Zannichellia palustris L. Common in shallow, fresh, or saline ponds, lakes, and ditches, usually at lower elevations. Cosmopolitan. 14. JUNCAGINACEAE Arrowgrass Family Scapose marsh herbs with long, narrow, semiterete leaves that are sheathing at the base, the sheath ending above in an entire or 2-lobed ligule. Scape terminating in a spike-like inflorescenec of numerous, small, perfect, ebracteate, hypogynous, greenish flowers. Perianth (or perhaps perianth-like appendages) consisting of 6 concave parts that are deciduous with the stamens. Anthers 6 or 3, nearly sessile. Carpels 6 or 3, weakly united, each 1-seeded at maturity and akene-like in fruit. 1. Triglochin L. Arrowgrass Our only genus, with characters as given for the family. 13

16 Carpels 6, obtuse at the base at maturity KEY TO THE SPECIES Ligules entire, denticulate, or emarginate; rhizomes thick and contracted; old leaf bases persistent for several seasons, indurate-corky; scapes mostly 6 dm. high or more in fruit 1. T. maritime Ligules 2-parted to the base; rhizomes slender and creeping; old leaf bases evanescent or merely fibrous in age; scapes mostly 1-4 dm. high 2. T. concinna Carpels 3, tapering at the base at maturity 1. Triglochin maritima L. 3. T. palnstris Common in alkaline marshes, meadows, and borders of lakes, at lower to middle elevations. Widely distributed throughout the Northern Hemisphere. 2. Triglochin concinna Davy Wyoming plants are all var. debilis (M. E. Jones) J. T. Howell, which differs from var. concinna in being coarser, with more flowers in the inflorescence, and the base of the stem and the rhizome usually covered with coarse fibers of the sheaths. Alkaline marshes, meadows, and borders of lakes, at lower to middle elevations. Apparently less common in Wyoming than T. maritima. Ranging from the Dakotas westward to Oregon, and southward to Colorado, Arizona, and eastern California. 3. Triglochin palustris L. Alkaline marshes, meadows, and borders of lakes, at lower to middle elevations, and fairly common in Wyoming. Greenland to Alaska, and southward to Pennsylvania, Iowa, Colorado, and British Columbia; also Eurasia. 15. ALISMATACEAE Water Plantain Family Scapose marsh or aquatic herbs, with broad, long-petioled, sheathing leaves, or sometimes the leaves reduced to ribbon-like phyllodia. Scape terminating in an open, bracteate raceme or panicle. Flowers regular, hypogynous, perfect, polygamous, monoecious, or dioecious. Perianth of 3 green sepals and 3 white (rarely pinkish), deciduous petals. Stamens 6 or more. Pistils (carpels) numerous, distinct, arranged in a ring or in a globose head, becoming akenes in fruit. KEY TO THE GENERA Akenes arranged in a ring; leaves never sagittate; flowers perfect 1. ALISMA Akenes in a dense, globose head; leaves often sagittate; at least the upper flowers in the inflorescence staminate 2. SAGITTARIA 14

17 1. Alisma L. Water Plantain Scapose marsh or aquatic herbs with sheathing leaves having lanceolate to oval blades, or the leaves sometimes reduced to ribbon-like phyllodia. Inflorescence an open panicle of small, perfect flowers, the petals in ours 3-6 mm. long. Pistils (carpels) and akenes in a ring. KEY TO THE SPECIES Leaf blades up to 25 mm. broad, the leaves often reduced to ribbon-like phyllodia; plants often submersed; inflorescence not much exceeding the leaves and usually much shorter E A. geyeri l eaf blades mostly mm. broad, the leaves not reduced to phyllodia; plants seldom submersed; inflorescence much exceeding the leaves 2. A. plantago-aquatica 1. Alisma gey eri Torr. A highly variable species in which the plants are variously modified by the depth of water and other factors. Occasional in Wyoming, and known only from alkaline ponds and reservoirs on the plains in Albany County, but to be expected elsewhere. Quebec to Alberta and eastern Washington, and southward to New York, Colorado, Nevada, and California. 2. Alisma plantago-aquatica L. American plants differ only slightly from those of the Old World, and have been designated as ssp. brevipes (Greene) Samuelsson. Occasional but often locally abundant, at lower to middle elevations, on the plains and foothills of the eastern half of Wyoming, but to be expected in western Wyoming also. Southern Canada and northern United States; also Eurasia. 2. Sagittaria L. Arrow-head Scapose marsh herbs, with erect or floating, sheathing leaves, the mature blades usually sagittate but these sometimes linear in juvenile or submersed leaves. Inflorescence an open raceme or panicle. Petals 8-20 mm. long. Pistils (carpels) and akenes in a globose head, spirally arranged. KEY TO THE SPECIES Beak of mature akene erect, minute, less than 0.5 mm. long; throughout Wyoming ' S. cuneata Beak of mature akene horizontal or oblique, mm. long; southeastern Wyoming 2. S. latifolia 15

18 1. Sagittaria cuneata Sheld. Submersed or emersed in ponds, lakes, and margins of streams, throughout Wyoming, at lower to middle elevations, and sometimes in subalpine lakes and ponds. Nova Scotia and Quebec to British Columbia, and southward to Indiana, New Mexico, and California. 2. Sagittaria latifolia Willd. Emersed in ponds, lakes, and margins of streams and ditches, at lower elevations in southeastern Wyoming, but perhaps to be expected all along the eastern border. Nova Scotia to British Columbia, and southward to Florida, Mexico, and California. 16. HYDROCHARITACEAE Frog's bit Family Ours are submersed or floating, aquatic herbs, often forming extensive beds. Leaves sessile, in whorls at the nodes or sometime paired. Flowers dioecious or polygamous, subtended by a spathe, epigynous, regular, the perianth of 6 segments. Staminate flowers rising to the surface on a long, thread-like stalk and becoming detached. Pistillate flowers with an elongated, pedicel-like hypanthium tube. Ovary 1-celled, with parietal placentation. Stigmas 3, each 2-lobed. Fruit indehiscent, fewseeded. 1. Elodea Michx. Waterweed Our only genus, with characters as given for the family. 1. Elodea canadensis Michx. Common in ponds, lakes, and sluggish streams, at lower to higher elevations, up to about 10,500 ft., throughout most of Wyoming. Quebec to Washington, and southward to Alabama, Illinois, Oklahoma, Arizona, and California; introduced in Europe. 6-6S 5M 12 University of Wyoming Agricultural Experiment Station N. W. Hilston, Director Laramie 16

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