5^ FLORA. 



depressed-globose, 7-10 mm. in diameter ; achenes 2-2.5 nim - ' on g» cuneate, with 

 a narrow dorsal wring and a very short ascending or horizontal beak. Margins 

 of brackish ponds and tide-water marshes, N. B. to Va. July-Aug. 



4. Lophotocarpus spathulatus J. G. Smith. Low aquatic, 3-7 cm. high ; 

 phyllodes bladeless or sometimes spatulate at the tip, ascending, with the edges 

 vertical through a twist in the base, 3-6 mm. wide, obtuse or rounded at the apex. 

 Scape simple, usually shorter than the phyllodes, 3-4 cm long, one- or two-flow- 

 ered, thickened, relhxed after flowering ; bracts scarious, broadly ovate, ob- 

 itamens 6-9, the filaments flattened, incurved, broadest at the base, 1.5-2 

 mm. long, glabrous ; anthers I mm. long, oblong ; sepals oblong-orbicular, 3 mm. 

 long, nerveless, thin, scarious on the margins, and papery in fruit; petals ovate- 

 orbicular, obtuse, shorter than the sepals; achenes 1-5 mm. long, obovate, obtuse, 

 narrowly winged on the back to about the level of the beak and sometimes with a 

 transverse lateral ridge near the tip; beak slender, oblique or horizontal. Sandy 

 beaches above salt-water but within the influence of tides. Newburyport, Mass. 

 Type collected by A. A. Eaton, 1898. 



4. SAGITTARIA L. 



Ferennials. mostly with tuber-bearing or nodose rootstocks, basal long-petioled 

 nerved leave-, the nerves connected by numerous veinlets, and erect, decumbent or 

 floating scapes, or the leaves reduced to bladeless phyllodes. Flowers monoecious 

 or dioecious, borne near the summits of the scapes in verticils of 3's, pedicelled, 

 the staminate usually uppermost. Verticils 3-bracted. Sepals persistent, those of 

 the pistillate flowers reflexed or spreading in our species. Petals 3, white, decid- 

 uous. Stamens inserted on the convex receptacle ; staminate flowers sometimes 

 with imperfect ovaries. Pistillate flowers with numerous distinct ovaries, sometimes 

 with imperfect stamens ; ovule solitary ; stigmas small, persistent. Achenes num- 

 erous, densely aggregated in globose or subglobose heads, compressed. Seed erect, 

 curved. [Latin, referring to the arrow-shaped leaves of some species.] About 30 

 species, natives of temperate and tropical regions. Besides the following, some 

 10 others occur in the southern and western parts of N. Am. 



Fertile pedicels slender, ascending, not reflexed in fruit. 

 Leaf-blades sagittate; filaments glabrous. 



Basal lobes one-fourth to one-half the length of the blade. 

 Beak of the achene more than one-fourth its length. 

 Beak of the achene erect. 



Fruiting pedicels shorter than the bracts ; leaves broad. 



1. S. longirostra. 

 Fruiting pedicels longer than the bracts; leaves narrow. 



2. 6". Engelmanniana. 

 Beak of the achene horizontal or oblique. 3. S. iati/olia. 



Beak of the achene less than one-fourth its length. 



Petioles rather short, curving ; bracts long ; bog species. 



4. S. ar if olid. 

 Petioles elongated; bracts short; aquatic species. 



5. S. cuneata. 

 Basal lobes two-thirds to three-fourths the length of the blade. 



6. .V. longiloba. 

 Leaf-blades entire, or rarely hastate or cordate. 



li laments slender, tapering upward; leaves seemingly pinnately veined. 

 Filaments glabrous; bracts connate. 7. S. ambigua* 



Filaments cobwebby-pubescent; bracts mostly distinct. 



8. iS". lanpifolia. 

 Filaments abruptly dilated, pubescent; veins distinct to the base of the blade. 

 Fruiting heads sessile or very nearly so. 9. S. rigida. 



Both staminate and pistillate flowers pedicelled. 



Leaves reduced to terete nodose phyllodes, rarely blade-bearing. 



10. S. teres. 

 Leaves reduced to flat nodeless phyllodes, rarefy blade-bearing ; petals 



with a rose-colored spot at 11. .S'. Eatoni. 



Leaves ri^'id ; blades elliptic-linear. 12. .5'. cristata. 



Leaves not rigid; blades lanceolate or linear-oblong, phyllodes flat, 

 nodose; petals white. 13. S. ±r\:rrii/iea. 



