Class 2. ANGIOSPERMAE. Seed-vesseled Plants. 

 Subclass I. MONOCOTYLEDONES. 



Family 5. TYPHACEAE. Cat-tail Family. 



1. TYPHA (Tourn.) L. Cat-tail, Cat-tail Flag. 



Racemes with the staminate and pistillate portions usually separate; pollen of simple 

 grains; fruiting pedicels short, 1 mm. long or less. 1. T. angustifolia. 



Racemes with the staminate and pistillate portions usually contiguous; pollen-grains 

 in 4's; fruiting pedicels bristle-like, 2-3 mm. long. 2. T. lati folia. 



Family 6. SPARGANIACEAE. Bur-reed Family. 



1. SPARGANIUM (Tourn.) L. Bur-reed. 



Achenes broadly obovoid or cuneate-obpyramidal, sessile, long-beaked: stigmas usually 



2; leaves somewhat keeled. 1. S. eurycarpum. 



Achenes fusiform (in S. minimum somewhat obovoid, but then short-beaked and short- 

 stipitate); stigmas soUtary. 

 Stipe and beak of the fruit each 2 mm. long or more; fruiting heads 1.5 cm. in diam- 

 eter or more; anthers 3-4 times as long as broad. 

 Leaves, at least the middle ones, strongly triangular-keeled ; fruiting heads about 

 3 cm. in diameter; achenes brown, gradually tapering into the beak, which is 

 fully as long as the body. 2. S. si7nvlex. 



Leaves not keeled or only slightly so, narrow and slender; stem often floaous- 

 beak of the achenes decidedly shorter than the body. 

 Leaves usually 5-10 mm. wide, as well as the bracts conspicuously scarious- 

 margined; heads 1.7-2 cm. in diameter; achenes gradually beaked. 



3. S. muUipedunculatum. 

 Leaves 3-4 mm. wide, not conspicuously scarious-raargined ; heads about 1.5 

 cm. in diameter; achenes abruptly beaked. 4. S. angustifolium. 



Stipe and beak of the fruit short, less than 1 mm. long: fruiting heads about 1 cm. 

 in diamater; stigmas oolong; anthers 1.5-2 times as long as bioad. 



5. S. minimum. 



Family?. ZANNICHELLIACEAE. Pondweed Family. 



stamens 4, the connectives with dilated appendages ; drupelets sessile. 1. Potamogeton. 

 Stamens 1-2, the connectives without appendages; drupelets manifestly stipitate. 



stigmas sessile; anthers 2; flowers perfect, on long peduncles. 2. Ruppia. 



Stigma termhiating a long style; anther 1 ; flowers monoecious, the two kinds together 

 in the same axils. 3. Zannichellia. 



1. POTAMOGETON (Tourn.) L. Pondweed, Fishweed. 



Species with both floating and submerged leaves. 



Submerged leaves bladeless. 1. P. nutans. 



Submerged leaves with proper blades. 



Submerged leaves of two kinds, oval or oblong ones and lanceolate and strongl v 



curved ones; floating leaves with 30 or more nerves. 2. P. amplifolius. 



Submerged leaves of only one kind; floating leaves with less numerous nerves. 

 Stipules free from the petioles and blades. 

 Submerged leaves lanceolate. 



Submerged leaves all petioled, more than 7-nerved. 3. P. americanus. 

 Submerged leaves all sessile or the uppermost short-petioled. 



Peduncles of the same thickness as the stem ; leaves not serrulate at 

 the apex. 

 Plant green; submerged leaves narrower than the floating ones. 



7. P. heterophyllus. 

 Plant red; submerged leaves as wide as the floating ones or 

 wider. 4. P. alpinus. 



Peduncles thicker than the stem; leaves serrulate at the apex. 



5. P. auguslifolius. 

 Submerged leaves linear. 



Submerged leaves of nearly the same width throughout, coarsely reticu- 

 late in the middle. 6. P. epihydrus. 

 Submerged leaves broader below the middle, without reticulation. 



7. P. helerophyllus. 

 Stipules adnate to the base of the Linear-setaceous submerged leaves. 



8. P. diversifolius. 

 Species with submerged leaves only. 



Leaves with broad blades, lanceolate or oval, many-nerved. 



Leaves short-petioled or sessile, not amplexicaul. 9. P. lucens. 



Leaves more or less amplexicaul. 



Leaves elongate-lanceolate, semi-ample.xicaul, cucullate; the straight apex of 

 the embryo pointing to the base of the fruit. 10. P. praelongus. 



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