TAXONOMY NYMPHAEA MEXICANA. 



165 



Leaves of mature plant floating, or aerial and 7 to 12 cm. above the water, 

 broadly ovate to orbicular, evidently peltate, entire, or more commonly sinuate or cren- 

 ulate-wavy at base, becoming entire or slightly emarginate at apex; green above, with 

 brown mottlings, at least on the floating leaves ; under surface deep purplish-red, often 

 becoming greenish, marked with small blackish dots. Primary veins scarcely visible, 

 5 to 10 on each side, depressed from the second fork outward. Sinus short, depth : 

 length of leaf = i : 2.6 to 2.8 ; margins nearly straight, slightly separated or over- 

 lapping ; angles slightly or evidently produced, obtuse or somewhat acute, made promi- 

 nent by a deep concavity of the margin of the leaf on outer side of lobe. The aerial 

 leaves may become concave above by the overlapping of the sinus margins. Petiole 

 with two main air-canals placed transversely, and two smaller ones placed anteriorly 

 and posteriorly; stellate cells small, 

 numerous, short armed. Stipules 

 fused into a single entire lanceolate 

 organ, thin, membranaceous and 

 translucent; apex rounded; 3.3 cm. 

 long by 0.8 cm. wide, standing erect 

 and clasping the younger leaves; 

 smooth, and uniform in thickness. 



Rhizome erect (1.9 cm. long 

 by 1.4 cm. thick), becoming as 

 much as 30 cm. long and 5 to 6 cm. 

 thick (Treat 1877), densely cov- 

 ered between the leaf bases with 

 long, light-colored hairs, and on the 

 sides marked with large, projecting, 

 spirally arranged leaf cushions, 

 which are about 0.64 cm. apart 

 from center to center. From the 

 upper part of the rhizome naked 

 stolons 0.5 to i.o cm. in diameter are 

 given off; these pass along under the mud in which the plant grows for a distance of 15 

 or 20 cm. to I meter, when the terminal bud turns upward and forms a new plant ; in a 

 few weeks the new plant again sends out runners, and the connection with the parent 

 stem dies away. In autumn the stolons become geotropic and bury their tips 2O cm. 

 or more in the mud, and there form brood-bodies. A brood-body consists of an axis 

 2.5 cm. long, with a row of 3 to 6 or 7 upward pointing buds on one side, and a 

 cluster of about a dozen or more fleshy roots 1.3 to 3.8 cm. long and 0.4 to 0.48 cm. 

 in diameter hanging down like a " hand " of bananas on the other side. In spring, the 

 uppermost bud sends up a naked stolon at whose summit leaves spring up as noted 

 above; roots spring from the bases of these leaves, and soon an independent plant is 

 formed. If the first bud is broken off, the second sprouts, and so on ; probably the sec- 

 ond and lower buds would sprout sooner or later in any case, so long as the food sup- 

 ply in the fleshy roots was not used up. 



Fio. 64. Nymphaeamericcma: a, first broad leaf, b, acicular 

 leaf of seedling; c, d, e. submerged leaves of seedlings; /, first 

 floating leaf of seedling. Florida stock. Natural size. 



