6l6 PATAGONIAN EXPEDITIONS I BOTANY. 



A2. Land plants with broad leaves and mostly dioecious spiked 2-merous flowers. Carpels 2, 

 styles 2, but seed i, stamens 1-8. 2. Gunnera, p. 617. 



A$. Aquatic plants with whorled narrow leaves and polygamous, i-merous flowers. Carpel i, 

 style i, seed i, stamen i. 3. Hippuris, p. 618. 



1. MYRIOPHYLLUM Linn. 



The submersed leaves divided into capillary segments ; emersed leaves, 

 if any, less divided. Flowers axillary, 2-bracted, usually monoecious, the 

 males above; sometimes dioecious; 2-4-merous and diplostemonous. 

 Ovary 2-4-celled ; cells i-ovuled. Styles 4. Fruit splitting into 4 meri- 

 carps. 



Species 20, extra-tropically cosmopolitan. (Fig. in Eng. & Prantl, iii, 



7. P- 234-) 



i. M. ELATINOIDES Gaud. 



Monoecious or dioecious. Leaves 3-5-whorled, the lower capillaceo-mul- 

 tifid ; the upper shorter, lanceolate to ovate or broad-oblong, occasionally 

 opposite, entire or dentate, or pinnatifid, obtuse, sessile. Carpels rather 

 short, broad-oblong, dorsally convex, glabrous. 



(Australia and New Zeal.); Falklands, in freshwater lagoons and run- 

 ning streams, abundant. Magellan (R. O. Cunningham); S. Patagon.; 

 Rio Chico ; N. and E. Fuegia. 



2. M. PROSERPINACOIDES Gill. 



Dioecious. Leaves all submersed, similarly pectinate-pinnatifid, 4-5- 

 whorled; their segments 20-25. Pistillate flowers axillary, apetalous; 

 stigmas 4, plumose. Young carpels glabrous. Hair-like bracts among 

 the leaves. 



(Chili; naturalized in parts of N. J., U. S.); N. Patagon. 



3. M. SPICATUM Linn. 



Submerged leaves whorled and dissected. Floral leaves ovate, entire 

 or serrate, shorter than the flowers, or none. Spike about 5 cm. long, 

 like a leafless interrupted spike. Carpels rounded on the back. 



(Eurasia and N. Amer.); S. Patagon.; Valley of Sta. Cruz, by Hatcher. 

 Near the base of the stem many of the submersed leaves are opposite 

 and undivided, linear-acute, 5-nerved ; some of these sending lacinia out 

 from their margins ; and many of them are closely covered with Diatoms. 



