210 



JUNCAG1NACE/E. 



[Endogens. 



Order LXVI. JUNCAGINACE.fi.— Arrow-grasses. 



Juncaginea,, Rich. Anal. Fr. (1808) ; Mem. Mus. 1. 364. (1815) ; Endl. Gen p. 127 ; Meisner, p. 364; 



Kunth Emm. 3. 141.— Fotamogetonese, Rchb. Fl. Excurs. 1. 6. (1830). 



Diagnosis.— A lismal Endogens with scaly flowers, few-seeded simple axile or basal 



placentas, and an embryo slit on one side, with a very large plumule. 



Herbaceous aquatic or marsh plants, whose leaves have in all cases parallel veins, 



whether they are narrow and grassy, or broad and quite different from the leaf-stalk. 



3 



^ 



1 



CXLIII. 



Fig. CXLII. 



Flowers , of no conspicuous appearance, white or green, in spikes or 

 racemes. Sepals and petals small and much alike. Stamens 6 ; anthers 

 usually turned outwards and opening longitudinally. Carpels 3, 4, or 6, 

 free, united or distinct ; ovules 1 or 2, approximated at their base, erect 

 or pendulous. Fruit dry, 1- or 2-seeded. Albumen wanting ; embryo 

 having the same direction as the seed, with a lateral cleft for the emis- 

 sion of the plumule. 



With the exception of their flowers being Q , there is little to separate 

 these plants from the Naiads, in whose Order some of them have been 

 included by all botanists before this time ; for the old distinction of 

 pendulous ovules in the Naiads, and erect ones in Arrow-grasses, fails 

 in consequence of Caulinia, and Naias itself, having them erect. The 

 plumule lying within a cleft on one side of the embryo indicates a decided 

 tendency on the part of these plants to Arads, and the incomplete con- 

 dition of their floral envelopes confirms the relationship. The genus 

 Scheuchzeria is a transition from Arrow-grasses to Rushes. 



Marshy places in most parts of the world may be expected to indicate 

 traces of this Order, which is found in Em-ope, Asia, and North America, 

 the Cape of Good Hope, and equinoctial America. Potamogetons occur 

 in ditches and swamps as far north as Iceland. 



Triglochin has a salt taste. The root of Potamogeton natans is said 

 to be eaten in Siberia ; the foliage of others is regarded as styptic. 



GENERA. 



Triglochin, Linn. 

 Juncayo, Tournef. 

 Tristemon, Raf. 



I Scheuchzeria, Linn. 



I Ruppia, L. 



I Potamogeton, L. 



Peltnpsis, Raf. 

 Aponogeton, L. 

 Spathium, Lour. 



Numbers. Gen. 7. Sp. 44. 



ICycnogeton, Endl. 



Ouvirandra, Thouars. 

 \ Hydrogeton, Pers. 



Limnogeton, Edgw. 



OSITION.' 



Naiadaceee. 

 -Juncaginace^e. — Alismacese. 

 Juncacece.- 



Pta CXLII.— 1 Leaf of Ouvirandra fenestralis ; 2. a flower cut open; 3. section of a ripe carpel 

 of O Bernieriana j 4, 5. embryo in different positions : the thicker part is the cotyledon, the smaller the 



rll Ki R Ul rXLIU. -Triglochin palustre. 1. A flower: 3. a ripe fruit; 4. one ripe carpel opened, and 

 exhibiting a seed ; 5. embryo. 



