256 ORDERS, GENERA, AND SPECIES. 



1196. Sagittaria sagittifolia, 58 ; F. W. F. vi. 61 ; July 

 20 ; Scotland naturalised, Cumberland to Kent and Devon, 

 Ireland local. p. 128 



1197. Butomus umbdlatus, 60 ; F. W. F. in. 85 ; June 

 18 ; Scotland naturalised, York and Durham southwards, 

 Ireland rare. p. 97 



Order 91. Naiadaceae. Flowers 1-2-sexual ; perianth of 

 scale-like sepals or ; stamens as many as sepals ; 

 fruit of 1-4 carpels ; aquatic herbs with various 

 floating or submerged leaves and inconspicuous 

 flowers. 



1198. Triglochin maritimum, 79 ; May 16 ; Great 

 Britain, Ireland, Channel Islands. p. 53 



1199. Triglochin palustre, 116; June 23; Great 

 Britain, Ireland, Channel Islands. p. 76 



1200. Scheuchzeria palustris, 6 ; July 16 ; rare, Salop, 

 Notts., Chester, York, Perth. p. 132 



1201. Potamogeton natans, 106 ; June 27 ; Great 

 Britain, Ireland, Channel Islands. p. 79 



[There are at least 21 species of Potamogeton found in 

 water in our Islands, besides many sub-species and 

 varieties, and their identification is too difficult a 

 matter for the beginner to attempt.] 



Order 92. Araceae. Stamens indefinite ; perianth ; 

 fruit a berry ; herbs with netted-veined leaves, and 

 flowers on a spadix enclosed in a leafy sheath. 



1202. Arum maculatum, 84; F. W. F. I. 29; April 

 24 ; Caithness southwards, Ireland, Channel Is- 

 lands. P. 29 



1203. Arum italicum, 6 ; June 26 ; very local, Corn- 

 wall to Sussex, Channel Islands. p. 76 



1204. Acorus calamus, 31 ; June 19 ; Scotland and 

 Ireland naturalised, York and Lancaster to Somerset and 

 Sussex^ rare. P- 78 



