254 



THE GUIDE TO NATURE. 



Watershield or Cabomba. A genus of 

 three species, native to the warmer parts 

 of America ; a submerged weak-stemmed 

 plant with finely divided fanshaped leaves 

 and tiny white and yellow flowers, grow- 

 ing in the mud in shallow water and ex- 

 tensively cultivated as an aquarium plant. 

 The species usually to be obtained is 

 Cabomba caroliniana, the hardiest and 

 easiest propagated. C. rosaefolia has a 

 red stalk and darker green, more finely 

 dissected leaves, and C. aquatica is a 

 recently introduced, more robust, tropical 

 species. 



Ditch moss or Anacharis. A moss- 

 like almost universally distributed Ameri- 

 can plant, known by a number of local 

 names and so variable in leaves that a 

 number of species have been founded 

 thereon, bat recently all have been re- 

 ferred to the one species, Anacharis cana- 

 densis. It has a thick jointed stem and 

 leaves of variable length y 2 to i J / 2 inches 

 long, in whorls of 4 and 8 about the 

 weak and branching stems. It grows 

 very rapidly and is a good generator of 

 oxygen, to be found in almost every 

 ditch, pond or stream. A. canadensis 

 gigantca is a recently developed larger 

 aquarium variety generally to be had of 

 dealers. 



Water Milfoil and Parrot's Feath- 

 er. These plants are common in 

 most ponds and not too rapid waters of 

 the middle and southern sections of the 

 United States. Of the former, the weak 

 stems are surrounded by whorls of finely 

 divided bright green vounger and dark 

 green and brown older leaves, growing 

 on a mud or sand bottom and having in- 

 conspicuous white flowerets. The three 

 common species are Myriophyllum spica- 

 tum, M. virticillatum and M. alternifolia. 

 Parrot's feather or Chilian water-milfoil, 

 M. proscrpinacoides, is an introduced, 

 nearly related species which has the ten- 

 dency to grow above the water and whose 

 use in the aquarium is more for ornament 

 than utility. It should never be used in 

 ponds. 



Swamp loosestrife or Ludwigia. A 

 genus of about 25 species of aquatic and 

 semi-aquatic plants native to the warmer 

 parts of the United States; recumbent 

 in shallow water or rooted in swamps 

 and the margins of natural waters. 

 There are nine species in the Eastern 



and Middle States, of which the marsh 

 purslain, Litdzvigia palustris, the globe- 

 fruited Ludwigia, L. glandulosa, and the 

 Alternate-leaved Ludwigia, L. alterni- 

 folia, are the most common and more 

 generally used in the aquarium as they 

 all thrive fairly well submerged, but ex- 

 perienced aquariists prefer the beautiful 

 tropical species, L. mulcrttii, with lance- 

 oblong leaves, bright green on the upper 

 and clear red upon the lower sides, a 

 very graceful and ornamental plant and 

 a fair generator of oxygen. 



Stoneworts. A large family of 

 dainty aquatic plants, all fair oxygena- 

 tors and generally distributed through- 

 out the United States. Of these Nitella 

 is more likely to survive in the aquarium 

 than Chara, though both are nearly re- 

 lated and form the genus Characae. They 

 all have more or less finely divided leaves 

 about weak stems bearing spores and 

 fruitlets either in the axils or in the 

 middle of the slender branching leaves. 

 Nitella gracilis and A r . flexilis have thin 

 hairlike leaves upon delicate flexible 

 stems, and Chara gymnopus and C. 

 crimita more densely clustered and ro- 

 bust leaves and stems. Their growth is 

 very rapid and their appearance in the 

 aquarium interesting. 



Riverweed or Potamogeton. This 

 widely distributed aquatic plant, of which 

 40 species and sub-species have been de- 

 termined, has three or four which are 

 desirable aquarium plants and thrive 

 fairly well, though not as good oxygena- 

 tors as those previously mentioned. The 

 curled-leaved species Potamogeton cris- 

 tas, the clasping-leaved P. perfoliatum 

 and the close-leaved P. densns, are ex- 

 tensively introduced and are prized for 

 their fine colors, languid habits and in- 

 teresting appearance. They are all 

 wholly submerged aquatics which occur 

 abundantly in almost all natural waters, 

 ponds, ditches and streams. 



These are about all the more desirable 

 aquarium plants, a selection of most of 

 which may be either obtained in their 

 natural situations or obtained from 

 dealers. All but Sagittaria and Vallis- 

 neria will grow without roots when set 

 in the sand and pebbles, the mentioned 

 two should be planted in shallow pots 

 containing soil covered with pebbles. 



