THE AQUARIUM 



Issued in the Interests of the Study, 

 Care and Breeding of Aquatic Life 



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Vol. I SEPTEMBER, 1912 No. 4 



Aquatic Plants Worth Cultivating 



(CoNCIl'DKI)) 



\V. A. POYSER, Chicago 



?>. The QriLLwoRT as an Aquarium 

 Plant. 



Even to botanists the Isoetaceae, re- 

 gardless of its interesting eliaracterisies, is 

 a comparatively little known group of 

 plants comprising about fifty species. The 

 generic name Isoetes is said to be de- 

 rived from two Greek words meaning 

 "equal" and "year" and was applied be- 

 cause of the jxrennial eh;iracter of the 

 leaves. While the pur];)ose of this article 

 is, primarily, to direct attention to their 

 interest as aquarium })lants, inasmuch as 

 they arc usually ignored or given scant 

 attention in works on the aquarium, it may 

 not be amiss to give a brief description 

 from a botanical point of view which 

 should aid in identification. 



The systematic botanist regards this 

 grou]) as a difficult one. Students of 

 l)lant life are not by any means agreed as 

 to what constitutes a distinct species in 

 this family, nor its relationship to other 

 classes of plants. They belong in that 

 division of the Vegetable Kingdom called 

 "Pterido])hyta," which includes the ferns 

 and some other spore-bearing or flowerless 



plants called the fern allies. In the scale 

 of plant development the pteridophytes lie 

 above the mosses and below the flowering 

 plants. Some botanists consider the Iso- 

 etes to be related to the Moonwort and 

 Adderstongue ferns, around which so 

 much superstition gathered in ancient 

 times, while others consider that their 

 structure indicates a connection with the 

 pines and related plants which are the 

 more primitive forms of the sub-kingdom 

 of flowering plants. The Isoetes, or to use 

 its comon name, quillwort, is essentially 

 an upright or spreading rosette of hollow 

 cylindrical pointed leaves of a grass-like 

 or rusli-like aspect. The leaves vary in 

 length in the various sjiecies from a few 

 inches to two feet, and in number from 

 ten to two hundred or even more, 

 springing from a flat bi-lobed or tri- 

 lobed tuber-like root-stock. The new 

 leaves are produced from the centre 

 of the rosette. The plant reproduces 

 from spores which are born in a hol- 

 lowed-out portion of the base of the 

 outer leaves. The quillwort is heterospor- 

 ous, that is, bears spores of the two sexes 

 on the same plant but in different leaves. 

 The megaspores or female spores are 

 about one-fourth the size of a pin-head and 

 few in number, while the male or micro- 

 spores are about one-thousandth of an inch 

 long and very numerous. The spores have 

 an outer coat of silicon, that of the mega- 

 spore being beautifully sculptured. A 

 microscope is, of course, required to see 

 the markings. Much stress is laid on this 

 marking in distinguishing the various spe- 

 cies. The quillwort occurs growing in sand, 

 mud and gravel on the bottom and banks of 

 streams and lakes. A great many spe- 

 cies are always submerged, while others are 

 only jiartially so, or are terrestrial. Enough 

 for the botanical phase of the subject. 



While the adaptability of the quillwort 

 to the purposes of the aquarist is not as 

 broad as many other easily obtainable 



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