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The Quillwort in Aquaria 



AQUA - PET 



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Even to botanists, the IsostacEae, re- 

 gardless of its interesting characteristics, 

 is a comparatively little known group of 

 plants, comprising about fifty species. 

 The generic name Isoetes is said to be 

 derived from two Greek words meaning 

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

 cause of the perennial character of the 

 leaves. While the purpose of this article, 

 primarily, to direct attention to their in- 

 terest as aquarium plants, inasmuch as 

 they are usually ignored or given scant 

 attention in works on the aquarium, it 

 may not be amiss to give a brief descrip- 

 tion which should aid in identification. 



The systematic botanist regards this 

 group as a difficult one. Students of 

 plant life are not by any means agreed 

 as to what constitutes a distinct species 

 of this genus, nor its relationship to other 

 classes of plants. It belongs in that di- 

 vision of the vegetable kingdom called 

 Pteridophyta, which includes the ferns 

 and some other spore-bearing or flower- 

 less plants called the fern allies. In the 

 scale of plant development the pterido- 

 phytes are above the mosses and below 

 flowering plants. Some botanists consider 

 the Quillwort to be related to the Moon- 

 wort and Adders-tongue ferns, around 

 which so much superstition clustered in 

 ancient times, while others aver that its 

 structure indicates a connection with the 

 pines and related plants which are the 

 more primitive forms of flowering plants. 



The quillwort is essentially an upright 

 or spreading rosette of hollow, cylin- 

 drical, pointed leaves of a grasslike or 

 rush-like aspect. The leaves vary in 

 length in the various species from a few 

 inches to two feet, and in number from 



ten to two hundred, or even more, spring- 

 ing from a flat bi-lobed or tri-lobed tuber- 

 like rootstock. The new leaves are pro- 

 duced from the centre of the rosette. 

 The plant reproduces from spores, which 

 are born in a hol 1 owed-out portion of the 

 base of the outer leaves. The quillwort 



The Quillwort 



is heterosporous, that is, bears spores of 

 the two sexes on the same plant, but in 

 different leaves. The female spores are 

 about one-fourth the size of a pinhead 

 and few in number, while the male spores 

 are about one-thousandth of an inch in 

 diameter and very numerous. The spores 

 have an outer coating of silicon, that of 

 the male spore being beautifully sculp- 

 tured. A microscope is, of course, re- 



