ISOETES JAPOKICA, A. BE. 



8 



67 



Group 2. Terrestres. 



Leaves with narrow lacuuse, the outer wall of which consists of only one 

 layer of cells. Stomata numerous. 



Only 4 groups of hypodermal fibres present. Phyllopodes present, with or 

 without spines ; tlie phyllades forming a scale. 



3. Baker (i, p. 124). 

 Group 1. Aquaticse. 



Plants permanently submerged. Leaves without stomata, groups of hypo- 

 dermal fibres,' or phyllopodes. 

 Group 2. Subaquatic^e. 



Plants inhabiting sli allow water. Leaves with few stomata, but without 

 groups of hypodermal fibres. Phyllopodes absent. 

 Group 3. Amphibise. 



Plants inhabiting shallow water, where they are subjected to desiccation 

 during certain periods of the year. Leaves with groups of hypodermal fibres ; 

 stomata abundant. Membranous leaf-bases occasionally persistent. 

 Group 4. Terrestres. 



Plants growing in damp or water-logged soil. Leaves with groups of hypo- 

 dermal fibres ; stomata abundant. Phyllopodes present. 



4 Eaton (13, pp. 58, 59)*. 



1. Aquaticae, A. Br. 



Plants submerged ; leaves cylindrical, fleshy, without groups of hypodermal 



fibres or stomata. 



2. Amphibia?, A. Br. 



Plants of inundated shores or tidal flats; leaves with stomata, but without 



groups of hypodermal fibres. 

 § 3. Palustres, A.. A. Eaton. 



Plants inhabiting the extreme edge of ponds or streams ; leaves with stomata 



and groups of hypodermal fibres. 



§ 4. Terrestres, A. Br. 



Plants inhabiting dry situations ; leaves setaceous with numerous stomata 



and 4 groups of hypodermal fibres ; velum absent. 

 Usino^ the above classifications it would be very difficult to determine the section in 



o 



which I. japonica should be included. For instance, this species may grow in situations 

 where the plant is always completely submerged, or it may grow on damp soil at least 

 for a short period. On the one hand, it produces leaves devoid of both stomata and 

 hypodermal fibres ; on the other hand, the leaves are provided with both fibres and 

 stomata or with groups of fibres alone f. Thus one and the same species may belong to 

 Aquaticae " of A. Braun and of Baker, to " Submersse " of Motelay and Vendryes, 

 ) " Amphibise " of A. Braun and of Baker, and to '* Palustres "of Motelay and Vendryes 

 ad of Eaton. 



a 



* Includes North-American species only. 



t It is possible that specimons may be found with stomata but without groups of fibres. 



'ECOND SERIES. — ^BOTANY, VOL. VIII. 



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