Isoetes] isoetejE. lOO" 



Order VI.— ISOETEJE. 



(The characters of the Order are given at page 19.) 



Genus I.— ISOETES,* X. 



Aquatic plants, usually quite submerged. Leaves linear and thick 

 or subulate, crowded on a short, thick rootstock, dilated and concave- 

 at the base. Sporangia (spore-cases) sessile at the base of the leaves, 

 solitary, membranous, of two kinds; those of the outer leaves 

 containing spherical macrospores, each marked with a transverse 

 raised line, and above it 3 radiating raised lines ; those of the inner 

 leaves filled with minute powdery microspores. 



Leaves 2-4 in. long, very slender, pale- 

 green. Macrospores 6-angled ; mi- 

 crospores obscurely 3-angular 1. L kirkii. 



Leaves very numerous, stout,, dark-green, 

 4-12 in. long. Macrospores globose ; 

 microspores ovoid 2. L alpinus. 



1. I. kirkii, Braun. 



Eootstock 3-lobed. Leaves 10-20, 2-4 in. long, -^ in. diam. at 

 the middle, pale bright-green, nearly transparent, very slender, and 

 tapering to the apex. Sporangium small, globose, 4-celled ; macro- 

 spores small, 6-angled, beset all over with minute unequal tubercles. 



This small species was first desci-ibed by Mr. Kirk in New 

 Zealand, and is figured in "N.Z. Inst. Trans.," vol. ii. p. 106. It 

 appears to be very near /. muelleri, a Queensland species. 



Distribution.— GorAmedi to the North Island of New Zealand, 

 oecuning in lakes at a low level — viz., Lakes Whangape, Waikare, 

 and Wahi, in the Lower Waikato district ; and L. Rotokakahi, in 

 Taupo district. 



2. I. alpinus. Kirk. 



Rootstock 3-lobed. Leaves 20-50, about 6 in. or more long, 

 T«"T2 ^^- diS'in- ^t the middle, rather stout and rigid, dark-green, 

 nearly transparent, base much dilated. Sporangium oblong ^-J in. 

 long, 4-ceiled. Macrospores rather large, globose, perfectly smooth. 

 Microspores ovoid, finely tubercled. 



Distribution. — Confined to the South Island of New Zealand, in 

 lakes at 2,000-3,000 ft. elevation — viz., Lakes Roto Iti, Rotorua, 

 and Guyon, Nelson district ; Lakes Lyndon, Pearson, Grassmere, 

 and Windermere, in Canterbury district. 



This species was described by Mr. Kirk in the " N.Z. Inst. Trans.," 

 vol. vii. p. 377, and is fully figured at p. 368. 



* Gr., laos, and etos, evergreen. 



