326 Transactions. — Botany. 



I. grandi Carr. et Pears, affinis, sed habitu robustiore, 

 foliis et amphigastriis majoribus minus profunde bifidis dis- 

 tincta. 



Hab. Growing in water in large round tufts on the top 

 of a hill at Orepuki, Foveaux Strait ; on the summit of 

 Mount Thompson, one of the spurs of Mount Anglem, 

 Stewart Island, New Zealand (Eobert Brown, in litt., 

 January, 1901). 



The hepatic above described was sent to me by Mr. 

 Eobert Brown, of New Zealand. The specimens sent, 

 although sterile, clearly belonged to Isotachis, a genus 

 which, as Gottsche has remarked (see Carrington and Pear- 

 son, in Proc. Linn. Soc. N.S.W., sec. ser., ii., p. 1012, 

 1888), "is readily recognised by its evenly arranged leaves 

 and stipules, which last so nearly resemble the leaves in 

 size and form that the foliage might almost be called tri- 

 farious." Not being able to identify the plant with any 

 species of Isotachis in the Kew Herbarium, I sent a speci- 

 men to Herr Stephani, who kindly informed me that it was 

 a new species. I am indebted to Herr Stephani for the 

 following note on the affinity of the present plant: "It is 

 very near I. grandis, Carr. et Pears., but that plant has 

 asymmetric leaves, the postical part being more rounded 

 than the antical. It is a particular feature of the New 

 Zealand plant that the leaves and stipules are perfectly 

 symmetric. I. grandis also has the leaves (not always, but 

 often) 3-lobate." 



There is a small specimen of I. grandis (" on wet rocks, 

 Lawson, Blue Mountains, N.S.W.") in the Kew Herb., and in 

 this the largest leaves measure 2 mm. by 1-75 mm. (Carring- 

 ton and Pearson give 1-75 mm. by 1-5 mm.); the stipules 

 measure l - 5 mm. by 1 mm. I. stepkanii, besides having 

 much larger leaves and stipules, differs in the manner in 

 which the apex of these is bipartite. This is seen most 

 clearly in the case of the stipules — in I. grandis the stipule 

 is concave at the base of the sinus, and the sinus is not 

 narrowed towards the base ; in /. stephanii the apex of the 

 stipule is plane, and the shallow sinus is distinctly narrowed 

 downwards. 



EXPLANATION OP PLATE XX. 

 Isotachis stephanii, sp. nov. 



Pig. 1. Part of plant, about natural size (left-hand branch turned 



round to show the stipules). 

 Fig. 2. Leaf (flattened) ; x 17. 

 Fig. 3. Stipule ; x 17. 



Fig. 4. Areolation of leaf towards apex ; x 270. 

 Fig. 5. Areolation of leaf towards ba^e ; x 270. 

 Fig. 6. Transverse sectiou of stem ; x 170. 



