246 Transactions.— Botany. 
It appears to be abundant in Hawke’s Bay, at least in one locality. I 
have not found it in Canterbury. 
_ This plant at first sight bears great resemblance to S. dejectum, Bréb., 
and indeed, when seen in end view, is not to be distinguished from that 
plant. But, as Dr. Spencer remarks in his letter to me, the broad junction 
of the segments in side view renders it distinct. Ralfs observes of S. dejec- 
tum that “ its segments are connected either without a band or with a very 
short one:" the expression of Rabenhorst is—“ sinu amplo, acutangulo vel 
obtusangulo;" but no conclusion could be drawn from either phrase that 
the segments of the Enropean plant are so closely and broadly joined 
as those of S. clepsydra. Indeed, Ralfs gives the breadth at constriction of 
B. dejectum as 344, inch, which is much smaller than that of the New Zea- 
land plant. If S. cuspidatum, which differs from S. dejectum chiefly in the 
length of its connecting band, is considered a good species, the same rule 
might well be observed for S. clepsydra. 
S. cuspidatum, Brébisson. (R. XXI.) 
Not common. Two specimens from Canterbury, and a few from 
Hawke’s Bay. 
S. (Didymocladon) fürsiserum, Brébisson. §. (R. XXXIII.) 
Fig. 13. 
The specimens whieh I have seen have all either five or six radiating 
processes in end view. Rabenhorst unites Didymocladon with Staurastrum, 
and says that the plant may have 8-4—6-7-8-9 rays: he omits 5. In all 
my specimens the rays in focus at the extreme end have the other series 
behind them in exact, or almost exact, correspondence with them, as 
shown in my figure. 
For comparison with my D. stella (‘Lrans., vol. xiii., p. 808) see below, 
under that species, in the second part of this paper. 
Only from Hawke's Bay, where it seems to be not uneommon. 
8. Penium, Brébisson. 
P. margaritaceun, Ehrenberg. (R. XXV. and XXXIII.) 
I have specimens which, I think, can be referred to all the three varie- 
ties, a, 3 and y of Ralfs. Rabenhorst unites the two first, and indeed here 
they all occur mingled together. As for the third, the main difference 
between it and the others, in England, appears to be the smaller size of 
its granules. None of my specimens show such large granules as are 
figured by Ralfs, but some are slightly constricted at the middle, while 
others show no constriction. 
I was fortunate enough to find, on one occasion, a large quantity of 
this plant in full conjugation, with attached zygospores : there seems to be 
nothing to distinguish it from the English species. 
