Staurastrum bieneanum, Rabenhorst, forma minor. Plate IV., fig. 36.

Frond small; segments in front-view fusiform, with very wide constriction; in end-view triangular, with deeply concave sides, and rounded, rather tapering, angles; cytioderm punctate, the puncta in transverse lines; edges apparently not perfectly smooth.

Long., 20–25 μ; lat., 15–22 μ.

Hawke's Bay; Wellington; Otaki.

I prefer attaching this plant to Rabenhorst's species (which, indeed, he considered rather a variety of S. orbiculare, but which later authors have considered distinct), instead of erecting it into a separate species on the minute variations which it presents.

Staurastrum sub-amœnum, sp. nov. Plate IV., fig. 37.

Frond small, slightly variable in size; constriction only a minute notch. Segments in front-view unequally pentagonal, the sides obscurely sinuous and widening from the base to the sub-acute lateral angles, thence tapering rapidly to the terminal angles; ends straight. The edges all round are obscurely irregular. Within the border the edges of the side-view can be seen. Cytioderm punctate; puncta in concentric curves. In side-view the segments are lozenge-shaped, the angles slightly truncate; edge irregular; puncta in longitudinal series, and the edge of the front-view is visible. In end-view the frond is four-sided, the angles slightly truncate, sides slightly concave, puncta transverse.

Long., 35–39 μ; lat., 28–33 μ.

Hawke's Bay.

This plant belongs to the series of S. capitulum, Brébisson, and S. amœnum, Hilse, of which Professor Nordstedt reports a variety, “tumidiusculum,” from New Zealand. It is, however, less ornate than any of these, and also smaller. S. meriani, Reinsch (as figured by Wolle, “Desm. of U.S.”) also approaches it.

Staurastrum alternans, Brébisson, var. sub-alternans, var. nov. Plate IV., fig. 38.

Frond small; segments in front-view sub-elliptical; when viewed slightly tilted (as in the figure) the third angles of the two segments are not exactly opposite. In end-view, segments triangular, sides concave, angles rounded; the frond being only slightly twisted, the angles of each segment are neither quite in correspondence nor quite alternate. Cytioderm punctate, the puncta transverse.

Long., 25 μ; lat., 26.7 μ.

Christchurch; Hawke's Bay.

I have proposed this as a true “variety” of the original form, as in all the specimens seen since 1879 (perhaps more than a hundred) the twisting of the frond, although distinct, is never sufficient to bring the angles in end-view regularly alternate as in the European and American types.

Staurastrum striolatum, Naegeli, var. acutius, var. nov. Plate IV., fig. 39.

Angles, both in front- and end-views, a good deal sharper than in the type.

Long., 21 μ; lat., 23 μ.

Hawke's Bay.

Staurastrum ventricosum, sp. nov. Plate IV., fig. 40.

Frond moderate; constriction deep and wide; segments in front view elliptico-fusiform, with convex ends, and prolonged into short processes each tipped with three minute spines; cytioderm rough with conspicuous granules; on the outer edges several spines, small, simple, neither dilated nor forked. End-view triangular; processes short; edges obscurely irregular; sides slightly concave; granules in transverse series.

Long., 39 μ; lat., 40 μ.

Christchurch; Wellington; Kaitoke; Hawke's Bay.

A plant which I had at first considered as a variety of S. proboscideum, Brébisson; but it is separated from that species by the absence of forked or dilated spines, and by the transverse arrangement of the granules in end-view. It is much smaller than the next species, and has not concave or depressed ends with widely divergent spines in front-view.

Staurastrum splendidum, sp. nov. Plate IV., fig. 41.

Frond rather large; constriction wide. Segments in front-view sub-orbicular, the ends depressed or sometimes slightly concave, sides produced into moderately long processes, each bearing three conspicuous spines. Cytioderm rough with large conspicuous granules. Edge smooth, or obscurely irregular for a little way from the isthmus, thence conspicuously crenulated to the commencement of the depressed ends; between the crenulations conspicuous simple spines inclined outwards. End-view triangular; cytioderm rough with granules arranged transversely; sides slightly concave; edges crenulate, with simple spines; angles truncate, tricuspid; viewed from the isthmus the orbicular form of the segment is conspicuous.

Long., 67 μ; lat., 52 μ.

Christchurch; Hawke's Bay.

This is the plant which in my paper of 1882 I wrongly considered as a form of S. aculeatum, Ehr. Mr. W. B. Turner tells me that he thinks it is intermediate between the smaller

forms of S. sebaldi, Reinsch, and S. proboscideum, Brébisson, The large, simple spines, and the straight or concave endsr seem to separate it from either; and the spines are not sufficiently long nor the segments slender enough for S. aculeatum. The two forms reported from New Zealand by Professor Nordstedt—S. sebaldi, β ornatum, var. novizelandica; and S. pseudosebaldi, var, tonsum—differ from it in several particulars, both being much more slender, and the last not having a triangular end-view. The large size, the depressed ends, and the conspicuous spines on the edge in end-view distinguish it from the last species.

Staurastrum pileatum, Delponte, var. inflatum, var. nov. Plate IV., fig. 42.

Frond moderate; constriction shallow and wide. Segments in front-view sub-trapezoidal, widest outwardly; sides and ends slightly convex; outer angles terminated by two rather thick spines; cytioderm smooth or very obscurely punctate in the middle, and bearing five or six transverse rows of granules towards the angles; edges obscurely irregular. End-view triangular; sides very slightly concave, angles slightly inflated and terminating in spines; granules in transverse rows near the angles only; edges smooth except by the rows of granules.

Long., 45 μ; lat., 60 μ.

Otaki.

This plant appears to differ from Delponte's species (“Desm. Subalpin.,” p. 167) in the more convex form both in front-and side-views.

Staurastrum pseudoligacanthum, sp. nov. Plate V., fig. 43.

Frond moderate; constriction deep, linear; segments in front-view sub-quadrate, but produced at the sides to sub-acute angles so as to have an irregularly pentagonal form; sides sinuous, ends straight; cytioderm smooth in the median space, and bearing towards the angles a few transverse rows of minute puncta; edges obscurely irregular or crenulate, and bearing between the lateral angles and the straight ends four or five spines, of which two at each side are conspicuous; the spines of the third angle are visible on the face of the frond. End-view triangular; sides straight, edges obscurely irregular; on each side are two spines dividing it in three equal divisions; cytioderm bearing transverse rows of puncta towards the angles, and three pairs of granules corresponding to the six marginal spines.

Long., 35.9 μ; lat., 37.9 μ.

Otaki.

The figure of S. oligacanthum, Bréb., given by Nordstedt (“Desm. Arctoæ pl. vi), differs from the above in a few

particulars, mainly in the arrangement of the spines. The triangular end-view of our species is scarcely a distinctive character, as so many of the Staurastra seem to have indifferently three or four sides.

Staurastrum spinuliferum, sp. nov. Plate V.,fig. 44.

Frond moderate; constriction shallow, wide; segments in end-view inflato-fusiform, widening rapidly from the isthmus to the angles; ends convex; angles acute; cytioderm bearing minute puncta arranged in transverse rows, and towards the angles very minute spines; many very minute spines along the edges all round, and at each angle three spines rather larger. End-view triangular; sides straight or slightly concave; cytioderm punctate; spines as in front-view.

Long., 34 μ; lat., 26.9 μ.

Hawke's Bay.

Probably of the series of which S. hirsutum, Ehr., is the type; but it differs in its acutely-angled front-view from all, and the spines are also much smaller than in any species described. Indeed, only careful examination will detect them. I have stated above that in front-view these spines are noticeable on the surface towards the angles, the median space being simply punctate: it may be that the spines cover the whole frond, but they are too minute to be made out. Mr. Turner suggests that the plant may be a form of S. kjellmanni, Wille, which has minute conical granules on the edge; but in our species they are certainly fine spines.

Staurastrum pseudassurgens, sp. nov. Plate V., fig. 45.

Segments in front view widely dilated from a rather narrow isthmus, with gaping constriction; lower edges very slightly crenulate, outer edge crenulate, convex, with a series of minute granular verrucæ just within the edge; segments produced at each side into sub-cylindrical processes, each of which curves gradually but conspicuously upwards, and ends in two rather large teeth, widely diverging, one tooth turned well upwards, the other usually horizontal or nearly so. End-view fusiform, slender, the median portion slightly dilated, the rows of verrucæ visible; two terminal teeth usually visible, but often only one. Zygospore sub-globose with concave edges, bearing a number of long rays which are forked and recurved at the apex.

Long., 29–32 μ; lat., 46–50 μ; diam. zyg. ex rad., 27 μ; long. rad., 12 μ.

Rutherford's Swamp, Otaki.

I at first considered this plant as S. assurgens, Nordstedt, having then only a sketch of the latter. I find, however, that it differs, first in size, secondly in less slender shape, thirdly in never exhibiting more than two teeth on each process. In

general appearance it approaches S. bicorne, Hauptfleisch (apud Lagerheim in lit. cum icone); but that plant has deep quadrangular crenulations on the edge in front-view, which are absent from our species. The zygospore resembles somewhat that of S. sagittarium, Ndst. (“Alg. of N.Z.,” p. 37), but is much smaller and less angular.

Staurastrum inconspicuum, Nordstedt, forma gracilior. Plate V., fig. 46.

Frond very minute; in front-view sub-rectangular, the constriction represented by concave sides, and the angles produced into short sub-cylindrical processes slightly bent in the middle and obscurely forked at the tip; two of these processes can be seen in focus at once at each end, and a third is seen either in front or behind, between each pair. End-view convexo-triangular, the angles produced in processes alternating with the three processes of the other end, which may be seen between them. Length of the frond in front-view more than twice the diameter at the isthmus.

Long. ex rad., 11.7 μ; lat., 9 μ; lat. isthmi, 4.3 μ; long. rad., 4 μ.

Otaki.

This form is more slender than Nordstedt's original plant, and rather smaller; and the specimens which I have observed are triangular in end-view, the American and European forms being quadrangular. Probably forms may exist here with either three or four sides.

Staurastrum furcatum, Ehrenberg, forma? Plate V., fig. 47.

I have only one specimen of this plant, and have not seen it in end-view: it is referred therefore here only provisionally to Ehrenberg's species. It is the one which in my paper of 1882 I considered as probably S. spinosum of Ralfs, which several authors (e.g., Rabenhorst and Wolle) refer to S. furcatum. The species appears to be very variable: my figure approaches that of Wolle (“Desm. of U.S.,” pl. xlviii.), especially in the occurrence of a process or processes on the frond near the isthmus.

Long. ex rad., 26.7 μ; lat., 16.4 μ; long. rad. circ., 5.5 μ. Hawke's Bay.

Staurastrum brachiatum, Ralfs, var. gracilius, var. nov. Plate V., fig. 48.

Frond extremely minute; constriction only a small notch; segments in front-view sub-quadrate, produced at the outer angles into long, sub-cylindrical, smooth, very transparent processes, which are deeply cut into two or three (mostly three) points; endochrome extending only to the quadrate