Page:The Botany of the Antarctic Voyage.djvu/323

Falklands, etc.] very different nature from what occurs in plants, whose joints indicate an interruption of continuity in a rectilinear organ, as the stems of Equisetum, Casuarina, or Salicornia, or from those which increase by new matter being developed at certain intervals from the apex of the axis of growth, as the trunk of a Palm. In Viscum album, the ramification is truly dichotomous, each internode giving off two opposite ramuli from its apex, between which is a third undeveloped bud ; and in V. salicornioides and Arceutholobium ojcycedri the branching is trichotomous, from both the lateral and terminal branches being developed. Another modification is observable in a singular new genus of Lorantliacece, Eubrachiou mihi, {Viscum ambiguum, H. et A.). The idtimate ramuli of this plant are jointed on the stem and appear not to ramify further, but to bear amenta similar to the bracteate spikes of M. punctulatum, all of which are fertile and caducous, the rainulus elongating and producing year by year new amenta, as the old ones drop away.

The axis of the stem and branches of M. punctulatum is remarkably eccentric, the greater quantity of scalariform tissue being deposited on the under side of these organs, a circumstance arising from the horizontal direction the whole plant assumes. An analogous eccentricity in the position of the medulla in the horizontal branches of coniferous trees is very evident, though not so conspicuous, iu other woody plants whose stems are as slender as those of Myzodendron. The truly amentaceous inflorescence of this plant is common also to Antidaphne, Eubrachion, Lepeostegeres, Blume, Tupeia and others of its congeners, if examined at an early stage. The male flowers are abundant, and the females much rarer in Hermite Island, this preponderance of males was also very marked in the M. bracliystachyum.

Mr. Brown first observed the singular position of the stomata in this species, which are placed one on the apex of each tubercle of the stem, and communicate with the cavity or chamber beneath, the respiratory cavity of some authors. The cells of which the cuticle is composed are so completely incorporated into a uniform integument, that the curved utricles, which bound the mouth of the stoma in most plants, are here hardly apparent, though it is to their presence that the ridge (Plate CVII. bis,f. 6, a) is due. The aperture itself, as seen in f. 5 and 6 of the same Plate, is constricted in the middle, somewhat in the form of an hour-glass, but an opening is generally, perhaps always, left between the adjacent edges of this constriction or diaphragm. The stoma thus expands both outwardly and inwardly into a sort of cup, the outer of which is frequently filled with an opaque mass, and the chambers beneath traversed by filaments of a viscid substance stretching from one wall to the other (f. 5). In the external cavity, when empty, parallel concentric hues may be observed, indicating the compound nature of the walls of the aperture. These stomata are abundant on all surfaces of the young stems and branches, but only on the lower surface of the older and horizontal stems.

Male flowers. These are of the most simple structure, consisting of a solitary curved subclavate peduncle in the axil of each bractea, bearing at its apex a large broad depressed gland, on each side of which an anther is seated, (Plate CIV.f. 3, and 4). There are no traces of a floral envelope. The anther is ovoid, one-celled, opening by a small transverse slit at the apex, and containing a membranous columella, which is the remaining unelaborated tissue from which the pollen is formed, the indication of the anther being originally bilocular, as may