The Botany of the Antarctic Voyage/Part I/Pozoa reniformis
1. Pozoa reniformis, Hook, fil.; foliis longe petiolatis reniformibus multilobatis lobis latis retusis, petiolis basi vaginantibus, pedunculis petiolo brevioribus, involucri foliolis 3–4 linearibus, pedicellis 5–7 brevibus, calycis lobis late ovatis obtusis. (Tab. XI.)
Hab. Lord Auckland's group; clefts of rocks and amongst stones on the hills, alt. 1400 feet.
Herba pusilla, glaberrima, carnosa, facie Hydrocotylis, graveolens. Caulis crassitie pennæ passerinæ, longe repens, articulatus, nodosus, ad nodos cicatricatus, apice foliosus. Folia ½–¾ unc. lata, exacte reniformia, luride viridia, nitentia, radiatim venosa, lobis late rotundatis. Petioli 2–3 unciales; vaginis basi magnis latis, superne acutis. Pedunculi ex axillis fohorum, breves, semipollicares. Pedicelli vix 2 lin. longi. Petala parva, obovata, subacuta, medio late uninervia. Stylopodia superne truncata. Fructus oblongus, tetragonus; mericarpiis demum dorso canaliculatis.
A decidedly extra-tropical South American form, belonging to a section of the Nat. Ord. hitherto unknown to the Floras both of New Zealand and Australia. The remarkable similarity of the flower and fruit to those of the P. coriacea, Lag. (Hook. Bot. Misc. vol. i. p. 331. t. 66), together with the uniformity in the structure of its calyx and petals with that plant, have induced me to refer it to the same genus; but, from the difference in habit and the structure of the involucre of the species thus brought together, I have ventured to place this in a separate subgenus. The original species (P. coriacea), and the P. hydrocotylifolia, Bridges and Fielding (Sertum Plant, t. 40), have the flowers monœcious, a character I do not observe in this. The similarity which the present plant bears to the genus Azorella, Gaud., is in many respects close; the mericarps of this are hardly "parallelim biscutata," whilst those of Azorella are scarcely didymous. Though a very remarkable habit runs through most of the species of the latter genus, one of them, the A. Ranunculus, D'Urv., not only differs from its congeners in form and mode of growth, but in these respects much resembles this plant. In the structure of the flower and fruit they totally differ, the former being truly an Azorella, and having the ciliated involucral leaves common to other species of that genus. The Az. daucoides, D'Urv. Fl. Ins. Mal. l.c. p. 613, is probably a true Caldasia, Lag.
Plate XI. fig. 1, flower; fig. 2, flower with the petals removed; fig. 3, petal; fig. 4, ripe fruit; fig. 5, transverse section of the same; fig. 6, front, and fig. 7, back view of seed; fig. 8, vertical section of the same showing the embryo; fig. 9, embryo removed:—all more or less magnified.