290 Mr M‘Nab’s Report on Open - Air Vegetation . > 6th , 11th , 13th , and 14th , indicating 36 ° , 38 ° , 42 ° , 41 ° , 39 ° , and 40 ° ; while the six highest were on the 20th , 230 , 27th , 28th , and 30th , indicating 54 , 55 ° , 57 ° , 56 , 58 ° , and 54 ° . The following are some of the conspicuous plants bloom ing in the rock garden : Allium Macnabianum . Gentiana gelida . oreophyllum . Helonias asphodeloides . Androsace lanuginosa . Iris filifolia . Arnebia echioides . Linnæa borealis , American . Arenaria laricifolia . Scotch Aster alpinus albus . Meconopsis nepalensis . Astragalus alpinus . Wallichii . vaginalis . Menziesia polifolia versicolor . Campanula turbinata and Nierembergia rivularis . varieties . Orchis foliosa . Van Houttei . maculata superba . Chrysobactron Hookeri . Oxytropis cyaneus . Cypripedium spectabile . Papaver alpinum aurantiacum . Delphinium Belladonna . Pontentilla alchemilloides . cashmerianum . Primula capitata . Dianthus alpinus . luteola . neglectus . scotica . Dracocephalum grandiflorum . sikkimensis . speciosum . Rosa pyrenaica . Epilobium obcordatum . Saponaria cæspitosa . Eriogonum aureum . Saxifraga , many sorts . Eriophorum alpinum . Sempervivum , many sorts . Erodium Manescavi . Silene alpestris . Fragaria lucida . Veronica rupestris . Galax aphylla . Watsonia splendens . > XXVI . On the Genus Halophila .-- By BAYLEY BALFOUR , Sc.D. , M.B. ( Plates VIII . - XII . ) ( Read July 1878. ) Amongst the plants I collected at Rodriguez when I visited the island , in 1874 , as naturalist accompanying the Transit of Venus ' expedition , are two species of marine Phænogam , both of the Naiadaceous genus Halophila . They occur abundantly in widely extended patches on the reefs surrounding the island . One , H. ovalis ( R. Br . ) Hook . fil . , grows on spots which are just uncovered at full ebb tide ; the other , H. stipulacea ( Forsk . ) Aschs . , prefers localities >