December 14, 190G.] 



SCIENCE. 



771 



suggestion of Noel Bernard {Rev. gen. d. Bot. 

 14: 139, 269. 1902), and of Jvimelle {Rev. 

 gen. d. Bot. 17: 49, 1905), that potato tubers 

 are caused by a fungus, a species of Fusarium, 

 endotrophic with S. tuberosum. 



In the normal formation of tubers two kinds 

 of factors are doubtless involved: the first 

 organic, consisting of specific peculiarities in 

 the protoplasts; the second environmental, 

 comprising external conditions, especially of 

 light and moisture, and the stimulus of the 

 various metabolic products within the stem. 

 The ability to induce tuberization in aerial 

 stems by depriving them of light and reducing 

 their transpiration, as Vochting did, and the 

 sport described by Yilmorin {Torreya, I. c), 

 suggest that the specific cellular peculiarities 

 obtain throughout the entire shoot system, 

 and need only the stimulus of definite en- 

 vironmental conditions, either external or in- 

 ternal, to make them operative. 



In this connection it would be desirable to 

 know whether the presence, in any portion of 

 the potato stem, of a superabundance of food 

 materials would operate as a stimulus, causing 

 the excessive formation of parenchymatous 

 cells, which, gorged with the reserve food, 

 make up the greater part of the bulk of the 

 tubers. It is well known, through the re- 

 searches of Knight and others, that, if the 

 flow of food materials is diverted from in- 

 cipient underground tubers by removing them 

 as fast as they begin to form, this material 

 will accumulate in portions of the aerial stem, 

 causing tubers there. In the specimen in 

 question, translocation of digested food be- 

 came established toward and into the develop- 

 ing ' sprouts,' but elongation of the latter was 

 not favored because of the very slight water- 

 supply from without. It does not seem im- 

 probable that a combination of these two con- 

 ditions alone would be sufficient to produce 

 the tuber, even in daylight. 



Two New Coralline Algce from Culehra, Porto 



Rico: Dr. Marshall A. Howe. 



Dr. Howe exhibited and discussed briefly 

 specimens representing two rather large and 

 conspicuous kinds of non-articulated corallines 

 which were secured during a visit made last 

 March to the island of Culebra. These have 



been studied in collaboration with Dr. M. 

 Foslie, of Trondhjem, Norway, and a joint 

 paper, in which the two new species are to be 

 described and illustrated, is soon to be pub- 

 lished. One of the species is a Ooniolithon 

 which seems to have its closest affinity among 

 the forms already described in a species orig- 

 inally found on the island of Funafuti, of the 

 Ellice Islands group, in the South Pacific. 

 The second species, a Lithophyllum which 

 forms columnar flat-topped masses sometimes 

 a foot in height, is evidently a reef-builder 

 at Culebra, and, like the other, curiously 

 enough, finds its nearest relative in a species 

 originally described from Funafuti and since 

 reported from the Maldives in the Indian 

 Ocean. The speaker remarked upon some of 

 the general characteristics of the non-articu- 

 lated corallines, and showed microtome sec- 

 tions and photomicrographs illustrating the 

 structure of the two species that were under 

 discussion. In reply to a question as to the 

 ecological relationships of the coralline algae 

 and the true corals, it was stated that though 

 certain species of both groups are reef-build- 

 ers and inhabit similar places, each of the 

 groups seems to be somewhat inimical to the 

 other. A place in which corals are flourishing 

 is not a good place in which to look for coral- 

 line algse, and vice versa. It is a common 

 thing to find corallines attached to dead or 

 moribund corals, but comparatively rare to 

 find the corals growing on calcareous algse. 

 In one case a crustaceous coralline was noticed 

 to be encroaching upon and covering a living 

 coral. 



RemarJcs on the Flora of Nova Scotia: Dr. C. 



B. EOBINSON. 



The province of Nova Scotia consists of a 

 peninsula connected with New Brunswick by 

 an isthmus of very slight elevation, and the 

 island of Cape Breton separated from the rest 

 of the province by the Strait of Canso, which 

 at the narrowest place is less than a mile 

 broad. The northern part of the island is 

 composed of hills between 800 and 1,400 feet 

 high, except narrow strips along the coast and 

 in the river valleys. 



In general the flora of the peninsula and 

 island is composed of plants which have mi- 



