266 BULLETIN OF THE BUREAU OF FISHERIES. 



that are deep or shallow, fresh, salt, or brackish. It is also extremely variable in growth 

 habit. Two of its remarkable forms which occur in Lake Cayuga and its environs and 

 which Dudley (1886) describes as a slender form" and a gigantic form** are included in 

 the present investigation of this species. 



P. pectinatiis, the species which is common everywhere, is among the first of the 

 Potamogetons to sprout in the spring, making its appearance early in April. Of such 

 plants which appeared early in the season, over a hundred individual specimens were 

 uprooted to determine the agent of propagation. In all cases these plants developed 

 from tubers which were buried in the mud or sand. Figure 38 shows the general habit 

 of growth from these reproductive structures. The new plant quickly establishes itself 

 by developing simultaneously with shoot formation an extensive subterranean system 

 of stems, which in turn send up leafy shoots in great numbers. By this ramification of 

 the underground stems, P. pcctinatus encroaches upon the soil so effectively as to produce 

 dense patches of growth, to the exclusion, in some cases, of other species of aquatics. 

 The plants bear fruit more or less abundantly, but, in general, tuber formation doubt- 

 less equals or surpasses seed production. 



Tubers of various size occur, the size being dependent, more or less, on the nature 

 of the environment. The largest and finest specimens were found at North Fairhaven 

 in the quiet waters of Sterling Creek, where P. pectinatus forms a part of an equatic 

 meadow renowned for its luxuriance of vegetation. These large tuber-bearing plants 

 grow in the rich, mucky substratum at a depth of 6 to 10 feet in association with 

 Elodea canadensis , Myriophyllum. spkalum, Ceratophyllum demcrsum, Utricularia vulgaris 

 var. .4 mericana, Nymphea advcna and other Potamogetons, such as amplifolius and zoslcri- 

 /olins. In this situation the plants are rapidly propagated from the tubers. On June 

 21 several specimens were collected which illustrate the complete cycle of tuber forma- 

 tion. Plants retained intact the old tubers, the new shoot — a tall, leafy, erect axis 

 bearing in some cases a floral spike — and the new rootstocks bearing tubers. On 

 many plants in this most favorable environment the tubers were greatly in excess of 

 the matured fruits, and often the only reproductive structures. The plant dies down 

 early in autumn. In October attempts were made to collect underground stems to 

 determine, if possible, a perennial habit in this region. Only portions of the rootstock 

 were secured, but in every instance disorganization had progressed to a considerable 

 extent. The appearance of the tuber in the spring, when many of the plants were 

 uprooted and observed with shoots growing from them, indicates a complete and 

 natural separation from the parent stem, probably in the autumn. It may be inferred, 

 then, that the tubers are the only vegetative structures that do survive the unfavorable 

 growing season. 



The slender form described by Dudley (1886) was found still occupying the same 

 region in Cayuga Lake where it was observed by him many years ago. The plants 



a 1007. var. (?) with slender elongated stems ( i to i '^meters) ; nodes remote, as are the whorls of the spike, whose peduncle 



is usually over one-tourth meter long. Leaves lew and slender, plants sometimes proliferous. Near the lighthouse, Cayuga X,. 

 Dr. Robbins "found no parallel for this remarkable form," in his o\%ii observations. Dudley. William R,; The Cayuga Flora. 

 Bull. Cornell Univ. (Science), p. 107. 



b 1008. var. (?) a gigantic form growing in deep water northwest and northeast of the lighthouse. Cayuga L. Not yet 



found in flower or fruit, though examined more or less frequently during 10 years past. It is frequently proliferous, especially if 

 detached. It grows in banks, the plumclike bushy tops reaching the surface of the water. The leaves and sheaths are similar to 

 P. pectinatus. except in length. Dr. Robbins remarked that he had "nothing that comes near to it in length of leaves — usque ad 

 10." Stipules arc usually much shorter than in P. pectinatus. Specimens were obtained in 1S74 from 4 to 5^3 meters long. This 

 form was also noticed by Mr. H. B. Lord, probably somewhat earlier than 1874. Loc. cit. 



