118 PROCEEDINGS OP THE ACADEMY OP [1885. 



or May, and, after flowering there is no sign of any development 

 in the fruit. The ovarium is, indeed, buried between the closely 

 appressed walls of the bases of the mammae. Here they remain, 

 undiscernible, till just before the next flowering season, when they 

 suddenly emerge, and in a single night apparently stretch out to 

 their full length. All attempts, however, to get at the exact 

 time of development had failed, for the fruit was alwaj^s of full 

 Length. when first observed. In this species, the fruit is about 

 two inches in length, clavate and incurved, and, as they are bright 

 red, and more than double the length of the mammas, and pro- 

 duced in considerable numbers, the effect on a plant where they 

 were wholly absent a few days before, is very striking. This 

 same sudden appearance of the fruit a 3 r ear after the ovaria had 

 been fertilized, has been noticed in Mamillaria Niittalliana, 

 and some Mexican allied species. That the sudden development 

 is the result of an elastic projection, and not of a proper growth, 

 is manifest from the fact that the fruit is mature from its first 

 appearance, has its dark red color, and succulence, and the seeds 

 are perfect in color and size. Growth has to finish, in all fruits, 

 before maturity is reached. A related form of elasticity has 

 already been recorded by him in the Botanical Gazette. He has 

 noted that after the maturity of the fruit of Opuntia Bigelovii 

 the seeds are projected from the apex, and run down the sides of 

 the fruit like lava from a burning mountain. In a letter to the 

 speaker, Dr. Engelmann a short time before his death, referred 

 to this observation as a matter of great importance as explaining 

 a fact for which he had never been able to account, that fruit 

 evidently seed-bearing, had generally been found by him to have 

 no seed when cut open. 



Mr. Median remarked that cases where ovaria, though fertilized, 

 would remain a year without signs of growth, were not unknown. 

 1 ndeed, large numbers of Coniferae, and species of Querent or oak 

 had especially this peculiarity. There was often little or no 

 growth in the fertilized fruit till the second year. 



He knew of no author who had made any mention of this sudden 

 and elastic development in the fruit of the Cacti, though the 

 fact must surely have come within the view of some observers. 

 Pfeiffer, Decandolle, Zuccarini, and other leading writers on Cac- 

 taceae, seldom make any reference at all to the fruit, while Dr. 

 Engelmann, who, of all others, has given us the most of what we 

 do know in reference to this interesting part of the history of this 

 plant, simply says in a few instances that the " fruit matures 

 about the same time with the opening of the Mowers.'' He had 

 however, nearly perceived the fact in one instance. He notices 

 in Plantse Lindheimeriansc that in this very species (he then 

 regarded it as M. applanata) "the scarlet fruit is still persis- 

 tent .and forms an outer circle," while the new flowers are opening; 

 and in the Botany of the Mexican Boundary, p. '.), referring to a 

 eloscly allied species. M. miacantha, lie says: " Fruil ripening 



