ZOOLOGY AND BOTANY^ MICROSCOPYj ETC. 115 



integument ; these inclose the ovoid nucellus. The germination of the 

 seeds was also followed out, presenting the peculiarity of the almost com- 

 plete suppression of the radicle. 



Latent Vitality of Seeds and Rhizomes.* — Dr. Fritz Miiller writes 

 from Brazil to Dr. F. Ludwig, noting some interesting cases in which seeds 

 or rhizomes must have remained for a long time latent. In a felled wood 

 a variety of Bicmus, seedlings of Mandioc, a conspicuous Caladium, a 

 Dioscorea, &c., sprang up as the results of cultivation twelve years before, 

 though before the ground was recleared there was no trace of them. In 

 another case an individual Gloriosa superba was lost for eight years, during 

 which it must have remained latent. The shades of the wood afford very 

 uniform conditions which favour this retention of life without development. 



yS. Ph.ysiolog'y.f 

 (1) Reproduction. 



Fertilization of the HoUyhock and of Indigofera.t — Contrary to the 

 general opinion, and notwithstanding the size and beauty of the flower, 

 Mr. T. Meehan maintains that the hollyhock is necessarily self-fertilized, 

 and that this self-fertilization is assisted by insects. When insects seat 

 themselves on the open anthers immediately after the opening of the flower, 

 they force a quantity of pollen down into the staminal tube upon the 

 immature stigmas. When the stigmas rise above the mass of anthers and 

 are ready for pollination, they are so entirely covered by this pollen, that 

 it is almost impossible for a grain of foreign pollen to reach them. 



The structure of the flowers of Indigofera Dosua Mr. Meehan regards 

 as specially favourable neither to self-fertilization nor to cross-fertilization ; 

 but the great probability is that in the majority of cases the flowers are 

 self-fertilized. 



Fertilization of Labiatae and Borraginese.§ — Herr E. Loew describes 

 in detail the adaptations to insect fertilization in the flowers of a number of 

 species belonging to these two natural orders. 



The Labiatee are visited chiefly by humble-bees and other bees with a 

 long proboscis ; next in the frequency of their visits come butterflies and 

 flies ; and last, bees with a short proboscis, and insects belonging to other 

 orders. By far the greater number of the species are proterandrous. 

 Further contrivances for preventing self-pollination and for the scattering 

 of the pollen are described. The cause of attraction of insects is the 

 odour of a strongly aromatic essential oil. As regards the history of 

 development of the flowers of the Labiatfe, the author suggests that the 

 primary form is a short-tubed pentamerous corolla with a distinct tendency 

 to zygomorphism, a nectariferous ring beneath the ovary, and a strong 

 tendency to proterandry. 



The Borragine^ agree with the Labiatae in the classes of insects which 

 take the chief part in their fertilization, bees with a short proboscis 

 coming next, and butterflies and flies last of all, the number visited by 

 butterflies being very small. The contrivances for pollination are by no 

 means so numerous as in the Labiatae ; among them may be mentioned the 

 peculiar nature of the inflorescence so constant in the orderj and the 



* Biol. Centralbl., vi. (18S6) pp. 513-4. 



t This subdivibion contains (1) Eeproduction (including the formation of the Embryo 

 and accompanying processes) ; (2) Germination ; (3) Nutrition ; (4) Growth ; (5) Respi- 

 ration ; (6) Movement; and (7) Chemical processes (including Fermentation). 



X Proc. Acad. Nat. Sci. Philad., 1886, pp. 291-4. 



§ Ber. Deutscb. Bot. Gesell., iv. (1886) pp. 113-43, 152-78, 198-9 (3 pis.). 



I 2 



