igig] DUPLER—TAXUS 363 



2. The sporophyll primordia first appear as slightly rounded 

 lobes above the general surface and may arise in acropetal 

 succession. 



3. The archesporial initials are hypodermal cells and develop 

 according to the eusporangiate method. There are 4-8 of them, 

 distributed around the margin of the primordium. 



4. The sporogenous tissue reaches the mother cell stage about 

 October i, and forms microspores about 2 weeks later. There is 

 no abortion of sporangia such as occurs in Torreya, the sporangia 

 occurring in a circle around the stalk of the sporophyll. 



5. The sporangium wall is usually 2-layered. The tapetum 

 arises from the peripheral layer of the sporogenous tissue and 

 persists until after megaspore formation. 



6. The epidermis of the sporangium remains alive and thin- 

 walled at the base, dehiscence being accomplished by the rupture 

 of these cells at maturity, by the elongation of the stalk of 

 the sporophyll. Owing to the disintegration of the sporangium 

 wall, the epidermis is the functional wall in the later stages. 



7. The strobilus matures the latter part of April. Just before 

 maturity there is an enlargement and elongation of the axis, 

 pushing the sporophylls beyond the scales. 



8. The strobili of Taxus canadensis are somewhat smaller than 

 those of T. baccata. 



9. The strobilus bundles are collateral endarch, excepting in the 

 terminal portions of the scale bundles and the sporophyll bundles, 

 where they may be mesarch, and in the latter show indications of 

 occasional exarch structure, the terminal portion of these bundles 

 also being concentric. 



Huntington, Pa. 



LITERATURE CITED 



1. Arnoldi, W., Beitrage zur Morphologic der Gymnospermen. III. 

 Embryogenie von Cf/'/m^''^^-^"'^^^''^""^'- Flora 87:46-63. pis. 1-3. 1900. 



2. Celakovsky, L., Die Gymnospermen: einemorphologisch-phylogenetische 

 Studie. Abhandl. Konigl. Bohm. Gesell. Wiss. VII. 4:1-48. 1890. 



3. Chamberlain, C. J., Winter characters of certain sporangia. Box. Gaz. 

 25:125-128. pi. II. 1898. 



4. CoKER, W. C, On the gametophytes and embryo of Taxodium. BoT. 

 Gaz. 36:1-27, 1 14-140. pis. i-rii. 1903. 



