K. M i y a k e, Contribut. to the Fertiliz. and Embryogeny of Abies balsamea. 1 35 



am pleased to express my gratitude to Professor Atkinson for liis 

 helpftil suggestions and imfailing kindness, tlirougliout the entire 

 progress of these studies. 



The striictnre and development of the archegonium. 



The niimber of archegonia in a Single ovule varies from one 

 to foiir, the most frequent number being two. I kept an account 

 of the number of archegonia in about six hundred ovules, and of 

 these about two thirds contained two archegonia, about one-eighth 

 had one archegonium and forty ovules had three archegonia each, 

 while only two cases were met with in which each ovule contained 

 four archegonia. Strasburger ('69) stated that the number of 

 archegonia in a Single ovule of Abies pectinata is usually three. 

 Cavara ('OOj found in the same plant that there are generally two 

 or three archegonia, rarely one and still less coramonly more than 

 three in each ovule. 



The youngest archegonium I was able to study was already of 

 considerable size. One of them is shovii in Fig. 1 . The cytoplasm 

 of the central cell presents a flnely granulär appearance under low 

 power and contains a number of vacuoles. The central cell has 

 a nucleus situated near the apex of the archegonium, and is sm'- 

 rounded by a Single layer of sheath-cells. As it approaches its füll 

 size the vacuoles graclually decrease both in number and in size, 

 and a few so-called proteid-vacuoles begin to appear. The nucleus 

 of the central cell has a prominent nucleolus , and is located near 

 the neck-cells, but not so close to them as is the case in Pinus (Miss 

 Ferguson 'Ol) and PiceaP) (Figs. 6 — 7). A similar location of this 

 nucleus has been observed in Tsuga by Murrill (' 00). 



As the central cell prepares for division the deeply staining 

 granulär substances accumulate near the centre of the nuclear cavity 

 as in the corresponding stages of Tsuga (Murrill '00) and Picea 

 (Fig. 7). The nucleolus soon disappears and the spindle-fibres begin 

 to form from both sides of the nucleus. The spindle is extra-nuclear 

 in origin and the lower pole is mucli more prominent than the 

 Upper one (Fig. 8). I was not able to determine whether a clear 

 com't precedes the formation of the lower spindle as in the case of 

 Pimis and Picea. An accumulation of a dense protoplasmic mass in 

 the lower pole of the spindle as observed by Murrill in Tsuga, has 

 not been found in Ahies. Later stages of the division are shown in 

 Figs. 9—14. The spindle seems to be usually pointed at both ends; 

 the case illustrated in Fig. 9 in which both poles appear somewhat 

 obscure and blunt was only rarely seen. Later a cell-plate is tormed 

 in the middle part of the spindle and the ventral canal-cell is cut 

 otf above, the ^g^ being formed below. 



When division is completed the nucleus of the ventral canal- 

 cell is almost similar to the egg-nucleus both in size and structure. 

 It begins to increase in size soon after its formation, and for some 

 time seems to undergo somewhat similar stages of development to 



*) All references to Picea, unless otherwise stated, are takeu from my 

 vmpublished paper „On the development of tlie sexual organs and fertilization 

 in Picea excelsa'*. 



