17:5 with the cpr^siile o-f a tpl?. shrubby unnamed species that I have 



examined, v;hich also h^ s no cell-vdngs. I^'uture investige tors should 

 also no+e that the position o"^ the r^lpcentp varies, being sometirces 

 con"f*i ned to the centr=il rxis, r t others more or less on the outer 

 T.raT[ o"^ the cell. 



I^e study of the germination o^ the seeds and subsequent devel- 

 O'^nent o"" the seedljnp-s of various sioecjes of this genus "is a most 

 interesting and fescinating one to the biolop-ist, and v;ill, I 

 believe, nrovide better rnd more complete evidence of evolution 

 thpn can be found in any other Penus of plants. In the animal king- 

 dom the evolution o-f different groups from a one another can be 

 riartly traced by the development of the embryo, and among plants 

 1 do not l^nov of any genus or group of genera in v^hich the" evolu- 

 tion of one group of species from another : nd very, dissimilar 

 group can be so well shovm as by the study of the developxaent of 

 seediini^? o-^ vpriou'; ST>ecles of different sections of 1-esembryan- 

 themuai. K 3. Bro\'Ti 



(To be continued.) 



Mesembrvantheraum and some. new p-enera separated from it. 

 f^erd, Ghron. HI. 70: 207. 19S1. 

 (Continued from page 173.) 



207 Havirip- raised from seeds sent to me from Lr ^-ortolr and by 

 several South African botanists and friends numerous species be- 

 lonrin-^ to m^n^r widely?- different sections of the genus, I find 

 that so far as my observations have yet extended, when the seedlings 

 have developed their cotyledons to the fullest extent (for thejr con- 

 tinue to cfro-'-- until Just before the first pair of true leaves ap- 

 nerr), or rather vrhen they have produced the first ^air of leaves, 

 the seedlinp^s can readily be grouped under three distinct tyres, as 

 folTo--: — 



I. In this type the cot"-ledons resemble those of most dicot^rie- 

 donous seedlinp-s, spreadinp* widely,' and are rather thin or thicken- 

 ed benetth, so that viewed sideways they form s very short and 

 broad obconic body. From betvreen them arises a pair of distinct 

 leaves th.at are quite different in shane and appearance from the 

 cotyledons, as pve also the leaves of the adu.l't nlr-nts, which usu- 

 ally'' nroduce more than one pair annually. This type is represented 

 by Fip:. 84, A-F, pnd to it belong the majority of the known species 

 o^ -Vsembr^Tnthemum. 



II. In this tyre the tv?o cotyl'^-dons are combined into a half- 

 p-lobose \)ody slightly depressed r cross the flattened ton. From this 

 borl"' arises a na5r o-^ half-f^lobose distinct leaves, quite unlike the 

 cotvledon^ry bod-''- in ar^pear^nce, as are also the subseouent leaves 

 made b-T the •^lant of which -^ormplly only a nair is -produced e? ch 

 year, '^is t"""pe is represented by Fi^r, q4 G_H, 



III. The cotyledons of this t3'-pe are the same as in type H., 

 ■•"ut the nev; ffrovrth that succeeds them and all subsequent growths of 

 the •^If'nt consist of a single ovoid bod-"- with a tinj'- orifice like a 

 closed mout^ at its anex, and is ouite unlike the cotyledonarj'' body. 

 Fig. 84, I-L represents this curious type, which is intermediate be- 

 t^"een t-"-T^ps II. end IV. '"hen in the stage shown by J, the seedling 

 h^s much resernbT^nce to an acorn in its cun , the acorn-like part 

 T-^oi'nrf of r r>pietranslucent p-reen and finel"''" tuberculate; viewed 

 under e lens it is really quite attractive'. I'he adult pi- nt is fep- 

 resentefl of n-^tnr-i size of K, from a rough sketc'^ I made of a 



