niigE 
pyzomaea I find the structure of the leaf gsreatly divergent from 
No. 5091,the epidermis cells not broader but shorter, and that 
unusually short,1 - 2 times or a maximum of 3 times as long as 
broad, with No. 5091 however LK - 6 times as long as broad.Even 
the cells supporting the parenchyma very rich in chlorophyll,and 
absolutely no stomata.Thus I assume that you investigated leaves 
of the other number of the large form, which perhaps belongs to 
a larzeer form of pygmaea, or possible belonges to a third species. 
Differences in the veil,which I believed to have found after 
examining only 1 - 2 leaves, may be indeterminate, however the 
spores are different beyond doubt, as those of pygmaea have lots 
of small, separate, roundish and rather pointed minute holes, 
which only rarely are elongated root-like, whereas number 5091 
has many root-like,elongatedelevations, very low but distinct. 
I found microspores only for pygmaea, short,plate-like,but like 
Engelmanni var. valida.As to the size of the MAOTOBSparaBE find 
that my measurenments result in all cases to be larger than yours; 
it is probable that my observations are not quite exact and I 
shall correct my measurements in the future a little downward. 
I find the macrospores of No. 5091 with a diameter of 0.40 - 
0.45 mm up to 0.48,those of pygmaea of very uneven size, but 
on averaze larger than the preceding.I find then 0.36 - 0.60 mm. 
I cannot believe that my form of Isoetes,which certainly does 
not have any stomata,could be specifically idenrtical with one, 
which definitely has stomata. I believe that despite undeniable 
relationship these 2 forms must be kept specifivally separate, 
as with I. echinospora and ambigsua. Please send me something of 
the missing number! 
On the same day on which your letter arrived I received a 
rich package from Durien. Besides Characeae of Isoetes a strange 
6 7 8 9 10 MIıSSOURI 
. BOTANICAL 
eleJe)igtelai e-II-1@17-Te GARDEN 
