1886. ] BOTANICAL GAZETTE. 117 
dry woods, from Michigan to Long Island, and Pennsylvania to North Caro- 
lina. 
Easily distinguished from E. Pennsylvanica by the slender culms and pan- 
icles, the very short cauline leaves, the longer and wider lower glume, the more 
obtuse and shorter upper glume, and the shorter obtuser flowering glumes. 
A FILIFORMIS—E. Pennsylvanica, var. filiformis Chapman. Very 
easily distinguished ‘by the very long filiform leaves, slender culm and panicle, 
short obtuse flowers, and very obtuse smoothish upper glume. Florida to Texas. 
ere are several varieties of E. Pennsylvanica and of E. obtusata, and in 
Douidtansd there is a peculiar form with often 3-flowered spikelets, the flower- 
ing glumes acuminate and sometimes mucronate.—GEo, VASEY. 
n the characters of species in Caeti.—Just what are good characters or 
not for distinguishing species of Cactacee is worthy of study. As the s 
are so difficult to determine in herbaria, I try to get living specimens and watch 
their growth. Some two years ago I had sent to me by a stranger in Texas a 
plant which he called Mammillaria applanata, with a hint that if I sent money 
and trusted to him, he would send living plants of the cacti of that region to 
the value thereof. I sent five dollars, but have never had cactuses, or answers 
to letters since. Though my plant, therefore, cost me five dollars, it seemed to 
agree pretty well with Engelmann’s description in Pl. Lindheimeriana, of M. ap- 
planata. Haage & Schmidt of Erfurt, in the midst of men who know cacti, 
sent me another as M. applanata. Dr. Engelmann, in Botany of Mexican Bownd- 
ferent forms” of M. Heyderi, Muhlenpf. Now M. applanata, as described by 
Engelmann, is “ depressed,” with yellowish lobes to the stigma, and yellowish 
stamens. M. hemispherica is “hemispherical,” with yellowish-red stigma- 
lobes, and reddish stamens. Now this last suits my German specimen, and it 
should be that “ form,” but Engelmann says it has much fewer and shorter 
spines than the “form” applanata; but this has just as many and just as long, 
but they are so slender that they might be termed cilia, and they are slightly 
recurved. The other, which being depressed might be applanata, has stiff and 
rather lighter spines. The plant is about three inches high by four wide; the 
hemispherical one about four by six. The tubercles in the depressed one are 
so close together that we can note no fleecy wool in the axils, while in the other 
they are all distinct, and the little mass of wool is plainly seen. In the de- 
pressed form the flowers are so comparatively short that they can not expand 
fully, through the interference of the spines; in the other they are longer, so 
long that the petals spread over the bundles of spines, and when in full sunlight 
give the plant quite a gay appearance. So far as we usually judge of species 
among cacti, we have characters for two good species. Outside of this are 
characters not mentioned by Englemann. Supposing the depres essed one to be 
M. applanata, the lobes of the stigma are green, not Atal and about two lines 
long. The lobes of M. hemispherica (?) are four lines 
But there is a something almost indescribable by aa the student of cacti 
an class the “ forms,” and as these are now blooming before me to-day in my 
