Sept. 1906 ] A New Plowrightia from Guatemala 
187 
stance somewhat brittle but not carbonaceous. The upper portion 
of the pseudoparenchyma is conidiiferous, producing - an abun¬ 
dance of oblong to subglobular reddish or hyaline cells, 7-10x3-5 \x. 
The perithecial cavities are numerous (sometimes 40 or more 
in a stroma), 110-125x90-120 /*; asci numerous, oblong or sub- 
ovate-oblong, the basal part narrowed, 60-90x12-20 fx (mostly 
80-85x14-16 /a), thick-walled, containing 8 subdistichous, sub¬ 
equal, 2-celled, oval-oblong, yellowish or hyaline spores, 20- 
26x5-7 fx (mostly 22-24x5-6 /x). No paraphyses were seen. 
On living and languishing leaves of Agave americana, near 
Guatemala city, C. A., alt. 1200-1800 m. (Circ. 4,000-6,000 ft.) 
W. A. Kellerman Nos. 4629, 4630, 4631, January and February 
1905. 
Plowrightia williamsoniana Kellerm. n. sp.—Stromatibus epi- 
dermidem rumpentibus, prominentibus, globosis, vel sub-quadrangularis vel 
oblongis, *4 ~Va nun. altis, }4-2 mm. longis, in 5-10 (vel pluribus) lineis 
sub-irregulariter concentrice dispositis, intimis majoribus, extimis haud 
multum evolutis, epidermidem vix levantibus, primum maculam definitam 
sub-orbicularem vel oblongam efformantibus, dein cum adjacentibus areis 
affectis confluentibus, saepe folio partim vel omnino tandem infecto. 
Stromatibus primum fulvis, dein fuscis, denique nigris, superficie minute 
papillata, substancia subfragili non carbonacea, parte superiore paren- 
chymatis conidiifera, cellulas numerosas oblongas vel sub-globulares ru- 
bentes vel hyalinas abscindente, 7-10 x 3-5 fx. Loculis perithecialibus nu- 
merosis (plerumque 40 vel pluribus uno in stromate), 110-125x90-120^; 
ascis numerosis, oblongis vel subovato-oblongis, parte inferiore attenu- 
ata, 60-90 x 12-20(saepissime 80-85 x 14-16 /a), parietibus crassis, octo- 
sporis, sporis subdistichis, sub-aequaliter bilocularibus, ovali-oblongis, sub- 
fulvis vel hyalinis, 20-26 x 5-7 fx (plerumque 22-24 x 5-6 fx). Paraphyses 
non apparent. 
In foliis vivis languidisque Agaves americanae, prope urbem Guate¬ 
malan!, Amer. cen., alt. 1,200-1,800 m., W. A. Kellerman, 4629, 4630, 4631, 
in mensibus Jan. et Feb. MCMV. 
Explanation of Plate 90. — Plowrightia williamsoniana Kel¬ 
lerm. Fig. 1. An affected area of a leaf of Agave americana, showing 
the concentric arrangement of the stromata; fig. 2, diagram of a single 
stroma in vertical section; fig. 3, section of a portion of a stroma, show¬ 
ing two perithecial cavities and exhibiting the superficial conidiiferous 
layer; fig. 4, asci; fig. 5, spores; fig. 6, Plowrightia circumscissa Tr. 
& Earle on some Aloe; fig. 7, Colletotrichum agaves Cav. on Agave 
americana. 
