sparsely tomentose to glabrous, often glauco-ceraceous, flower pedicel (3) 4 - 6 (7.5) mm long, 
glabrous; flowers 2.3 - 2.8 mm long, urceolate, white or greenish yellow, tepals 1.6 - 2.3 mm 
long, and 1.3 - 2.1 mm wide, ovate to widely ovate, glabrous outside, sericeous inside, stamens 
of whorls I & II 1 - 2 mm long, their filaments glabrous or sparsely short sericeous ad and 
abaxially, anthers glabrous, stamens of whorl III 1.1 - 1.8 mm long, their filaments sparsely short 
sericeous on the margins and abaxially, anthers glabrous, sporangia four in all stamens, glands 
0.3 - 0.6 mm long, rounded or elliptic, staminodes 0.7 - 1.2 mm long, their filaments glabrous 
adaxially, sparsely pubescent abaxially, apex sparsely pubescent on the base abaxially, glabrous 
elsewhere, hypanthium 0.3 - 0.5 mm deep, glabrous outside and inside, ovary and style glabrous; 
fruit 9 - 13.5 mm long, and 7.5 - 10 mm wide, ellipsoid, seated on the whole persistent tepals, 
pedicel turbinate, reddish. 
This species occurs frequently in oak, and mixed deciduous forest of the inland hills and 
Gulf facing slopes of the eastern Sierra Madre in Mexico, between (200) 600 - 1300 (1600) m of 
altitude. Although it is found also in pine forest of the same area, it is rather rare in this type of 
vegetation. Flowers are present from March to June, but occasionally also in September. Fruits 
ripe from June to August. 
Of the other two species with secondary domatia (C. bractefoliaceum, C. breedlovei) in 
the eastern Sierra Madre C. effusum is easily differentiated by the absence of indument on lower 
leaf surface or, if present, by having only straight appressed hairs. For other distinguishing 
features see comments in those species. 
Lectotypification of the material belonging to this species is still not possible, as Linden 
78 
