11 



47.04 cm. (18.52 in.); the mean annual temperature 

 was 5.4°C (41. 7° F), the mean January minimum was 

 -11.6°C (11.2°F), and the mean July maximum was 

 25.5''C (77.9°F). At Hungry Horse Dam, the mean 

 annual precipitation was 85.09 cm. (33.50 in.); the 

 mean annual temperature was 6.1°C (43.0°F), the mean 

 January minimum was -9.7°C (14.6''F), and the mean 

 July maximum was 26.8°C (80.2''F). 



F. POPULATION DEMOGRAPHY AND BIOLOGY 



1. PHENOLOGY: In Montana, C. passerinum typically 

 begins blooming during the second week of June; peak 

 flowering was observed at the end of the third week 

 in June. Some flowers persist until the first week 

 of July, but the species then goes out of bloom 

 rapidly. Fruiting extends from late June into late 

 July or early August. 



2. POPULATION SIZE AND CONDITION: Because C. 

 passerinum is capable of spreading vegetatively, and 

 can give rise to clusters of stems from the same 

 rootstock, it is difficult to meaningfully estimate 

 the number of distinct individuals in the field. 

 Thus, estimates or exact counts of the number of 

 stems were made for the Montana populations observed 

 in 1988. Populations ranged in size from eight to 

 approximately 1200 stems; these contain from one to 

 four subpopulations. The average number of stems 

 per population observed to date is approximately 

 380; the total number of stems observed in Montana 

 to date is approximately 3000. Two of the four 

 populations in the Bob Marshall Wildernes Area were 

 the largest studied (004, 005), each containing 

 approximately 1200 stems. The smallest sites were 

 in the Front Range, outside the wilderness boundary 

 (002, 006, 007). The smallest of these (Dry Fork 

 Lange Creek (007)) consisted of eight stems in 1988. 



Details regarding population size and condition are 

 summarized in Table 2. 



3. REPRODUCTIVE BIOLOGY 



a. TYPE OF REPRODUCTION: Two methods of 

 reproduction are known to occur commonly in the 

 Orchidaceae: vegetative spread, and sexual 

 production of seeds (Williams and Williams 

 1983) . Cypripedium passerinum is capable of 

 both types of reproduction. 



b. POLLINATION BIOLOGY: Most orchid species rely 

 on insects, especially members of the 

 Hymenoptera and Lepidoptera, for pollination 



